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Cisco Systems IOS XR User's Manual

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1. Cisco IOS XR Routing Configuration Guide RC 52 _ mplementing BGP on Cisco 10S XR Software Step 4 Step 5 Command or Action Purpose How to Implement BGP on Cisco IOS XR Software W table policy policy name Example RP 0 RPO CPU0 router config bgp af table policy tbl plcy A Applies the tbl plcy A policy to IPv4 unicast routes being installed into the routing table end or commit Example RP 0 RPO CPU0 router config bgp af end or RP 0 RPO CPU0 router config bgp af commit Saves configuration changes When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Setting BGP Administrative Distance Perform this task to specify the use of administrative distances that can be used to prefer one class of route over another SUMMARY STE
2. Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Step 7 Step 8 Command or Action Purpose end or commit Example RP 0 RPO CPU0 router config isis af end or RP 0 RPO CPU0 router config isis af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session show isis instance instance id spf log level 112 ipv4 ipv6 unicast ispf fsp pre detail internal last number first number Example RP 0 RPO CPU0 router show isis instance 1 spf log ipv4 Optional Displays how often and why the router has run a full SPF calculation Enabling Multicast Intact for IS IS This optional task describ
3. Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software Restrictions MPLS traffic engineering currently supports only a single OSPF area SUMMARY STEPS 1 configure router ospf process name mpls traffic eng area area id area area id interface type instance o Ny oOo fF FSF YS BS end or commit router id ipv4 address interface type interface instance mpls traffic eng router id ip address interface type interface instance 9 show ospf process name area id mpls traffic eng link fragment DETAILED STEPS Command or Action Purpose Step1 configure Example RP 0 RPO CPU0 router configure Enters global configuration mode Step 2 router ospf process name Example RP 0 RPO CPU0 router config router ospf 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode Note The process name argument is any alphanumeric string no longer than 40 characters Step 3 router id ipv4 address interface type interface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IPv4 address as the router ID Step 4 mpls traffic eng area area id Example RP 0 RPO CPU0 router config ospf mpls traffic eng area 0 Configures the OS
4. Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco IOS XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Configuring Aggregate Addresses SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 4 route policy name 5 end or commit DETAILED STEPS Step 1 Step 2 Step 3 How to Implement BGP on Cisco IOS XR Software Hi Perform this task to create aggregate entries in a BGP routing table Command or Action address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast aggregate address address mask length as set as confed set summary only route policy configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process address family ipv4 unicast ipv4 multicast ipv6 unicast ipv multicast Example RP 0 RPO CPU0 router config bgp address family ipv4 unicast Ent
5. Step2 router ospfv3 lt process name gt Enters router configuration mode for OSPFv3 The process name is a WORD that uniquely identifies an OSPF routing process The process name is any alphanumeric string no E le cal a longer than 40 characters without spaces RP 0 RPO CPU0 single10 hfr config router ospfv3 test Step3 graceful restart interval lt seconds gt Specifies the interval minimal time between graceful restarts on the current router Example RP 0 RPO CPU0 singlel10 hfr config ospfv3 grace ful restart interval 120 Configuring the Helper Level of the Router This section describes the task of disabling the helper mode on the current router By default a router that is capable of doing an OSPFV3 graceful restart is also enabled to be a helper to a node in graceful mode The graceful restart helper command lets you disable the current router s helper capability SUMMARY STEPS 1 configuration 2 router ospfv3 3 graceful restart helper disable Cisco 10S XR Routing Configuration Guide RC 184 l _Implementing OSPF on Cisco 10S XR Software How to Implement OSPF on Cisco 10S XR Software W DETAILED STEPS Command or Action Purpose Step1 config Enters global configuration mode Example RP 0 RPO CPU0 singlel10 hfr config RP 0 RPO CPU0 single10 hfr config Step2 router ospfv3 lt process name gt Enters router configuration mode for OSPFv3 The process name is a WORD that
6. Note You must enter the commands in the following task list on every IS IS router in the traffic engineered portion of your network Cisco 10S XR Routing Configuration Guide RC 110 _ Implementing IS IS on Cisco 10S XR Software Restrictions How to Implement IS IS on Cisco IOS XR Software Hl MPLS traffic engineering currently supports only a single IS IS level and does not support routing and signaling of LSPs over unnumbered IP links Therefore do not configure the feature over those links SUMMARY STEPS 1 configure router isis instance id mpls traffic eng level 1 2 metric style wide level 1 2 N os oO FP YS DS end or commit address family ipv4 ipv6 unicast mpls traffic eng router id ip address interface name 8 show isis instance instance id mpls traffic eng tunnel 9 show isis instance instance id mpls traffic eng adjacency log 10 show isis instance instance id mpls traffic eng advertisements DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enables IS IS routing for the specified routing instance and places the router in router configuration mode e You can change the level of routing to be performed by a particular routing instance us
7. Default Address Family for show Commands Most of the show commands require the address family afi and subsequent address family safi to be specified as arguments The Cisco IOS XR software parser provides the ability to set the afi and safi so it is not necessary to specify them while executing a show command The parser commands are e set default afi ipv4 ipv6 all e set default safi unicast multicast all The parser automatically sets the default afi value to ipv4 and default safi value to unicast It is necessary to use only the parser commands to change the default afi value from ipv4 or default safi value from unicast Any afi or safi keyword specified in a show command overrides the values set using the parser commands Use the following command to check the currently set value of the afi and safi e show default afi safi How to Implement BGP on Cisco IOS XR Software This section contains instructions for the following tasks e Enabling BGP Routing page RC 28 required e Configuring a Routing Domain Confederation for BGP page RC 31 optional e Resetting eBGP Session Immediately Upon Link Failure page RC 33 optional e Logging Neighbor Changes page RC 34 optional e Adjusting BGP Timers page RC 34 optional e Changing the BGP Default Local Preference Value page RC 35 optional e Configuring the MED Metric for BGP page RC 36 optional e Configuring BGP Weights page RC 38 optional Cisco 10S XR Routi
8. HZ Additional References Cisco IOS XR Routing Configuration Guide LEZ Implementing Static Routes on Cisco IOS XR Software Static routes are user defined routes that cause packets moving between a source and a destination to take a specified path Static routes can be important if the Cisco IOS XR software cannot build a route to a particular destination They are useful for specifying a gateway of last resort to which all unroutable packets are sent This module describes the tasks you need to implement static routes on your Cisco IOS XR network Note Contents For more information about static routes on the Cisco IOS XR software and complete descriptions of the static routes commands listed in this module see the Related Documents section of this module To locate documentation for other commands that might appear while executing a configuration task search online in the Cisco IOS XR software master command index Feature History for Implementing Static Routes on Cisco IOS XR Software Release Modification Release 2 0 This feature was introduced on the Cisco CRS 1 Release 3 0 No modification Release 3 2 Support was added for the Cisco XR 12000 Series Router e Prerequisites for Implementing Static Routes on Cisco IOS XR Software page RC 248 e Information About Implementing Static Routes on Cisco IOS XR Software page RC 248 e How to Implement Static Routes on Cisco IOS XR Software page RC
9. e OSPF MIB To locate and download MIBs for selected platforms using Cisco IOS XR software use the Cisco MIB Locator found at the following URL http cisco com public sw center netmgmt cmtk mibs shtml RFCs RFCs Title RFC 1587 Not so Stubby Area NSSA RFC 1793 OSPF over demand circuit RFC 2328 OSPF Version 2 RFC 2740 OSPFv3 RFC 3623 Graceful OSPF Restart OSPFv2 Cisco 10S XR Routing Configuration Guide Implementing OSPF on Cisco 10S XR Software W Additional References Technical Assistance Description Link The Cisco Technical Support website contains http www cisco com techsupport thousands of pages of searchable technical content including links to products technologies solutions technical tips and tools Registered Cisco com users can log in from this page to access even more content Cisco IOS XR Routing Configuration Guide RC 194 amp Implementing and Monitoring RIB on Cisco IOS XR Software Routing Information Base RIB is a distributed collection of information about routing connectivity among all nodes of a network Each router maintains a RIB containing the routing information for that router RIB stores the best routes from all routing protocols that are running on the system This module describes the tasks you need to perform to implement and monitor RIB on your Cisco IOS XR network Note Contents For more informatio
10. med eq 10 and not destination in 10 1 3 0 24 or community matches any 10 25 35 if fully parenthesized to display the order of evaluation would look like this med eq 10 and not destination in 10 1 3 0 24 or community matches any 10 25 35 The inner not applies only to the destination test the and combines the result of the not expression with the Multi Exit Discriminator MED test and the or combines that result with the community test If the order of operations are rearranged not med eq 10 and destination in 10 1 3 0 24 or community matches any 10 25 35 Cisco 10S XR Routing Configuration Guide Ce Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy then the expression fully parenthesized would look like the following not med eq 10 and destination in 10 1 3 0 24 or community matches any 10 25 35 Multiple Modifications of the Same Attribute When a policy replaces the value of an attribute multiple times the last assignment wins because all actions are executed Because the MED attribute in BGP is one unique value the last value to which it gets set to wins Therefore the following policy results in a route with a MED value of 12 set med 9 set med 10 set med 11 set med 12 This example is trivial but the feature is not It is possible to write a policy that effectively changes the value for an attribute For example
11. Example RP 0 RPO CPU0 router config bgp nbr timers 60 220 Optional Sets the keepalive timer to 60 seconds and the hold time timer to 220 seconds for BGP neighbor 172 168 40 24 end or commit Example RP 0 RPO CPU0 router config bgp nbr end or RP 0 RPO CPU0 router config bgp nbr commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Changing the BGP Default Local Preference Value Perform this task to set the default local preference value for BGP paths SUMMARY STEPS 1 configure bgp default local preference value PF w N end or commit router bgp autonomous system number Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BG
12. RP 0 RPO CPU0 router config isis end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP 0 RPO CPU0 router config isis commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Step6 show isis instance instance id protocol Optional Displays summary information about the IS IS instance Example RP 0 RPO CPU0 router show isis protocol Configuring Single Topology for IS IS After an IS IS instance is enabled it must be configured to compute routes for a specific network topology This task explains how to configure the operation of the IS IS protocol on an interface for an IPv4 or IPv6 topology Restrictions To enable the router to run in single topology mode configure each of the IS IS interfaces with all of the address families enabled and single topology in the address family IPv6 unicast in the IS IS router stanza You can use either the IPv6 address family or both IPv4 and IPv6 address families but your configuration must represent t
13. Step2 router bgp autonomous system number Enters BGP configuration mode allowing you to configure the BGP routing process Example RP 0 RPO CPU0 router config router bgp 120 Step3 bgp bestpath med missing as worst Directs the BGP software to consider a missing MED attribute in a path as having a value of infinity making this Example path the least desirable path RP 0 RPO CPU0 router config bgp bgp bestpath med missing as worst Step4 bgp bestpath med always Configures the BGP speaker in autonomous system 120 to compare MEDs among alternative paths regardless of the autonomous system from which the paths are received Example RP 0 RPO CPU0 router config bgp bgp bestpath med always Step5 bgp bestpath med confed Enables BGP software to compare MED values for paths learned from confederation peers Example RP 0 RPO CPU0 router config bgp bgp bestpath med confed Step6 bgp bestpath as path ignore Configures the BGP software to ignore the autonomous system length when performing best path selection Example RP 0 RPO CPU0 router config bgp bgp bestpath as path ignore Cisco 10S XR Routing Configuration Guide RC 40 _ mplementing BGP on Cisco 10S XR Software How to Implement BGP on Cisco IOS XR Software W Command or Action Purpose Step7 bgp bestpath compare routerid Configure the BGP speaker in autonomous system 120 to compare the router IDs of similar paths Exam
14. conmig you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RP0 CPU0 router config isis af end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP 0 RP0 CPU0 router config isis af commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuration Examples for Implementing IS IS on Cisco IOS XR Software This section provides the following configuration examples e Configuring Single Topology IS IS for IPv6 Example page RC 122 e Configuring Multitopology IS IS for IPv6 Example page RC 123 e Redistributing IS IS Routes Between Multiple Instances Example page RC 123 Configuring Single Topology IS IS for IPv6 Example The following example shows single topology mode being enabled an IS IS instance being created the NET being defined IPv6 being configured along with IPv4 on an interface and IPv4 link topology being used for IPv6 This configuration allows POS interface 0 3 0 0 to form adjacenc
15. neighbor command RC 153 OSPFv2 Open Shortest Path First Version 2 authentication configuring RC 155 Cisco IOS XR OSPFv3 and OSPF v2 differences RC 131 CLI command line interface inheritance RC 131 configuration MPLS TE RC 175 neighbors nonbroadcast networks RC 150 configuration and operation verifying RC 180 description RC 127 Designate Router DR RC 136 enabling RC 145 functional overview RC 129 instance and router ID RC 134 LSA controlling the frequency RC 158 Cisco 10S XR Routing Configuration Guide W index on an OSPF ABR RC 164 types RC 137 MDS authentication RC 135 MPLS TE configuring RC 175 neighbors adjacency RC 136 neighbors nonbroadcast networks configuring RC 150 nonstop forwarding configuring RC 173 description RC 140 policy attach points default originate RC 231 redistribute RC 231 RC 233 route authentication methods key rollover RC 136 MD5 RC 135 plain text RC 135 strategies RC 136 route redistribution configuring RC 166 description RC 139 Shortest Path First SPF throttling configuring RC 170 description RC 139 stub and not so stubby area types configuring RC 147 supported OSPF network types NBMA networks RC 135 point to point networks RC 135 virtual link creating RC 160 transit area RC 138 OSPFv2 Open Shortest Path Fisrt version 2 enabling multicast intact RC 186 OSPFv3 Open Shortest Path First Version 3 RC 170 addresses importing RC 131 Cisco IOS XR OSPFv3 and OS
16. Cisco 10S XR Routing Configuration Guide JL Rc 201 Implementing and Monitoring RIB on Cisco 10S XR Software HE Where to Go Next L 192 168 20 2 32 is directly connected 00 13 27 GigabitEthernet2 0 L 10 254 254 1 32 is directly connected 00 13 26 GigabitEthernet2 2 Output of show route longer prefixes Command Example The following is sample output from the show route longer prefixes command RP 0 RPO CPU0 router show route ipv4 172 16 0 0 8 longer prefixes Codes C connected S static I IGRP R RIP M mobile B BGP O OSPF IA OSPF inter area N1 OSPF NSSA external type 1 N2 OSPF NSSA external type 2 El OSPF external type 1 E2 OSPF external type 2 E EGP i ISIS L1 IS IS level 1 L2 IS IS level 2 ia IS IS inter area su IS IS summary null candidate default U per user static route o ODR L local Gateway of last resort is 172 23 54 1 to network 0 0 0 0 S 172 16 2 0 32 is directly connected 00 00 24 Loopback0 S 172 16 3 0 32 is directly connected 00 00 24 Loopback0 Ss 172 16 4 0 32 is directly connected 00 00 24 Loopback0O S 172 16 5 0 32 is directly connected 00 00 24 Loopback0 sS 172 16 6 0 32 is directly connected 00 00 24 Loopback0 S 172 16 7 0 32 is directly connected 00 00 24 Loopback0 S 172 16 8 0 32 is directly connected 00 00 24 Loopback0 S 172 16 9 0 32 is directly connected 00 00 24 Loopback0 Output of show route next hop
17. Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IPv4 address as the router ID area area id Example RP 0 RPO CPU0 router config ospf area 1 Enters area configuration mode and configures a nonbackbone area for the OSPF process e The area id argument can be entered in dotted decimal or IPv4 address notation such as area 1000 or area 0 0 3 232 However you must choose one form or the other for an area We recommend using the IPv4 address notation virtual link router id Example RP 0 RPO CPU0 router config ospf ar virtual link 10 3 4 5 Defines an OSPF virtual link e See the Virtual Link and Transit Area for OSPF section on page RC 138 authentication message digest Example RP 0 RPO CPU0 router config ospf ar vl1 authentication message digest Selects MD5 authentication for this virtual link Cisco 10S XR Routing Configuration Guide _ mplementing OSPF on Cisco 10S XR Software Step 8 Step 9 Step 10 Step 11 Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose message digest key key id md5 key clear key encrypted key Example RP 0 RPO CPU0 router config ospf ar vl message digest key 4 md5 yourkey Defines an OSPF virtual link e See the Virtual Link and Transit Area for OSPF section on page RC 138 to
18. How to Implement BGP on Cisco IOS XR Software W Clearing Caches Tables and Databases Perform this task to remove all contents of a particular cache table or database Clearing a cache table or database can become necessary when the contents of the particular structure have become or are suspected to be invalid SUMMARY STEPS 1 clear bgp ip address 2 clear bgp external 3 clear bgp DETAILED STEPS Command or Action Purpose Step1 clear bgp ip address Clears neighbor 172 20 1 1 Example RP O0 RPO CPU0 router clear bgp 172 20 1 1 Step2 clear bgp external Clears all external peers Example RP 0 RPO CPU0 router clear bgp external Step3 clear bgp Clears all BGP neighbors Example RP O0 RPO CPU0 router clear bgp Displaying System and Network Statistics Perform this task to display specific statistics such as the contents of BGP routing tables caches and databases Information provided can be used to determine resource usage and solve network problems You can also display information about node reachability and discover the routing path that the packets of your device are taking through the network SUMMARY STEPS 1 show bgp cidr only show bgp count only show bgp community community list exact match show bgp regexp regular expression show bgp eo aea YS NN show bgp neighbors ip address advertised routes dampened routes flap statistics performance statistics received prefix filt
19. In the following example the show bgp route policy command is used to display any BGP routes carrying a MED of 5 route policy sample display if med eq 5 then pass endif end policy I show bgp route policy sample display A show bgp policy route policy command also exists which runs all routes in the RIB past the named policy as if the RIB were an outbound BGP policy This command then displays what each route looked like before it was modified and after it was modified as shown in the following example RP 0 RP0 CPU0 router show rpl route policy test2 route policy test2 if destination in 10 0 0 0 8 ge 8 le 32 then set med 333 endif end policy l RP 0 RP0 CPU0 router show bgp BGP router identifier 10 0 0 1 local AS number 2 BGP main routing table version 11 BGP scan interval 60 secs Status codes s suppressed d damped h history valid gt best i internal S stale Origin codes i IGP e EGP incomplete Network Next Hop Metric LocPrf Weight Path gt 10 0 0 0 020 22 10 03 gt 10 0 0 0 9 t0 Pe a LO 03 gt 10 0 0 0 10 10 0 1 2 LO 03 ee 104 0 0 07 11 10 0 1 2 LO 03 gt 2001 0 0716 10 0 1 2 10 03 gt 10 3 30 0 24 002 10 03 gt 10 3 30 128 25 100 T2 10 03 gt 10 128 0 0 9 L0 0 1 2 10 03 gt 10 255 0 0 24 10 0 101 2 1000 555 0100 e gt 10 255 64 0 24 10 0 101 2 1000 555 0100 e Cisco IOS XR Routing Configuration Guide RC 228 Implementing R
20. You can enable multicast intact in the IGP when multicast routing protocols PIM are configured and IGP shortcuts are configured on the router IGP shortcuts are MPLS tunnels that are exposed to IGP The IGPs routes IP traffic over these tunnels to destinations that are downstream from the egress router of the tunnel from an SPF perspective PIM cannot use IGP shortcuts for propagating PIM joins because reverse path forwarding RPF cannot work across a unidirectional tunnel When you enable multicast intact on an IGP the IGP publishes a parallel or alternate set of equal cost next hops for use by PIM These next hops are called mcast intact next hops The mcast intact next hops have the following attributes They are guaranteed not to contain any IGP shortcuts They are not used for unicast routing but are used only by PIM to look up an IPv4 next hop to a PIM source They are not published to the FIB When multicast intact is enabled on an IGP all IPv4 destinations that were learned through link state advertisements are published with a set equal cost mcast intact next hops to the RIB This attribute applies even when the native next hops have no IGP shortcuts In OSPF the max paths number of equal cost next hops limit is applied separately to the native and mcast intact next hops The number of equal cost mcast intact next hops is the same as that configured for the native next hops In IS IS the behavior is slightly different
21. However the applied policy does set an attribute for some routes and this disposition is passed along to policy one The result is that policy one passes routes with destinations in network 10 and drops all others Policy statements are processed sequentially in the order in which they appear in the configuration Policies that hierarchically reference other policy blocks are processed as if the referenced policy blocks had been directly substituted inline For example if the following policies are defined route policy one set weight 100 end policy route policy two set med 200 end policy route policy three apply two set community 2 666 additive end policy route policy four apply one apply three pass end policy Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy Policy four could be rewritten in an equivalent way as follows route policy four equivalent set weight 100 set med 200 set community 2 666 additive pass end policy Note The pass statement is not required and can be removed to represent the equivalent policy in another way Policy Verification Range Checking Several different types of verification occur when policies are being defined and used As policies are being defined some simple verifications such as range checking of values is done For example the MED that is being
22. RP 0 RPO CPU0 router config isis if commit Saves configuration changes When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session show isis instance instance id adjacency interface type interface instance detail systemid system id Example RP O0 RPO CPU0 router show isis instance isp adjacency ipv4 Optional Displays IS IS adjacencies show isis adjacency log Example RP 0 RPO CPU1 router show isis adjacency log Optional Displays a log of the most recent adjacency state transitions Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Command or Action Purpose Step12 show isis instance instance id interface type Optional Displays information abo
23. RP 0 RPO CPU0 router config ospf ar range 4004 000 32 advertise Consolidates and summarizes OSPF routes at an area boundary e The advertise keyword causes the software to advertise the address range of subnetworks in a Type 3 summary LSA e The not advertise keyword causes the software to suppress the Type 3 summary LSA and the subnetworks in the range remain hidden from other areas e In the first example all subnetworks for network 192 168 0 0 are summarized and advertised by the ABR into areas outside the backbone e Inthe second example two or more IPv4 interfaces are covered by a 192 x x network Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco IOS XR Software HT How to Implement OSPF on Cisco 10S XR Software Step 6 Step 7 Command or Action Purpose interface type instance Example RP 0 RPO CPU0 router config ospf ar interface POS 0 2 0 3 Enters interface configuration mode and associates one or more interfaces to the area end or commit Example RP 0 RPO CPU0 router config ospf ar end or RP 0 RPO CPU0 router config ospf ar commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configu
24. Step1 config Enters global configuration mode Example RP 0 RPO CPU0 singlel10 hfr config RP 0 RPO CPU0 single10 hfr config Step2 router ospfv3 lt process name gt Enters router configuration mode for OSPFv3 The process name is a WORD that uniquely identifies an OSPF routing process The process name is any alphanumeric string no E le cesta ia longer than 40 characters without spaces RP 0 RPO CPU0 singlel10 hfr config router ospfv3 test Step3 graceful restart lifetime Specifies a maximum duration for a graceful restart Example RP 0 RPO CPU0 singlel0 hfr config ospfv3 grace ful restart lifetime 120 Configuring the Minimum Time Required Between Restarts This section describes the task of modifying the minimal time that is required between allowable graceful restarts The purpose of this interval is to prevent the waste of system resources if the OSPFv3 process is repeatedly crashing for reasons that must be diagnosed The default value for the interval is 90 seconds The range is 90 3600 seconds SUMMARY STEPS 1 configuration 2 router ospfv3 3 graceful restart interval Cisco 10S XR Routing Configuration Guide Ta Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software DETAILED STEPS Command or Action Purpose Step1 config Enters global configuration mode Example RP 0 RPO CPU0 singlel10 hfr config RP 0 RPO CPU0 single10 hfr config
25. Step3 bgp confederation identifier Specifies a BGP confederation identifier of 5 autonomous system number Example RP 0 RPO CPU0 router config bgp bgp confederation identifier 5 Cisco 10S XR Routing Configuration Guide RC 32 _ mplementing BGP on Cisco 10S XR Software Command or Action How to Implement BGP on Cisco IOS XR Software Hil Purpose Step4 bgp confederation peers autonomous system number Example P 0 RPO CPUO onfederation P 0 RPO CPUO onfederation P 0 RPO CPUO onfederation P 0 RPO CPUO onfederation P 0 RPO CPUO onfederation P 0 RPO CPUO confederation Aawawnawwnaawa wD router peers gt router peers gt router peers router peers router peers gt router peers config bgp 1091 config bgp 1092 config bgp 1093 config bgp 1094 config bgp 1095 config bgp 1096 bgp bgp bgp bgp bgp bgp Specifies that the BGP autonomous systems 1091 1092 1093 1094 1095 and 1096 belong to BGP confederation identifier 5 Step5 end or commit Example RP 0 RPO CPUO or RP 0 RPO CPUO router config bgp end router config bgp commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configurati
26. command modes command history defaults usage guidelines and examples IS IS Commands on Cisco IOS XR Software in the Cisco IOS XR Routing Command Reference Release 3 2 OSPF commands complete command syntax command modes command history defaults usage guidelines and examples OSPF Commands on Cisco IOS XR Software in the Cisco IOS XR Routing Command Reference Release 3 2 OSPFv3 commands complete command syntax command modes command history defaults usage guidelines and examples OSPF v3 Commands on Cisco IOS XR Software in the Cisco IOS XR Routing Command Reference Release 3 2 Multicast commands complete command syntax command modes command history defaults usage guidelines and examples Cisco IOS XR Multicast Command Reference Release 3 2 Multicast configuration complete command syntax command modes command history defaults usage guidelines and examples Cisco IOS XR Multicast Configuration Guide Release 3 2 Standards Standards Title No new or modified standards are supported by this feature and support for existing standards has not been modified by this feature MIBs MIBs MIBs Link e IP FORWARD MIB e RFC1213 MIB To locate and download MIBs for selected platforms using Cisco IOS XR software use the Cisco MIB Locator found at the following URL http cisco com public sw center netmgmt cmtk mibs shtml Cisco 10S XR Routing Configur
27. committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Configuring a Route Reflector for BGP Perform this task to configure a route reflector for BGP All the neighbors configured with the route reflector client command are members of the client group and the remaining iBGP peers are members of the nonclient group for the local route reflector Together a route reflector and its clients form a cluster A cluster of clients usually has a single route reflector In such instances the cluster is identified by the software as the router ID of the route reflector To increase redundancy and avoid a single point of failure in the network a cluster can have more than one route reflector If it does all route reflectors in the cluster must be configured with the same 4 byte cluster ID so that a route reflector can recognize updates from route reflectors in the same cluster The bgp cluster id command is used to configure the cluster ID when the cluster has more than one route reflector SUMMARY STEPS 1 configure router bgp autonomous system number bgp cluster id cluster id neighbor ip address remote as autonomous system number address family ipv4 unicast ipv4 mult
28. description RC 195 examples RC 200 functional overview RC 196 IPv4 and IPv6 support RC 197 monitoring RC 198 prerequisites RC 196 route dampening RC 23 route policy BGP command _ RC 31 RC 63 route policy command RC 29 RC 62 route policy pass all command RC 16 route policy submode RC 29 end policy command RC 30 See route policy command router bgp command RC 5 router bgp neighbor group address family configuration mode address family command RC 6 route redistribution OSPFv2 OSPFv3 RC 139 route reflector client command RC 61 route reflectors RC 24 router id command RC 146 router isis address family submode default information originate command RC 121 distance command RC 121 ispf command RC 117 ispf startup delay command RC 117 maximum paths command RC 121 metric style wide command RC 112 Cisco 10S XR Routing Configuration Guide Index mpls traffic eng command RC 111 mpls traffic eng router id command RC 112 redistribute isis command RC 121 set attached bit command RC 122 single topology command RC 96 spf interval command RC 117 summary prefix command RC 121 router isis command RC 100 router isis configuration submode address family command RC 96 ignore lsp errors command RC 104 is type command RC 92 log adjacency changes command RC 114 Isp check interval command RC 103 Isp gen interval command RC 103 Isp mtu command RC 103 Isp password command RC 109 Isp refresh interval command RC 1
29. exit RP 0 RPO CPU0 router config bgp neighbor 192 168 0 1 RP 0 RPO CPU0 router config bgp nbr remote as 1 RP 0 RPO CPU0 router config bgp nbr use session group AS_2 RP 0 RPO CPU0 router config bgp nbr use neighbor group AS_1 The following output from the show bgp neighbors command shows that the advertisement interval used is 15 seconds RP 0 RPO CPU0 router show bgp neighbors 192 168 0 1 BGP neighbor is 192 168 0 1 remote AS 1 local AS 140 external link Remote router ID 0 0 0 0 BGP state Idle Last read 00 00 00 hold time is 180 keepalive interval is 60 seconds Received 0 messages 0 notifications 0 in queue Sent 0 messages 0 notifications 0 in queue Minimum time between advertisement runs is 15 seconds For Address Family IPv4 Unicast BGP neighbor version 0 Update group 0 1 eBGP neighbor with no inbound or outbound policy defaults to drop Route refresh request received 0 sent 0 0 accepted prefixes Prefix advertised 0 suppressed 0 withdrawn 0 maximum limit 524288 Threshold for warning message 75 Connections established 0 dropped 0 Last reset 00 03 23 due to BGP neighbor initialized External BGP neighbor not directly connected 3 Otherwise if the neighbor uses a neighbor group and does not use a session group or address family group the configuration value can be obtained from the neighbor group either directly or through inheritance In the example that follows the advertisement interv
30. if as path originates from 10 then apply param example 10 else pass endif end policy route policy origin 20 if as path originates from 20 then apply param example 20 else pass endif end policy The parameterized policy param example provides a policy definition that is expanded with the values provided as the parameters in the apply statement Note that the policy hierarchy is always maintained Thus if the definition of param example changes then the behavior of origin_10 and origin_20 changes to match The effect of the origin 10 policy is that it adds the community 1234 10 to all routes that pass through this policy and have an AS path indicating the route originated from autonomous system 10 The origin 20 policy is similar except that it adds to community 1234 20 for routes originating from autonomous system 20 Semantics of Policy Application This section discusses how routing policies are evaluated and applied The following concepts are discussed e Boolean Operator Precedence page RC 215 e Multiple Modifications of the Same Attribute page RC 216 e When Attributes Are Modified page RC 216 e Default Drop Disposition page RC 217 e Control Flow page RC 217 e Policy Verification page RC 218 Boolean Operator Precedence Boolean expressions are evaluated in order of operator precedence from left to right The highest precedence operator is not followed by and and then or The following expression
31. multicast all flap statistics regexp regular expression 8 show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics route policy route policy name 9 show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics ip address mask prefix length 10 show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics ip address mask prefix length longer prefixes 11 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics 12 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics regexp regular expression 13 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics route policy route policy name 14 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics network mask length 15 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics ip address 16 show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all dampened paths 17 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicas
32. page RC 79 Enabling BGP Example The following shows how to enable BGP prefix set static 2020 64 2012 64 10 10 0 0 16 10 2 0 0 24 end set route policy pass all pass end policy route policy set_next_hop_agg_v4 set next hop 10 0 0 1 end policy route policy set_next_hop_static_v4 if destination in static then set next hop 10 1 0 1 else drop endif end policy route policy set_next_hop_agg_v6 set next hop 2003 121 end policy route policy set_next_hop_static_v6 if destination in static then set next hop 2011 121 else drop endif end policy router bgp 65000 bgp fast external fallover disable bgp confederation peers 65001 65002 bgp confederation identifier 1 bgp router id 1 1 1 1 address family ipv4 unicast aggregate address 10 2 0 0 24 route policy set_next_hop_agg_v4 aggregate address 10 3 0 0 24 redistribute static route policy set_next_hop_static_v4 Cisco 10S XR Routing Configuration Guide RC 76 _ mplementing BGP on Cisco 10S XR Software Configuration Examples for Implementing BGP on Cisco IOS XR Software W address family ipv4 multicast aggregate address 10 2 0 0 24 route policy set_next_hop_agg_v4 aggregate address 10 3 0 0 24 redistribute static route policy set_next_hop_static_v4 address family ipv6 unicast aggregate address 2012 64 route policy set_next_hop_agg_v6 aggregate address 2013 64 redistribute static route policy set_next_hop_static_v6 address family
33. topology to be seen as entirely different between two neighbors resulting in black holing or routing loops Cisco IOS XR Routing Configuration Guide _ mplementing OSPF on Cisco 10S XR Software Step 14 Step 15 Command or Action Purpose How to Implement OSPF on Cisco 10S XR Software W Repeat Step 13 for all neighbors on the interface end or commit Example RP 0 RPO CPU0 router config ospf ar end or RP 0 RPO CPU0 router config ospf ar commit Saves configuration changes When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuring Authentication at Different Hierarchical Levels for OSPF Version 2 This task explains how to configure MD5 secure authentication on the OSPF router process configure one area with plain text aut
34. 0 RP0 CPU0 router show isis interface POS 0 1 0 1 brief Optional Displays information about the IS IS interface Optional Displays a list of connected routers in all areas show isis instance instance id topology systemid system id level 1 2 ipv4 ipv6 summary unicast Example RP 0 RP0 CPU0 router show isis topology show isis instance instance id adjacency level 1 2 interface type interface instance detail systemid system id Example RP 0 RP0 CPU0 router show isis adjacency Optional Displays state information about established adjacencies show isis adjacency log level 1 2 Example RP 0 RP0 CPU0 router show isis adjacency log level 1 Optional Displays the history of recent adjacency state transitions Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Controlling LSP Flooding for IS IS Flooding of LSPs can limit network scalability You can control LSP flooding by tuning your LSP database parameters on the router globally or on the interface This task is optional Many of the commands to control LSP flooding contain an option to specify the level to which they apply Without the option the command applies to both levels If an option is configured for one level the other level continues to use the default value To configure options for both levels use
35. 0 RPO CPU0 router config bgp nbr af end or RP 0 RPO CPU0 router config bgp nbr af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuring BGP Community and Extended Community Filtering Perform this task to specify that community attributes should be sent to an eBGP neighbor Perform this task to specify that community extended community attributes should be sent to an eBGP neighbor These attributes are not sent to an eBGP neighbor by default By contrast they are always sent to iBGP neighbors This section provides examples on how to enable sending community attributes The send community ebgp keyword can be replaced by the send extended community ebgp keyword to enable sending extended communities Note Ifthe send comm
36. 121 retransmit interval command RC 104 retransmit throttle interval command RC 104 RFC 1142 OSI IS IS Intra domain Routing Protocol RC 125 RFC 1195 Use of OSI IS IS for Routing in TCP IP and Dual Environments RC 125 RFC 1587 Not So Stubby Area NSSA RC 193 RFC 1793 OSPF over demand circuit RC 193 RFC 1997 BGP Communities Attribute RC 80 RFC 2328 OSPF Version 2 RC 130 RC 193 RFC 2385 Protection of BGP Sessions via the TCP MD5 Signature Option RC 80 RFC 2439 BGP Route Flap Damping RC 80 RFC 2545 Use of BGP 4 Multiprotocol Extensions for IPv6 Inter Domain Routing RC 80 RFC 2740 OSPFv3 RC 193 RFC 2740 OSPFv3 RC 130 RFC 2763 Dynamic Hostname Exchange Mechanism for IS IS_ RC 125 RFC 2796 BGP Route Reflection An Alternative to Full Mesh IBGP RC 80 RFC 2858 Multiprotocol Extensions for BGP 4 RC 80 RFC 2918 Route Refresh Capability for BGP 4 RC 80 RFC 2966 Domain wide Prefix Distribution with Two Level IS IS RC 125 RFC 2973 IS IS Mesh Groups RC 125 Index W RFC 3065 Autonomous System Confederations for BGP RC 81 RFC 3277 IS IS Transient Blackhole Avoidance RC 125 RFC 3373 Three Way Handshake for IS IS Point to Point Adjacencies RC 125 RFC 3392 Capabilities Advertisement with BGP 4 RC 81 RFC 3567 IS IS Cryptopgraphic Authentication RC 125 RFC 3623 OSPFv3 RC 193 RIB Routing Information Base administrative distance RC 197 data structures in BGP and other protocols RC 196 deploying RC 198
37. 2 Step 3 Command or Action Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router ospf process name or router ospfv3 process name Example RP 0 RPO CPU0 router config router ospf 1 or RP 0 RPO CPU0 router config router ospfv3 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode or Enables OSPFv3 routing for the specified routing process and places the router in router ospfv3 configuration mode Note The process name argument is any alphanumeric string no longer than 40 characters router id ipv4 address interface type interface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IPv4 address as the router ID Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HZ How to Implement OSPF on Cisco IOS XR Software Command or Action Purpose Step4 redistribute protocol process id level 1 Redistributes OSPF routes from one routing domain to level 1 2 level 2 metric metric value another routing domain metric type type value match internal external 1 2 nssa external 1 2 tag jor tag value route map map tag policy hey F policy tag Redistributes OSPFv3 routes from one routing domain to anothe
38. 232 However you must choose one form or the other for an area We recommend using the IPv4 address notation Cisco 10S XR Routing Configuration Guide Lees Implementing OSPF on Cisco 10S XR Software HZ How to Implement OSPF on Cisco IOS XR Software Step 5 Step 6 Step 7 Step 8 Command or Action Purpose network broadcast non broadcast point to multipoint non broadcast point to point Example RP 0 RPO CPU0 router config ospf ar network non broadcast Configures the OSPF network type to a type other than the default for a given medium e The example sets the network type to NBMA dead interval seconds Example RP 0 RPO CPU0 router config ospf ar dead interval 40 Optional Sets the time to wait for a hello packet from a neighbor before declaring the neighbor down hello interval seconds Example RP 0 RPO CPU0 router config ospf ar hello interval 10 Optional Specifies the interval between hello packets that OSPF sends on the interface interface type instance Example RP 0 RPO CPU0 router config ospf ar interface POS 0 2 0 0 Enters interface configuration mode and associates one or more interfaces for the area configured in Step 4 e In this example the interface inherits the nonbroadcast network type and the hello and dead intervals from the areas because the values are not set at the interface level Cisco 10S XR
39. 3000 0 16 which is itself a recursive route that is it only specifies a next hop The next hop of the BGP route 2001 0DB8 0104 resolves through the static route Therefore the static route would be used to resolve its own next hop It is not normally useful to manually configure a self recursive static route although it is not prohibited However a recursive static route that has been inserted in the routing table may become self recursive as a result of some transient change in the network learned through a dynamic routing protocol If this occurs the fact that the static route has become self recursive will be detected and it will be removed from the routing table although not from the configuration A subsequent network change may cause the static route to no longer be self recursive in which case it will be re inserted in the routing table Cisco 10S XR Routing Configuration Guide Implementing Static Routes on Cisco 10S XR Software HI How to Implement Static Routes on Cisco 10S XR Software Fully Specified Static Routes In a fully specified static route both the output interface and next hop are specified This form of static route is used when the output interface is a multiaccess one and it is necessary to explicitly identify the next hop The next hop must be directly attached to the specified output interface The following example shows a definition of a fully specified static route RP 0 RPO CPU0 router co
40. 8 then drop endif end policy MicroEMACS 3 8b rpl_edit 139281 Parsing 83 bytes parsed in 1 sec 82 bytes sec Committing 1 items committed in 1 sec 0 items sec Updating Updated Commit database in 1 sec RP 0 RPO CPU0 router If there are parse errors you are asked whether editing should continue RP 0 RPO CPU0 router edit route policy policy_B MicroEMACS 3 8b rpl_edit 141738 route policy policy_B set metric type type_1 if destination in 2001 8 then drop endif end policy I MicroEMACS 3 8b rpl_edit 141738 Parsing 105 bytes parsed in 1 sec 103 bytes sec Syntax Authorization errors in one or more commands CONFIGURATION FAILED DUE TO SYNTAX AUTHORIZATION ERRORS set metric type type_1 if destination in 2001 8 then drop endif end policy Continue editing no If you answer yes the editor continues on the text buffer from where you left off If you answer no the running configuration is not changed and the editing session is ended Editing Routing Policy Configuration Elements Using the CLI The CLI allows you to enter and delete route policy statements You can complete a policy configuration block by entering applicable commands such as end policy or end set Alternatively the CLI interpreter allows you to use the exit command to complete a policy configuration block The abort command is used to discard the current policy configuration and return to gl
41. Cisco IOS XR software as such it does not have any special requirements for installation The following are the requirements for base software installation Router Cisco IOS XR software Base package Information About RIB Configuration To implement the Cisco RIB feature you must understand the following concepts e Overview of RIB page RC 196 e RIB Data Structures in BGP and Other Protocols page RC 196 e RIB Administrative Distance page RC 197 e RIB Support for IPv4 and IPv6 page RC 197 Overview of RIB Each routing protocol selects its own set of best routes and installs those routes and their attributes in RIB RIB stores these routes and selects the best ones from among all routing protocols Those routes are downloaded to the line cards for use in forwarding packets The acronym RIB is used both to refer to RIB processes and the collection of route data contained within RIB Within a protocol routes are selected based on the metrics in use by that protocol A protocol downloads its best routes lowest or tied metric to RIB RIB selects the best overall route by comparing the administrative distance of the associated protocol RIB Data Structures in BGP and Other Protocols RIB uses processes and maintains data structures distinct from other routing applications such as Border Gateway Protocol BGP and other unicast routing protocols or multicast protocols such as Protocol Independent Multicast PIM or Multicast Sou
42. Configuration Guide for information on IPv6 routing and addressing Before you enable OSPFV3 on an interface you must perform the following tasks Complete the OSPF network strategy and planning for your IPv6 network For example you must decide whether multiple areas are required Enable IPv6 on the interface Configuring authentication IP Security is an optional task If you choose to configure authentication you must first decide whether to configure plain text or Message Digest 5 MD5 authentication and whether the authentication applies to an entire area or specific interfaces Information About Implementing OSPF on Cisco IOS XR Software To implement OSPF you need to understand the following concepts OSPF Functional Overview page RC 129 Key Features Supported in the Cisco IOS XR OSPF Implementation page RC 130 Comparison of Cisco IOS XR OSPFv3 and OSPFv2 page RC 131 Importing Addresses into OSPFv3 page RC 131 OSPF Hierarchical CLI and CLI Inheritance page RC 131 OSPF Routing Components page RC 132 OSPF Process and Router ID page RC 134 Supported OSPF Network Types page RC 135 Route Authentication Methods for OSPF Version 2 page RC 135 Neighbors and Adjacency for OSPF page RC 136 Designated Router DR for OSPF page RC 136 Default Route for OSPF page RC 137 Link State Advertisement Types for OSPF Version 2 page RC 137 Link State Advertisement Types for OSPFv3 page RC 137 Virtual Link and Tran
43. Describes the link state and costs of a the router link to the area These LSAs are flooded within an area only The LSA indicates whether the router is an ABR or ASBR and if it is one end of a virtual link Type 1 LSAs are also used to advertise stub networks In OSPFV3 these LSAs have no address information and are network protocol independent In OSPFV3 router interface information may be spread across multiple router LSAs Receivers must concatenate all router LSAs originated by a given router before running the SPF calculation Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HZ Information About Implementing OSPF on Cisco 10S XR Software e Network LSA Type 2 Describes the link state and cost information for all routers attached to a multiaccess network segment This LSA lists all OSPF routers that have interfaces attached to the network segment Only the elected designated router for the network segment can generate and track the network LSA for the segment In OSPFv3 network LSAs have no address information and are network protocol independent e Interarea prefix LSA for ABRs Type 3 Advertises internal networks to routers in other areas interarea routes Type 3 LSAs may represent a single network or set of networks aggregated into one prefix Only ABRs generate Type 3 LSAs In OSPFV3 addresses for these LSAs are expressed as prefix and prefix length instead of address and ma
44. Document Revision History page xi e Obtaining Documentation page xii e Documentation Feedback page xiii e Cisco Product Security Overview page xiii e Obtaining Technical Assistance page xiv e Obtaining Additional Publications and Information page xv Document Revision History The Document Revision History table records technical changes to this document Table 1 shows the document revision number for the change the date of the change and a brief summary of the change Note that not all Cisco documents use a Document Revision History table Table 1 Document Revision History Revision Date Change Summary OL 5554 05 November Added description for the OSPFv3 Graceful Restart feature A005 Added descriptions for the multicast intact option in IS IS and OSPFv2 OL 5554 04 August 31 Implementing IS IS on Cisco IOS XR Software changes ss Updated the IS IS module to include the ability to configure a broadcast medium connecting two networking devices as a point to point link OL 5554 02 October 31 Implementing IS IS on Cisco IOS XR Software changes 2004 Changes to lsp gen interval spf interval and show isis spf log information OL 5554 01 July 30 2004 Initial release of this document Cisco 10S XR Routing Configuration Guide E Preface WE Obtaining Documentation Obtaining Documentation Cisco documentation and additional literature are available on Cisco com Cisco also provides seve
45. Example The following is sample output from the show route command when entered without an address RP O0 RPO CPU0O router show route Codes C connected S static I IGRP R RIP M mobile B BGP O OSPF IA OSPF inter area N1 OSPF NSSA external type 1 N2 OSPF NSSA external type 2 El OSPF external type 1 E2 OSPF external type 2 E EGP i ISIS L1 IS IS level 1 L2 IS IS level 2 ia IS IS inter area su IS IS summary null candidate default U per user static route o ODR L local Gateway of last resort is 172 23 54 1 to network 0 0 0 0 Cc 10 2 210 0 24 is directly connected 1d21h Ethernet0 1 0 0 L 10 2 210 221 32 is directly connected 1d21h Ethernet0 1 1 0 Cc 172 20 16 0 24 is directly connected 1d21h ATM4 0 1 Cisco IOS XR Routing Configuration Guide Implementing and Monitoring RIB on Cisco 10S XR Software Configuration Examples for RIB Monitoring Tl 172 20 16 1 32 is directly connected 1d21h ATM4 0 1 Cc 10 6 100 0 24 is directly connected 1d21h Loopback1 L 10 6 200 21 32 is directly connected 1d21h Loopback0 S 192 168 40 0 24 1 0 via 172 20 16 6 1d21h Output of show route backup Command Example The following is sample output from the show route backup command RP 0 RP0 CPU0 router show route backup Codes C connected S static I IGRP R RIP M mobile B BGP O OSPF IA OSPF inter area N1 OSPF NSSA external type 1 N2 OSPF NSSA e
46. From this site you can perform these tasks e Report security vulnerabilities in Cisco products e Obtain assistance with security incidents that involve Cisco products e Register to receive security information from Cisco A current list of security advisories and notices for Cisco products is available at this URL http www cisco com go psirt If you prefer to see advisories and notices as they are updated in real time you can access a Product Security Incident Response Team Really Simple Syndication PSIRT RSS feed from this URL http www cisco com en US products products_psirt_rss_feed html Reporting Security Problems in Cisco Products Cisco is committed to delivering secure products We test our products internally before we release them and we strive to correct all vulnerabilities quickly If you think that you might have identified a vulnerability in a Cisco product contact PSIRT e Emergencies security alert cisco com An emergency is either a condition in which a system is under active attack or a condition for which a severe and urgent security vulnerability should be reported All other conditions are considered nonemergencies e Nonemergencies psirt cisco com In an emergency you can also reach PSIRT by telephone e 1 877 228 7302 e 1 408 525 6532 Cisco 10S XR Routing Configuration Guide Preface WE Obtaining Technical Assistance p Tip We encourage you to use Pretty Good Privacy P
47. How to Implement OSPF on Cisco IOS XR Software This section contains the following procedures Enabling OSPF page RC 145 required Configuring Stub and Not so Stubby Area Types page RC 147 optional Configuring Neighbors for Nonbroadcast Networks page RC 150 optional Configuring Authentication at Different Hierarchical Levels for OSPF Version 2 page RC 155 optional Controlling the Frequency that the Same LSA Is Originated or Accepted for OSPF page RC 158 optional Creating a Virtual Link with MD5 Authentication to Area 0 for OSPF page RC 160 optional Summarizing Subnetwork LSAs on an OSPF ABR page RC 164 optional Redistributing Routes from One IGP into OSPF page RC 166 optional Configuring OSPF Shortest Path First Throttling page RC 170 optional Configuring Nonstop Forwarding for OSPF Version 2 page RC 173 optional Configuring OSPF Version 2 for MPLS Traffic Engineering page RC 175 optional Cisco 10S XR Routing Configuration Guide RC 144 _ mplementing OSPF on Cisco 10S XR Software How to Implement OSPF on Cisco 10S XR Software W e Verifying OSPF Configuration and Operation page RC 180 optional e Configuring OSPFv3 Graceful Restart page RC 181 optional e Enabling Multicast Intact for OSPFv2 page RC 186 optional Enabling OSPF This task explains how to perform the minimum OSPF configuration on your router that is to enable an OSPF process with a router ID configure a backbone
48. Implementing BGP on Cisco 10S XR Software Update group 0 1 eBGP neighbor with no inbound or outbound policy defaults to drop Route refresh request received 0 sent 0 0 accepted prefixes Prefix advertised 0 suppressed 0 withdrawn 0 maximum limit 524288 Threshold for warning message 75 Connections established 0 dropped 0 Last reset 00 00 14 due to BGP neighbor initialized External BGP neighbor not directly connected 2 Otherwise if the neighbor uses a session group or address family group the configuration value is obtained from the session group or address family group If the address family group or session group has a parent and an item is configured on the parent the parent configuration is used If the item is not configured on the parent but is configured on the parent s parent the configuration of the parent s parent is used and so on In the example that follows the advertisement interval is configured on a neighbor group and a session group and the advertisement interval value being used is from the session group RP 0 RPO CPU0O router config router bgp 140 RP 0 RPO CPU0 router config bgp session group AS_2 RP 0 RPO CPU0 router config bgp sngrp advertisement interval 15 RP 0 RPO CPU0 router config bgp sngrp exit RP 0 RPO CPU0 router config bgp neighbor group AS_1 RP 0 RPO CPU0 router config bgp nbrgrp advertisement interval 20 RP 0 RPO CPU0 router config bgp nbrgrp
49. LSAs The prefix is represented by three fields Prefix Length Prefix Options and Address Prefix In OSPFv3 addresses for these LSAs are expressed as prefix and prefix length instead of address and mask The default route is expressed as a prefix with length 0 Inter area prefix and intra area prefix LSAs carry all IPv6 prefix information that in IPv4 is included in router LSAs and network LSAs The Options field in certain LSAs router LSAs network LSAs interarea router LSAs and link LSAs has been expanded to 24 bits to provide support for OSPF in IPv6 In OSPFV3 the sole function of link state ID in interarea prefix LSAs interarea router LSAs and autonomous system external LSAs is to identify individual pieces of the link state database All addresses or router IDs that are expressed by the link state ID in OSPF Version 2 are carried in the body of the LSA in OSPFv3 Virtual Link and Transit Area for OSPF In OSPF routing information from all areas is first summarized to the backbone area by ABRs The same ABRs in turn propagate such received information to their attached areas Such hierarchical distribution of routing information requires that all areas be connected to the backbone area Area 0 Occasions might exist for which an area must be defined but it cannot be physically connected to Area 0 Examples of such an occasion might be if your company makes a new acquisition that includes an OSPF area or if Area 0 its
50. Reference Guide For detailed information about user groups and task IDs see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide Restrictions for Implementing IS IS on Cisco IOS XR Software When multiple instances of IS IS are being run an interface can be associated with only one instance process Instances may not share an interface Additionally if Multiprotocol Label Switching traffic engineering MPLS TE is being employed then MPLS must be enabled for only one instance The MPLS process is not multi instance aware Information About Implementing IS IS on Cisco 10S XR Software To implement IS IS you need to understand the following concepts e IS IS Functional Overview page RC 85 e Key Features Supported in the Cisco IOS XR IS IS Implementation page RC 85 e IS IS Configuration Grouping page RC 85 e Multitopology Configuration page RC 86 e IPv6 Routing and Configuring IPv6 Addressing page RC 86 e Limit LSP Flooding page RC 86 e Maximum LSP Lifetime and Refresh Interval page RC 87 e Overload Bit Configuration During Multitopology Operation page RC 87 e Single Topology IPv6 Support page RC 87 e Multitopology IPv6 Support page RC 88 e Nonstop Forwarding page RC 88 e Multi Instance IS IS page RC 89 e Multiprotocol Label Switching Traffic Engineering page RC 89 e Overload Bit on Router page RC 89 e Default Routes page RC 90 e Attached Bit on an IS IS Instanc
51. Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Command or Action Purpose exit Example RP 0 RPO CPU0 router config if exit Exits interface configuration mode and returns the router to global configuration mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enables IS IS routing for the specified routing instance and places the router in router configuration mode e By default all IS IS instances are Level 1 and Level 2 You can change the level of routing to be performed by a particular routing instance using the is type command net network entity title Example RP 0 RPO CPU0 router config isis net 47 0004 004d 0001 0001 0c11 1110 00 Configures NETs for the routing instance e Specify a NET for each routing instance if you are configuring multi instance IS IS You can specify a name for a NET and for an address e This example configures a router with area ID 47 0004 004d 0001 and system ID 0001 0c11 1110 00 e To specify more than one area address specify additional NETs Although the area address portion of the NET differs the system ID portion of the NET must match exactly for all of the configured items address family ipv6 unicast Example RP 0 RPO CPU0 router config isis address f
52. Routing Domain Confederation for BGP Perform this task to configure the routing domain confederation for BGP This includes specifying a confederation identifier and autonomous systems that belong to the confederation Configuring a routing domain confederation reduces the internal BGP iBGP mesh by dividing an autonomous system into multiple autonomous systems and grouping them into a single confederation Each autonomous system is fully meshed within itself and has a few connections to another autonomous system in the same confederation The confederation maintains the next hop and local preference information and that allows you to retain a single Interior Gateway Protocol IGP for all autonomous systems To the outside world the confederation looks like a single autonomous system Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 bgp confederation identifier autonomous system number 4 bgp confederation peers autonomous system number 5 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RPO CPU0 router configure Step2 router bgp autonomous system number Enters BGP configuration mode allowing you to configure the BGP routing process Example RP 0 RPO CPU0 router config router bgp 120
53. Specifies the MD5 authentication key for the OSPF process e The neighbor routers must have the same key identifier Cisco IOS XR Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software Step 6 Step 7 Step 8 Step 9 Step 10 Step 11 Step 12 Step 13 Step 14 Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose area area id Example RP 0 RPO CPU0 router config ospf area 0 Enters area configuration mode and configures a backbone area for the OSPF process interface type instance Example RP 0 RPO CPU0 router config ospf ar interface POS 0 1 0 3 Enters interface configuration mode and associates one or more interfaces to the backbone area e All interfaces inherit the authentication parameter values specified for the OSPF process Step 4 Step 5 and Step 6 Repeat Step 7 for each interface that must communicate using the same authentication exit Example RP 0 RPO CPU0 router config ospf ar exit Enters area OSPF configuration mode area area id Example RP 0 RPO CPU0 router config ospf area 1 Enters area configuration mode and configures a nonbackbone area 1 for the OSPF process e The area id argument can be entered in dotted decimal or IPv4 address notation such as area 1000 or area 0 0 3 232 However you must choose one form or the other for an area We recommend using the IPv4 address notati
54. Step 4 Step 5 Command or Action Purpose show route protocol instance afi all ipv4 ipv6 unicast multicast safi all ip address mask Example RP 0 RPO CPU0 router show route list list1 bgp aspo ipv4 unicast 192 168 111 8 Displays the current routes in RIB show route afi all ipv4 ipv unicast multicast safi all backup ip address Example RP 0 RPO CPU0 router show route ipv4 unicast backup 192 168 111 8 Displays backup routes in RIB show route afi all ipv4 ipv6 unicast multicast safi all best local ip address Example RP 0 RPO CPU0 router show route ipv4 unicast best local 192 168 111 8 Displays the best local address to use for return packets from the given destination show route afi all ipv4 ipv unicast multicast safi all connected Example RP O0 RPO CPU0 router show route ipv4 unicast connected Displays the current connected routes of the routing table show route afi all ipv4 ipv6 unicast multicast safi all local interface Example RP 0 RPO CPU0 router show route ipv4 unicast local Displays local routes for receive entries in the routing table Cisco 10S XR Routing Configuration Guide E Implementing and Monitoring RIB on Cisco 10S XR Software W Configuration Examples for RIB Monitoring Command or Action Purpose Step6 show route afi all ipv4 ipv6 unicast multi
55. XR Software HT How to Implement BGP on Cisco 10S XR Software 4 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast 5 soft reconfiguration inbound always 6 end or commit DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Enters neighbor address family configuration mode for the IPv4 address family Cisco 10S XR Routing Configuration Guide RC 68 _ mplementing BGP on Cisco 10S XR Software Command or Action How to Implement BGP on Cisco IOS XR Software W Purpose Step 5 soft reconfiguration inbound always Example RP 0 RPO CPU0 router config bgp nbr af soft reconfiguration inbound always Configures the software to store updates received from neighbor 172 168 40
56. XR Software RC 76 Enabling BGP Example RC 76 Displaying BGP Update Groups Example RC 77 BGP Neighbor Configuration Example RC 78 BGP Confederation Example RC 78 BGP Route Reflector Example RC 79 Where to Go Next RC 79 Additional References RC 80 Cisco IOS XR Routing Configuration Guide Contents W Related Documents RC 80 Standards RC 80 MIBs RC 80 RFCs RC 80 Technical Assistance RC 81 Implementing IS IS on Cisco IOS XR Software RC 83 Contents RC 83 Prerequisites for Implementing IS IS on Cisco IOS XR Software RC 84 Restrictions for Implementing IS IS on Cisco IOS XR Software RC 84 Information About Implementing IS IS on Cisco IOS XR Software RC 84 IS IS Functional Overview RC 85 Key Features Supported in the Cisco IOS XR IS IS Implementation RC 85 IS IS Configuration Grouping RC 85 IS IS Interfaces RC 86 Multitopology Configuration RC 86 IPv6 Routing and Configuring IPv6 Addressing RC 86 Limit LSP Flooding RC 86 Maximum LSP Lifetime and Refresh Interval RC 87 Overload Bit Configuration During Multitopology Operation RC 87 Single Topology IPv6 Support RC 87 Multitopology IPv6 Support RC 88 Nonstop Forwarding RC 88 Multi Instance IS IS RC 89 Multiprotocol Label Switching Traffic Engineering RC 89 Overload Bit on Router RC 89 Default Routes RC 90 Attached Bit on an IS IS Instance RC 90 Multicast Intact Feature RC 90 How to Implement IS IS on Cisco IOS XR Software RC 91 Enabling IS IS a
57. a neighbor is configured to use an address family group the neighbor by default inherits the entire configuration from the address family group However a neighbor does not inherit all of the configuration from the address family group if items are explicitly configured for the neighbor The address family group configuration is entered under the BGP router configuration mode The following example shows how to enter address family group configuration mode RP 0 RPO CPU0 router config router bgp 140 RP 0 RPO CPU0 router config bgp af group afmcast1 address family ipv4 multicast RP 0 RPO CPU0 router config bgp afgrp The session group command allows you to create a session group from which neighbors can inherit address family independent configuration A neighbor inherits the configuration from a session group by way of the use command If a neighbor is configured to use a session group the neighbor by default inherits the entire configuration of the session group A neighbor does not inherit all of the configuration from a session group if a configuration is done directly on that neighbor The following example shows how to enter session group configuration mode RP 0 RPO CPU0 router config router bgp 140 RP 0 RPO CPU0 router config bgp session group session1l RP 0 RPO CPU0 router config bgp sngrp The neighbor group command helps you apply the same configuration to one or more neighbors Neighbor groups can include sessio
58. a summary of the BGP attributes and operators Default Originate The default originate attach point allows the user to conditionally inject the default route 0 0 into the OSPFVv3 link state database which is done by evaluating the attached policy If any routes in the local RIB pass the policy then the default route is inserted into the link state database The following example shows how to generate a default route if any of the routes that match 2001 96 are present in the RIB route policy ospfv3 originate if rib has route in 2001 96 then pass endif end policy Cisco 10S XR Routing Configuration Guide LEZA Implementing Routing Policy on Cisco IOS XR Software Redistribute Information About Implementing Routing Policy Hi router ospfv3 1 default information originate policy ospfv3 originate The redistribute attach point within OSPFVv3 injects routes from other routing protocol sources into the OSPFV3 link state database which is done by selecting the route types it wants to import from each protocol It then sets the OSPFv3 parameters of cost and metric type The policy can control how the routes are injected into OSPFv3 by using the metric type command The following example shows how to redistribute routes from BGP instance instance_15 into OSPF instance 1 using the policy OSPFv3 redist The policy sets the metric type to type 2 for all redistributed routes BGP routes with a tag of 10 have their cost set
59. a tag attribute When a policy is attached to a protocol the protocol checks the policy to ensure the policy operates using route attributes known to the protocol If the protocol uses unknown attributes then the protocol rejects the attachment For example OSPF rejects attachment of a policy that tests the values of BGP communities The situation is made more complex by the fact that each protocol has access to at least two distinct route types In addition to native protocol routes for example BGP or IS IS some protocol policy attach points operate on RIB routes which is the common central representation Using BGP as an example the protocol provides an attach point to apply policy to routes redistributed from the RIB to BGP An attach point dealing with two different kinds of routes permits a mix of operations RIB attribute operations for matching and BGP attribute operations for setting Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy Note The protocol configuration rejects attempts to attach policies that perform unsupported operations The following sections describe the protocol attach points including information on the attributes commands and operations that are valid for each attach point e BGP Policy Attach Points page RC 224 e OSPF Policy Attach Points page RC 231 e OSPFv3 Policy Attach Points
60. accounting counters on the interfaces of interest route policy sample table if as path originates from 10 then set traffic index 10 elseif as path originates from 11 then set traffic index 11 endif end policy router bgp 2 address family ipv4 unicast table policy sample table BGP Attributes and Operators Table 3 summarizes the BGP attributes and operators Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy Table 3 BGP Attributes and Operators Attribute Match Set as path in prepend is local length neighbor is originates from passes though unique length community is empty delete matches any set matches every dampening n a set dampening to set values that control the dampening see Dampening page RC 225 destination in n a extended community is empty delete matches any set matches every local preference n a set med is eq ge le set set set next hop in set origin is set rib has route in n a route type is n a source in n a suppress route n a suppress route tag is eq ge le set traffic index n a set unsuppress route n a unsuppress route weight n a set Some BGP route attributes are inaccessible from some BGP attach points for various reasons For example the set med igp cost only command makes sense when there is a configured i
61. all flap statistics regexp regular expression Example RP O0 RPO CPU0 router clear bgp ipv4 unicast flap statistics _1 Clears BGP flap statistics for all paths that match the regular expression _1 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics route policy route policy nane Example RP 0 RPO CPU0 router clear bgp ipv4 unicast flap statistics route policy policy_A Clears BGP flap statistics for route policy policy_A clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics network mask length Example RP O0 RPO CPU0 router clear bgp ipv4 unicast flap statistics 192 168 40 0 24 Clears BGP flap statistics for network 192 168 40 0 24 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics ip address Example RP O0 RPO CPU0 router clear bgp ipv4 unicast flap statistics 172 20 1 1 Clears BGP flap statistics for routes received from this neighbor 172 20 1 1 show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all dampened paths Example RP 0 RPO CPUO0O router show bgp dampened paths Displays the dampened routes including the time remaining before they are unsuppressed clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast mu
62. and nssa commands without the keywords rather than using the no form of the command e For example the no nssa default information originate form of the command changes the NSSA area into a normal area that inadvertently brings down the existing adjacencies in that area default cost cost Example RP 0 RPO CPU0 router config ospf ar default cost 15 Optional Specifies a cost for the default summary route sent into a stub area or an NSSA e Use this command only on ABRs attached to the NSSA Do not use it on any other routers in the area e The default cost is 1 Cisco 10S XR Routing Configuration Guide Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco 10S XR Software Step 8 Step 9 Command or Action Purpose end or commit Example RP 0 RPO CPU0 router config ospf ar end or RP 0 RPO CPU0 router config ospf ar commit Saves configuration changes When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current conf
63. and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Disabling Next Hop Processing on BGP Updates Perform this task to disable next hop calculation for a neighbor and insert your own address in the next hop field of BGP updates Disabling the calculation of the best next hop to use when advertising a route causes all routes to be advertised with the network device as the next hop amp Note Next hop processing can be disabled for address family group neighbor group or neighbor address family SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 neighbor ip address 4 remote as autonomous system number 5 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast 6 next hop self 7 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP O0 RPO CPU0 router configure Step2 router bgp au
64. and the hold time timer to 220 seconds for the BGP neighbor group nbr grp A ttl security Example RP 0 RPO CPUO ttl security router config bgp nbrgrp Optional Enables TTL security for eBGP neighbor group nbr grp A update source interface type interface number Example RP 0 RPO CPUO update source router config bgp nbrgrp Loopback0O Optional Configures the router to use the IP address from the LoopbackO interface when trying to open a session with neighbor group nbr grp A exit Example RP 0 RPO CPU0 router config bgp nbrgrp exit Exits the current configuration mode neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Command or Action Purpose Step19 use neighbor group group name Optional Specifies that BGP neighbor 172 168 40 24 inherit configuration from neighbor group nbr grp A Example RP 0 RPO CPU0 router config bgp nbr use neighbor group nbr grp A Step 20 end Saves configuration changes or e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example
65. are then sent as updates to the peer or group of peers The routes that are sent may have had their BGP attributes altered by the policy that has been applied The following policy sends all BGP routes to neighbor 10 0 0 5 Routes that are tagged with any community in the range 2 100 to 2 200 are sent with a MED of 100 and a community of 2 666 The rest of the routes are sent with a MED of 200 and a community of 2 200 route policy sample export if community matches any 2 100 200 then set med 100 set community 2 666 else set med 200 set community 2 200 endif end policy router bgp 2 neighbor 10 0 0 5 remote as 3 address family ipv4 unicast route policy sample export out Neighbor Import The neighbor import attach point controls the reception of routes from a specific peer All routes that are received by a peer are run through the attached policy Any routes that pass the attached policy are passed to the BGP Routing Information Base BRIB as possible candidates for selection as best path routes When a BGP import policy is modified it is necessary to rerun all the routes that have been received from that peer against the new policy The modified policy may now discard routes that were previously allowed through allow through previously discarded routes or change the way the routes are modified A new configuration option in BGP bgp auto policy soft reset that allows this modification to happen automatically in cases for whi
66. area command RC 146 redistribute command RC 168 router id command RC 146 summary prefix command RC 169 timers lsa gen interval command RC 159 timers lsa group pacing command RC 160 timers lsa min interval command RC 159 timers throttle spf command RC 171 routes customizing IS IS RC 119 default IS IS_ RC 90 redistribute OSPFv2 OSPFv3 RC 166 redistribute IS IS routes example RC 123 routing components Cisco 10S XR Routing Configuration Guide Area Border Routers ABRs RC 134 Autonomous System Boundary Routers ASBRs RC 134 autonomous systems RC 132 backbone area RC 133 Designated Router DR RC 136 interior routers RC 134 not so stubby area RC 133 stub area RC 133 routing domain confederation RC 24 routing policy RC 16 attaching to BGP neighbor RC 238 configuration elements editing RC 235 defining RC 237 defining example RC 241 enforcing BGP RC 16 implementing prerequisites RC 206 inbound example RC 242 modifying RC 240 modular inbound example RC 243 statements action RC 221 disposition RC 220 elseif RC 221 if RC 221 remark RC 219 RPL routing policy language Boolean operators types RC 222 components RC 211 overview RC 206 policy attributes modification RC 216 parameterization RC 214 Boolean operator precedence RC 215 configuration basics RC 213 default drop disposition RC 217 definitions RC 213 Index statement processing RC 217 statements types RC 219 verification RC
67. autonomous system 30 for the purpose of peering with neighbor group nbr grp A Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Step 10 Step 11 Step 12 Step 13 Step 14 Step 15 Step 16 Step 17 Step 18 Command or Action How to Implement BGP on Cisco IOS XR Software Hil Purpose password clear encrypted password Example RP 0 RPO CPU0 router config bgp nbrgrp password clear pswd123 Optional Configures neighbor group nbr grp A to use MDS authentication with the password pswd123 password disable Example RP 0 RPO CPU0 router config bgp nbrgrp password disable Optional Overrides any inherited password configuration from the neighbor group receive buffer size socket size bgp size Example RP 0 RPO CPU0 router config bgp nbrgrp receive buffer size 45215 5156 Optional Sets the receive buffer sizes for neighbor group nbr grp A to 45215 bytes for the socket buffer and 5156 bytes for the BGP buffer send buffer size socket size bgp size Example RP 0 RPO CPU0 router config bgp nbrgrp send buffer size 8741 8741 Optional Sets the send buffer sizes for neighbor group nbr grp A to 8741 bytes for the socket buffer and 8741 bytes for the BGP buffer timers keepalive hold time Example RP 0 RPO CPUO 60 220 router config bgp nbrgrp timers Optional Sets the keepalive timer to 60 seconds
68. bgp afgrp router config bgp afgrp router config bgp afgrp router config bgp afgrp router config bgp afgrp router config bgp af router config bgp afgrp router c c config bgp afgrp g router config bgp afgrp router config bgp afgrp g onfig bgp af onfig bgp afgrp gp 140 roup GROUP_3 address family ipv4 unicast remove private as route policy POLICY_1 in exit roup GROUP_1 address family ipv4 unicast use af group GROUP_2 maximum prefix 2500 75 warning only default originate exit roup GROUP_2 address family ipv4 unicast use af group GROUP_3 send community ebgp send extended community ebgp capability orf prefix list both Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W The following example displays sample output from the show bgp af group command using the configuration keyword This example shows from where each configuration item was inherited The default originate command was configured directly on this address family group indicated by The remove private as command was inherited from address family group GROUP_2 which in turn inherited from address family group GROUP_3 RP 0 RPO CPU0 router show bgp af group GROUP_1 configuration af group GROUP_1 address family ipv4 unicast capability orf prefix list both defaul
69. cisco com techsupport Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HZ Additional References Cisco 10S XR Routing Configuration Guide RC 126 amp Implementing OSPF on Cisco IOS XR Software Open Shortest Path First OSPF is an Interior Gateway Protocol IGP developed by the OSPF working group of the Internet Engineering Task Force IETF Designed expressly for IP networks OSPF supports IP subnetting and tagging of externally derived routing information OSPF also allows packet authentication and uses IP multicast when sending and receiving packets Implementing OSPF version 3 OSPFv3 expands on OSPF Version 2 to provide support for IPv6 routing prefixes This module describes the concepts and tasks you need to implement both versions of OSPF on your Cisco IOS XR router The term OSPF implies both versions of the routing protocol unless otherwise noted Note Contents For more information about OSPF on the Cisco IOS XR software and complete descriptions of the OSPF commands listed in this module see the Related Documents section of this module To locate documentation for other commands that might appear during execution of a configuration task search online in the Cisco IOS XR software master command index Feature History for Implementing OSPF on Cisco IOS XR Software Release Modification Release 2 0 This feature was introd
70. confederation peers 6001 6002 neighbor 171 69 232 57 remote as 6001 neighbor 171 69 232 55 remote as 6002 neighbor 200 200 200 200 remote as 701 The following is a part of the configuration from the BGP speaker 200 200 200 205 from autonomous system 701 in the same example Neighbor 171 69 232 56 is configured as a normal eBGP speaker from autonomous system 666 The internal division of the autonomous system into multiple autonomous systems is not known to the peers external to the confederation router bgp 701 neighbor 171 69 232 56 remote as 666 neighbor 200 200 200 205 remote as 701 BGP Route Reflector Example The following example shows how to use an address family to configure internal BGP peer 10 1 1 1 as a route reflector client for both unicast and multicast prefixes router bgp 140 neighbor 10 1 1 1 remote as 140 address family ipv4 unicast route reflector client router bgp 140 neighbor 10 1 1 1 remote as 140 address family ipv4 multicast route reflector client Where to Go Next For detailed information about BGP commands see the Cisco IOS XR Routing Command Reference document Cisco 10S XR Routing Configuration Guide RC79 Implementing BGP on Cisco IOS XR Software W Additional References Additional References The following sections provide references related to implementing BGP for Cisco IOS XR software Related Documents Related Topic Document Title BGP commands complete c
71. directly when the router advertises the summary e This example specifies an IPv4 address and mask or e This example specifies an IPv6 prefix and the command must be in the form documented in RFC 2373 in which the address is specified in hexadecimal using 16 bit values between colons e Note that IPv6 prefixes must be configured only in the IPv6 router address family configuration submode and IPv4 prefixes in the IPv4 router address family configuration submode maximum paths route number Example RP 0 RPO CPU0 router config isis af maximum paths 16 Optional Configures the maximum number of parallel paths allowed in a routing table distance weight address prefix length route list name Example RP 0 RPO CPU0 router config isis af distance 90 Optional Defines the administrative distance assigned to routes discovered by the IS IS protocol e A different administrative distance may be applied for IPv4 and IPv6 Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software WE Configuration Examples for Implementing IS IS on Cisco 10S XR Software Command or Action Purpose Step10 set attached bit Optional Configures an IS IS instance with an attached bit in the Level LSP Example RP 0 RPO CPU0 router config isis af set attached bit Step11 end Saves configuration changes or f e When you issue the end command the system prompts
72. e BGP Routing Domain Confederation page RC 24 e BGP Route Reflectors page RC 24 e Default Address Family for show Commands page RC 27 BGP Functional Overview BGP uses TCP as its transport protocol Two BGP routers form a TCP connection between one another peer routers and exchange messages to open and confirm the connection parameters BGP routers exchange network reachability information This information is mainly an indication of the full paths BGP autonomous system numbers that a route should take to reach the destination network This information helps construct a graph that shows which autonomous systems are loop free and where routing policies can be applied to enforce restrictions on routing behavior Any two routers forming a TCP connection to exchange BGP routing information are called peers or neighbors BGP peers initially exchange their full BGP routing tables After this exchange incremental updates are sent as the routing table changes BGP keeps a version number of the BGP table which is the same for all of its BGP peers The version number changes whenever BGP updates the table due to routing information changes Keepalive packets are sent to ensure that the connection is alive between the BGP peers and notification packets are sent in response to error or special conditions Cisco 10S XR Routing Configuration Guide RC 2 _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cis
73. e This command is appropriate only for an NBMA network with highly meshed point to point topologies Cisco IOS XR Routing Configuration Guide _ Implementing IS IS on Cisco 10S XR Software Step 15 Step 16 Step 17 Step 18 Step 19 How to Implement IS IS on Cisco IOS XR Software Hl Command or Action Purpose end or commit Example RP 0 RPO CPU0 router config isis if end or RP 0 RPO CPU0 router config isis if commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session show isis interface type instance level 1 2 brief Example RP 0 RPO CPU0 router show isis interface POSO 1 0 1 brief Optional Displays information about the IS IS interface show isis instance instance id datab
74. else delete community in 123 123 endif pass end policy Set local preference based on community The following example shows how the community set named quickstart communities defines community values The route policy named quickstart localpref tests a route for the presence of the communities specified in the quickstart communities community set If any of the community values are present in the route the route policy sets the local preference attribute of the route to 31 In any case the policy instructs the protocol to accept the route community set quickstart communities 987 654 987 543 987 321 987 210 end set Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy i route policy quickstart localpref if community matches any quickstart communities then set local preference 31 endif pass end policy Persistent Remarks The following example shows how comments are placed in the policy to clarify the meaning of the entries in the set and the statements in the policy The remarks are persistent meaning they remain attached to the policy For example remarks are displayed in the output of the show running config command Adding remarks to the policy makes the policy easier to understand modify at a later date and troubleshoot if an unexpected behavior occurs prefix set rfcl1918 These are the networks defined as private
75. end set route policy in 100 apply common inbound if community matches any 100 120 135 then apply set lpref prepend 100 100 2 set community 2 1234 additive else set local preference 110 endif if community matches any 100 666 100 999 then set med 444 set local preference 200 set community no export additive endif end policy route policy in 101 apply common inbound if community matches any 101 200 201 then apply set lpref prepend 100 101 2 set community 2 1234 additive else set local preference 125 endif end policy I route policy filter bogons if destination in bogon then drop else Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HI Additional References pass endif end policy l route policy common inbound apply filter bogons set origin igp set community 2 333 end policy l route policy set lpref prepend lpref as prependcnt set local preference lpref prepend as path as prependcnt end policy Translating Cisco 10S Route Maps to Cisco IOS XR Routing Policy Language Example RPL performs the same functions as route maps See the Converting Cisco IOS Configurations to Cisco IOS XR Configurations guide Additional References The following sections provide references related to implementing RPL Related Documents Related Topic Document Title Routing policy language commands complete Routing Policy Language
76. gigabitethernet 0 5 0 0 Directly attached static routes are candidates for insertion in the routing table only if they refer to a valid interface that is an interface that is both up and has IPv4 or IPv6 enabled on it Recursive Static Routes In a recursive static route only the next hop is specified The output interface is derived from the next hop The following example shows how to specify that all destinations with address prefix 2001 0DB8 32 are reachable through the host with address 2001 0DB8 3000 1 RP 0 RPO CPU0 router config route ipv6 unicast 2001 0DB8 32 2001 0DB8 3000 1 A recursive static route is valid that is it is a candidate for insertion in the routing table only when the specified next hop resolves either directly or indirectly to a valid output interface provided the route does not self recurse and the recursion depth does not exceed the maximum IPv6 forwarding recursion depth A route self recurses if it is itself used to resolve its own next hop If a static route becomes self recursive RIB sends a notification to static routes to withdraw the recursive route The following example shows how to define a recursive IPv6 static route RP 0 RPO CPU0 router config route ipv6 unicast 2001 0DB8 32 2001 0DB8 3000 1 This static route is not inserted into the IPv6 routing table because it is self recursive The next hop of the static route 2001 0DB8 3000 1 resolves through the BGP route 2001 0DB8
77. in RFC1918 including all subnets thereof 10 0 0 0 8 ge 8 172 16 0 0 12 ge 12 192 168 0 0 16 ge 16 end set route policy quickstart remarks Handle routes to RFC1918 networks if destination in rfc1918 then Set the community such that we do not export the route set community no export additive endif end policy Routing Policy Configuration Basics Route policies comprise series of statements and expressions that are bracketed with the route policy and end policy keywords Rather than a collection of individual commands one for each line the statements within a route policy have context relative to each other Thus instead of each line being an individual command each policy or set is an independent configuration object that can be used entered and manipulated as a unit Each line of a policy configuration is a logical subunit At least one new line must follow the then else and end policy keywords A new line must also follow the closing parenthesis of a parameter list and the name string in a reference to an AS path set community set extended community set or prefix set At least one new line must precede the definition of a route policy AS path set community set extended community set or prefix set One or more new lines can follow an action statement One or more new lines can follow a comma separator in a named AS path set community set extended community set or prefix set A new line must appear at the end of a
78. instances as system resources memory and interfaces allow Each interface may be associated with only a single IS IS instance and MPLS may be enabled for only a single IS IS instance Cisco IOS XR software prevents the double booking of an interface by two instances at configuration time two instances of MPLS configuration causes an error Because the Routing Information Base RIB treats each of the IS IS instances as equal routing clients you must be careful when redistributing routes between IS IS instances The RIB does not know to prefer Level routes over Level 2 routes For this reason if you are running Level 1 and Level 2 instances you must enforce the preference by configuring different administrative distances for the two instances Multiprotocol Label Switching Traffic Engineering The MPLS TE feature enables an MPLS backbone to replicate and expand the traffic engineering capabilities of Layer 2 ATM and Frame Relay networks MPLS is an integration of Layer 2 and Layer 3 technologies For IS IS MPLS TE automatically establishes and maintains MPLS TE label switched paths across the backbone by using Resource Reservation Protocol RSVP The route that a label switched path uses is determined by the label switched paths resource requirements and network resources such as bandwidth Available resources are flooded by using special IS IS TLV extensions in the IS IS The label switched paths are explicit routes and are referred to as
79. interface type interface instance detail systemid system id show isis adjacency log level 1 2 Cisco IOS XR Routing Configuration Guide RC 98 l _ Implementing IS IS on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Command or Action How to Implement IS IS on Cisco IOS XR Software Hi Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode interface type instance Example RP 0 RPO CPU0 router config interface POS 0 1 0 3 Enters interface configuration mode ipv4 address address mask or ipv6 address ipv6 prefix prefix length eui 64 or ipv6 address ipv6 address prefix length link local or ipv6 enable Example RP 0 RPO CPU0O router config if ipv4 address 10 0 lt 143 255 255 255 0 or RP 0 RPO CPU0 router config if ipv6 address 3ffe 1234 c18 1 64 eui 64 or RP 0 RPO CPUO router config if ipv6 address FE80 260 3EFF FE11 6770 link local or RP 0 RPO CPU0 router config if ipv6 enable Defines the IPv4 address for the interface e An IP address is required on all interfaces in an area enabled for IS IS if any one interface is configured for IS IS routing or Specifies an IPv6 network assigned to the interface and enables IPv6 processing on the interface or Specifies an IPv6 address assigned to the interface and enables IPv6 processing on the interfac
80. key command RC 156 metric style wide command RC 112 MPLS TE Multiprotocol Label Switching traffic engineering configuring IS IS RC 110 OSPFv2 RC 175 mpls traffic eng area command RC 176 mpls traffic eng command RC 111 mpls traffic eng router id command RC 112 RC 177 multicast intact IS IS RC 90 OSPFv2 RC 144 multi instance IS IS RC 89 multiprotocol BGP RC 21 multitopology configuring RC 98 example RC 123 NBMA networks RC 135 neighbor address family command RC 5 neighbor command RC 5 neighbor command OSPFv2 OSPFv3 RC 153 neighbor group command RC 56 neighbors adjacency OSPFv2 RC 136 maximum limits BGP RC 3 net command RC 92 RC 251 RC 252 RC 254 network command RC 42 RC 152 next hop self command RC 65 nonstop forwarding configuring OSPFv2 RC 173 not so stubby area RC 133 nsf command RC 106 Index W nsf interface expires command RC 107 nsf interface timer command RC 107 nsf interval command RC 175 nsf lifetime command RC 107 nsg enforce global command RC 174 nssa command RC 149 O ospf area configuration submode dead interval command RC 152 default cost command RC 149 hello interval command RC 152 interface command RC 146 network command RC 152 nssa command RC 149 range command RC 165 stub command RC 149 ospf area submode authentication message digest command RC 162 virtual link command RC 162 ospf interface configuration submode log adjacency changes RC 147
81. logical unit of policy expression and may not appear anywhere else Policy Definitions Policy definitions create named sequences of policy statements A policy definition consists of the CLI route policy keyword followed by a name a sequence of policy statements and the end policy keyword For example the following policy drops any route it encounters Cisco 10S XR Routing Configuration Guide JL Rc 213_ Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy route policy drop everything drop end policy The name serves as a handle for binding the policy to protocols To remove a policy definition issue the no route policy name command Policies may also refer to other policies such that common blocks of policy can be reused This reference to other policies is accomplished by using the apply statement as shown in the following example route policy check as 1234 if as path passes through 1234 then apply drop everything else pass endif end policy The apply statement indicates that the policy drop everything should be executed if the route under consideration passed through autonomous system 1234 before it is received If a route that has autonomous system 1234 in its AS path is received the route is dropped otherwise the route is accepted without modification This policy is an example of a hierarchical policy Thus the semantics of the apply statement are just a
82. mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enables IS IS routing for the specified routing instance and places the router in router configuration mode e You can change the level of routing to be performed by a particular routing instance using the is type router configuration command 1lsp refresh interval seconds level 1 2 Example RP 0 RP0 CPU0 router config isis lsp refresh interval 10800 Optional Sets the time between regeneration of LSPs that contain different sequence numbers e The refresh interval should always be set lower than the max Isp lifetime command 1lsp check interval seconds level 1 2 Example RP 0 RP0 CPU0 router config isis lsp check interval 240 Optional Configures the time between periodic checks of the entire database to validate the checksums of the LSPs in the database e This operation is costly in terms of CPU and so should be configured to occur infrequently 1lsp gen interval initial wait initial secondary wait secondary maximum wait maximum level 11 2 Example RP 0 RPO CPU0 router config isis lsp gen interval maximum wait 15 initial wait 5 Optional Reduces the rate of LSP generation during periods of instability in the network Helps reduce the CPU load on the router and number of LSP transmissions to its IS IS neighbors e During prolonged periods of network instability repeate
83. multiprotocol BGP Autonomous systems 100 200 and 300 are each connected to two NAPs that are FDDI rings One is used for unicast peering and therefore the exchange of unicast traffic The Multicast Friendly Interconnect MFI ring is used for multicast peering and therefore the exchange of multicast traffic Each router is unicast and multicast capable Figure 1 Incongruent Unicast and Multicast Routes FDDI FDDI i o ak 7 1 N we WES KN i git oy i 7 ji ae oe AS 100 AS 200 AS 300 8 N ISP A ISP B ISP C Figure 2 is a topology of unicast only routers and multicast only routers The two routers on the left are unicast only routers that is they do not support or are not configured to perform multicast routing The two routers on the right are multicast only routers Routers A and B support both unicast and multicast routing The unicast only and multicast only routers are connected to a single NAP In Figure 2 only unicast traffic can travel from Router A to the unicast routers to Router B and back Multicast traffic could not flow on that path so another routing table is required Multicast traffic uses the path from Router A to the multicast routers to Router B and back Figure 2 illustrates a multiprotocol BGP environment with a separate unicast route and multicast route from Router A to Router B Multiprotocol BGP allows these routes to be incongruent Both of the autonomous systems must be configured for internal multiprot
84. no advertise is 65535 65282 and local as is 65535 65283 RPL also provides a facility for using wildcards in community specifications A wildcard is specified by inserting an asterisk in place of one of the 16 bit portions of the community specification the wildcard indicates that any value for that portion of the community matches Thus the following policy matches all communities in which the autonomous system part of the community is 123 community set cset3 LS end set Every community set must contain at least one community value Empty community sets are invalid and are rejected An extended community set is analogous to a community set except that it contains extended community values instead of regular community values It also supports named forms and inline forms The following are syntactic examples Named Form extcommunity set extcomm setl RT 1 2 3 4 666 RT 1234 666 S0021 2 3 4 777 SoO 4567 777 end set Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy prefix set Cisco 10S XR Routing Configuration Guide Inline Form RT 1 2 3 4 666 RT 1234 6667 S00 1 2 3 4 777 00745678 777 RT Sipaddr 666 RT 1234 tag So0o0 1 2 3 4 777 SoO tag2 777 As with community sets the inline form supports parameterization within parameterized policies Either portion of the extended community value can b
85. not this step is performed In general the MED is compared if both paths were received from neighbors in the same AS otherwise the MED comparison is skipped However this behavior is modified by certain configuration options and there are also some corner cases to consider See Section 9 1 2 2c of draft ietf idr bgp4 24 txt Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software W Information About Implementing BGP on Cisco 10S XR Software 10 11 12 If the bgp bestpath med always command is configured then the MED comparison is always performed regardless of neighbor AS in the paths Otherwise MED comparison depends on the AS paths of the two paths being compared as follows a Ifa path has no AS path or the AS path starts with an AS_SET then the path is considered to be internal and the MED is compared with other internal paths b If the AS path starts with an AS_SEQUENCE then the neighbor AS is the first AS number in the sequence and the MED is compared with other paths that have the same neighbor AS c If the AS path contains only confederation segments or starts with confederation segments followed by an AS_SET then the MED is not compared with any other path unless the bgp bestpath med confed command is configured In that case the path is considered internal and the MED is compared with other internal paths d Ifthe AS path starts with confederation segments followed by
86. notation such as area 1000 or area 0 0 3 232 However you must choose one form or the other for an area We recommend using the IPv4 address notation Cisco 10S XR Routing Configuration Guide RC 148 _ mplementing OSPF on Cisco 10S XR Software Step 5 Step 6 Step 7 Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose stub no summary or nssa no redistribution default information originate no summary Example RP 0 RPO CPU0 router config ospf ar stub no summary or RP 0 RPO CPU0 router config ospf ar nssa no redistribution Defines the nonbackbone area as a stub area e See the Configuring Stub and Not so Stubby Area Types section on page RC 147 e Specify the no summary keyword to further reduce the number of LSAs sent into a stub area This keyword prevents the ABR from sending summary link state advertisements Type 3 in the stub area or Defines an area as an NSSA e See the Configuring Stub and Not so Stubby Area Types section on page RC 147 stub or nssa Example RP 0 RPO CPU0 router config ospf ar stub or RP 0 RPO CPU0 router config ospf ar nssa Optional Turns off the options configured for stub and NSSA areas e If you configured the stub and NSSA areas using the optional keywords no summary no redistribution default information originate and no summary in Step 5 you must now reissue the stub
87. of seconds to wait for each restart acknowledgment nsf lifetime seconds Example RP 0 RPO CPU0 router config isis nsf lifetime 20 Configures the maximum route lifetime following an NSF restart e This command should be configured to the length of time required to perform a full NSF restart because it is the amount of time that the Routing Information Base RIB retains the routes during the restart e Setting this value too high results in stale routes e Setting this value too low could result in routes purged too soon end or commit Example RP 0 RPO CPU0 router config isis end or RP 0 RPO CPU0 router config isis commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session show running config command
88. on routes learned from internal neighbors to other internal neighbors thus preventing a routing information loop Cisco 10S XR Routing Configuration Guide RC 24 _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W Figure 3 Three Fully Meshed iBGP Speakers Fully meshed autonomous system es Router C Routes es Routes not advertised Ss Routes RouterA advertised External BGP speaker Router A ae Router B With route reflectors all iBGP speakers need not be fully meshed because there is a method to pass learned routes to neighbors In this model an iBGP peer is configured to be a route reflector responsible for passing iBGP learned routes to a set of iBGP neighbors In Figure 4 Router B is configured as a route reflector When the route reflector receives routes advertised from Router A it advertises them to Router C and vice versa This scheme eliminates the need for the iBGP session between routers A and C Figure 4 Simple BGP Model with a Route Reflector Partially meshed autonomous system C Routes Router A External BGP speaker lt A Router C es Reflected routes 4219 SS Router B Route reflector The internal peers of the route reflector are divided into two groups client peers and all other routers in the autonomous system nonclient peers A route reflector reflec
89. only area 1 interfaces on router ABR3 use MD5 authentication router ospf ABR2 router id 10 10 5 5 area 0 area 1 authentication message digest message digest key 100 md5 0 cisco interface pos 0 9 0 1 virtual link 10 10 10 10 area 3 interface Loopback 0 interface pos 0 9 0 0 Where to Go Next To configure route maps through the RPL for OSPF Version 2 see the Implementing Routing Policy on Cisco IOS XR Software document To build an MPLS TE topology create tunnels and configure forwarding over the tunnel for OSPF Version 2 see the Cisco IOS XR MPLS Configuration Guide Cisco 10S XR Routing Configuration Guide RC 192 _ mplementing OSPF on Cisco 10S XR Software Additional References Additional References W The following sections provide references related to implementing OSPF on Cisco IOS XR software Related Documents Related Topic Document Title OSPF and OSPFv3 commands complete command syntax command modes command history defaults usage guidelines and examples Cisco IOS XR Routing Command Reference Release 32 MPLS TE feature information Implementing MPLS Traffic Engineering on Cisco IOS XR Software module in the Cisco IOS XR MPLS Configuration Guide Release 3 2 Standards Standards Title No new or modified standards are supported by this feature and support for existing standards has not been modified by this feature MIBs MIBs MIBs Link
90. period hyphen and underscore A name must begin with a letter or numeral In this context the term set is used in its mathematical sense to mean an unordered collection of unique elements The policy language provides sets as a container for groups of values for matching purposes Sets are used in conditional expressions The elements of the set are separated by commas Null empty sets are not allowed Four kinds of sets exist as path set community set extcommunity set and prefix set You may want to perform comparisons against a small number of elements such as two or three community values for example To allow for these comparisons the user can enumerate these values directly These enumerations are referred to as inline sets Functionally inline sets are equivalent to named sets but allow for simple tests to be inline Thus comparisons do not require that a separate named set be maintained when only one or two elements are being compared See the set types described in the following sections for the syntax In general the syntax for an inline set is a comma separated list Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy as path set Cisco IOS XR Routing Configuration Guide RC 208 surrounded by parentheses as follows lt element entry gt lt element entry gt lt element entry gt lt element entry gt where l
91. policy feature in BGP allows you to configure traffic index values on routes as they are installed in the global routing table This feature is enabled using the table policy command and supports the BGP policy accounting feature BGP policy accounting uses traffic indices that are set on BGP routes to track various counters See Implementing Routing Policy on Cisco IOS XR Software for details on table policy use See the Cisco Express Forwarding Commands on Cisco IOS XR Software module in the Cisco IOS XR IP Addresses and Services Command Reference for details on BGP policy accounting Table policy also provides the ability to drop routes from the RIB based on match criteria This feature can be useful in certain applications and should be used with caution as it can easily create a routing black hole where BGP advertises routes to neighbors that BGP does not install in its global routing table but in the forwarding table Update Groups The BGP Update Groups feature contains an algorithm that dynamically calculates and optimizes update groups of neighbors that share outbound policies and can share the update messages The BGP Update Groups feature separates update group replication from peer group configuration improving convergence time and flexibility of neighbor configuration To use this feature you must understand the following concepts e BGP Update Generation and Update Groups page RC 18 e BGP Update Group page RC 18 BGP Upda
92. policy name in out 12 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RPO CPU0 router configure Step2 route policy name Optional Defines a route policy named drop as 1234 and enters route policy configuration mode Example RP 0 RPO CPUO router config route policy drop as 1234 RP 0 RPO CPU0 router config rpl if as path passes through 1234 then RP 0 RPO CPU0 router config rpl apply check communities RP 0 RPO CPU0 router config rpl else RP 0 RPO CPU0O router config rpl pass RP 0 RPO CPU0 router config rpl endif Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Command or Action Purpose Step 3 end policy Example RP 0 RPO CPU0 router config rpl end policy Optional Ends the definition of a route policy and exits route policy configuration mode Step4 end or commit Example RP 0 RPO CPU0 router config end or RP 0 RPO CPU0 router config commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC
93. process can be thought of as receiving a route from one of the policy clients and then executing the actual policy against the specific route data The fourth component is the policy clients the routing protocols This component calls the execution engine at the appropriate times to have a given policy be applied to a given route and then perform some number of actions These actions may include deleting the route if policy indicated that it should be dropped passing along the route to the protocol decision tree as a candidate for the best route or advertising a policy modified route to a neighbor or peer as appropriate Routing Policy Language Usage This section provides basic routing policy language usage examples See the How to Implement Routing Policy section on page RC 237 for detailed information on how to implement routing policy language The pass policy The following example shows how the policy accepts all presented routes without modifying the routes route policy quickstart pass pass end policy The drop everything policy The following example shows how the policy explicitly rejects all routes presented to it This type of policy is used to ignoring everything coming from a misbehaving peer Cisco 10S XR Routing Configuration Guide my Rc 211 Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy route policy quickstart drop drop end policy Ignore r
94. prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Customizing Routes for IS IS This task describes how to perform route functions that include injecting default routes into your IS IS routing domain and redistributing routes learned at one IS IS level into a different level This task is optional Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software redistribute isis instance level 1 level 2 level 1 2 metric metric metric type internal SUMMARY STEPS 1 configure 2 router isis instance id 3 set overload bit on startup delay wait for bgp level 11 2 4 address family ipv4 ipv6 unicast 5 default information originate route map map name 6 external policy policy name 7 summary prefix addr
95. routes in a limited fashion within the area NSSA allows importing of Type 7 autonomous system external routes within an NSSA area by redistribution These Type 7 LSAs are translated into Type 5 LSAs by NSSA ABRs which are flooded throughout the whole routing domain Summarization and filtering are supported during the translation Use NSSA to simplify administration if you are a network administrator that must connect a central site using OSPF to a remote site that is using a different routing protocol Before NSSA the connection between the corporate site border router and remote router could not be run as an OSPF stub area because routes for the remote site could not be redistributed into a stub area and two routing protocols needed to be maintained A simple protocol like RIP was usually run and handled the redistribution With NSSA you can extend OSPF to cover the remote connection by defining the area between the corporate router and remote router as an NSSA Area 0 cannot be an NSSA Cisco 10S XR Routing Configuration Guide Implementing OSPF on Cisco 10S XR Software HI Information About Implementing OSPF on Cisco 10S XR Software Routers The OSPF network is composed of ABRs ASBRs and interior routers Area Border Routers ABR ABRs are routers with multiple interfaces that connect directly to networks in two or more areas An ABR runs a separate copy of the OSPF algorithm and maintains separate routing data for eac
96. set dampening halflife 30 others default else set dampening halflife 20 others default endif end policy router bgp 2 address family ipv4 unicast bgp dampening policy sample_damp The default originate attach point allows the default route 0 0 0 0 0 to be conditionally generated and advertised to a peer based on the presence of other routes It accomplishes this configuration by evaluating the associated policy against routes in the Routing Information Base RIB If any routes pass the policy the default route is generated and sent to the relevant peer The following policy generates and sends a default route to the BGP neighbor 10 0 0 1 if any routes that match 10 0 0 0 8 ge 8 le 32 are present in the RIB route policy sample originate if rib has route in 10 0 0 0 8 ge 8 le 32 then pass endif end policy router bgp 2 neighbor 10 0 0 1 remote as 3 address family ipv4 unicast default originate policy sample originate Note The current implementation of default origination policy permits matching only on destination address Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software W Information About Implementing Routing Policy Neighbor Export The neighbor export attach point selects the BGP routes to send to a given peer or group of peers The routes are selected by running the set of possible BGP routes through the associated policy Any routes that pass the policy
97. set is checked to verify that it is in a proper range for the MED attribute However this range checking cannot cover parameter specifications because they may not have defined values yet These parameter specifications are verified when a policy is attached to an attach point The policy repository also verifies that there are no recursive definitions of policy and that parameter numbers are correct At attach time all policies must be well formed All sets and policies that they reference must be defined and have valid values Likewise any parameter values must also be in the proper ranges Incomplete Policy and Set References As long as a given policy is not attached at an attach point the policy is allowed to refer to nonexistent sets and policies which allows for freedom of workflow You can build configurations that reference sets or policy blocks that are not yet defined and then can later fill in those undefined policies and sets thereby achieving much greater flexibility in policy definition Every piece of policy you want to reference while defining a policy need not exist in the configuration Thus a user can define a policy sample that references the policy bar using an apply statement even if the policy bar does not exist Similarly a user can enter a policy statement that refers to a nonexistent set However the existence of all referenced policies and sets is enforced when a policy is attached If you attempt to attach the poli
98. static routes that can be configured on a router for a given address family is limited by default to 4000 The limit can be raised or lowered using the route maximum command Note that if you use the route maximum command to reduce the configured maximum allowed number of static routes for a given address family below the number of static routes currently configured the change is rejected In addition understand the following behavior If you commit a batch of routes that would when grouped push the number of static routes configured above the maximum allowed the first n routes in the batch are accepted The number previously configured is accepted and the remainder are rejected The n argument is the difference between the maximum number allowed and number previously configured SUMMARY STEPS 1 configure 2 route maximum ipv4 ipv6 value 3 end or commit Cisco 10S XR Routing Configuration Guide E Implementing Static Routes on Cisco IOS XR Software HZ How to Implement Static Routes on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Command or Action Purpose Enters global configuration mode configure Example RP 0 RPO CPU0 router configure route maximum ipv4 ipv6 value Example RP 0 RPO CPU0 router config route maximum ipv4 10000 Changes the maximum number of allowable static routes e Specify IPv4 or IPv6 address prefixes e Specify the maximum number of static r
99. text preceded by a 0 or encrypted preceded by a 7 form To set the domain password configure the Isp password for Level 2 to set the area password configure the Isp password for Level 1 SUMMARY STEPS 1 configure 2 router isis instance id 3 Isp password hmac md5 text clear encrypted password level 1 2 send only snp send only 4 interface type instance 5 hello password hmac md5 text clear encrypted password level 1 2 send only 6 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RPO CPU0 router configure Step2 router isis instance id Enables IS IS routing for the specified routing instance and places the router in router configuration mode Example e You can change the level of routing to be performed by RP 0 RPO CPUO router config router isis isp a particular routing instance using the is type command Cisco 10S XR Routing Configuration Guide RC 108 l _ Implementing IS IS on Cisco 10S XR Software Step 3 Step 4 Command or Action How to Implement IS IS on Cisco IOS XR Software Hl Purpose lsp password hmac md5 text clear encrypted password level 1 2 send only snp send only Example RP 0 RPO CPU0 router config isis lsp password hmac md5 encrypted passwordl1 level 1 Configures the LSP authentication password Note The hmac md5 keyword specifies that th
100. that it can reach a destination through more than one interface and each path has the same cost it installs each path in the routing table The only restriction on the number of paths to the same destination is controlled by the maximum paths OSPF command The default number of maximum paths is 32 for Cisco CRS 1 routers and 16 for Cisco XR 12000 Series Routers The range is from 1 to 32 for Cisco CRS 1 routers and 1 to 16 for Cisco XR 12000 Series Routers Graceful Restart for OSPFv3 In the current release various restart scenarios in the control plane of an IPv6 enabled router can disrupt data forwarding The OSPFv3 Graceful Restart feature can preserve the data plane capability in the following circumstances e RP failure resulting in a switchover to the backup processor e Planned OSPFV3 process restart such as software upgrade or downgrade e Unplanned OSPFV3 process restart such as a process crash This feature supports non stop data forwarding on established routes while the OSPFV3 routing protocol is restarting Therefore this feature enhances high availability of IPv6 forwarding Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HI Information About Implementing OSPF on Cisco 10S XR Software Modes of Graceful Restart Operation Restart Mode Helper Mode The two operational modes that a router can be in for this feature are restart mode and helper mode Restart mode occurs w
101. the command twice For example RP 0 RPO CPU0 router config isis lsp refresh interval 1200 level 2 RP 0 RPO CPU0 router config isis lsp refresh interval 1100 level 1 SUMMARY STEPS oF W N o o Nn 9 11 12 13 14 15 16 17 18 19 configure router isis instance id lsp refresh interval seconds level 112 Isp check interval seconds level 112 Isp gen interval initial wait initial secondary wait secondary maximum wait maximum level 11 2 Isp mtu bytes level 11 2 max Isp lifetime seconds level 1 2 ignore Isp errors disable interface type instance Isp interval milliseconds level 1 2 csnp interval seconds level 1 2 retransmit interval seconds level 11 2 retransmit throttle interval milliseconds level 1 2 mesh group number blocked end or commit show isis interface type instance level 1 2 brief show isis instance instance id database level 1 2 detail summary verbose sp id show isis instance instance id Isp log level 1 2 show isis database log level 1 2 Cisco 10S XR Routing Configuration Guide _ Implementing IS IS on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Command or Action How to Implement IS IS on Cisco IOS XR Software Hi Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration
102. the path with the higher local preference is chosen Note If a local preference attribute was received with the path or was set by a routing policy then that value is used in this comparison Otherwise the default local preference value of 100 is used The default value can be changed using the bgp default local preference command 4 If one of the paths is a redistributed path which results from a redistribute or network command then it is chosen Otherwise if one of the paths is a locally generated aggregate which results from an aggregate address command it is chosen S Note Steps 1 through 4 implement the Degree of Preference calculation from Section 9 1 1 of draft ietf idr bgp4 24 txt 5 Ifthe paths have unequal AS path lengths the path with the shorter AS path is chosen This step is skipped if bgp bestpath as path ignore command is configured Note when calculating the length of the AS path confederation segments are ignored and AS sets count as 1 See Section 9 1 2 2a of draft ietf idr bgp4 24 txt 6 Ifthe paths have different origins the path with the lower origin is selected Interior Gateway Protocol IGP is considered lower than EGP which is considered lower than INCOMPLETE See Section 9 1 2 2b of draft ietf idr bgp4 24 txt 7 If appropriate the MED of the paths is compared If they are unequal the path with the lower MED is chosen A number of configuration options exist that affect whether or
103. the router e Hello padding applies to only this interface and not to all interfaces hello interval seconds level 1 2 Example RP 0 RP0 CPU0 router config isis if hello interval 6 Specifies the length of time between hello packets that the software sends hello multiplier multiplier level 1 2 Example RP 0 RP0 CPU0 router config isis if hello multiplier 10 Specifies the number of IS IS hello packets a neighbor must miss before the router should declare the adjacency as down e A higher value increases the networks tolerance for dropped packets but also may increase the amount of time required to detect the failure of an adjacent router e Conversely not detecting the failure of an adjacent router can result in greater packet loss E Cisco IOS XR Routing Configuration Guide _ Implementing IS IS on Cisco 10S XR Software Step 8 Step 9 Step 10 Step 11 Command or Action How to Implement IS IS on Cisco IOS XR Software Hl Purpose hello password hmac md5 text clear encrypted password level 1 2 send only Example RP 0 RPO CPU1 router config isis if hello password text clear mypassword Specifies that this system include authentication in the hello packets and requires successful authentication of the hello packet from the neighbor to establish an adjacency end or commit Example RP 0 RPO CPU0 router config isis if end or
104. window of opportunity you can modify a policy in use at an attach point by respecifying it which allows for policies that are in use to be changed without having a window of time in which no policy is applied at the given attach point Note A route policy or set that is in use at an attach point cannot be removed because this removal would result in an undefined reference An attempt to remove a route policy or set that is in use at an attach point results in an error message to the user Nonattached Policy Modification As long as a given policy is not attached at an attach point the policy is allowed to refer to nonexistent sets and policies Configurations can be built that reference sets or policy blocks that are not yet defined and then later those undefined policies and sets can be filled in This method of building configurations gives much greater flexibility in policy definition Every piece of policy you want to reference while defining a policy need not exist in the configuration Thus you can define a policy sample1 that references a policy sample2 using an apply statement even if the policy sample2 does not exist Similarly you can enter a policy statement that refers to a nonexistent set However the existence of all referenced policies and sets is enforced when a policy is attached Thus if a user attempts to attach the policy sample1 with the reference to an undefined policy sample2 at an inbound BGP policy using the s
105. with BGP 4 Technical Assistance Description Link The Cisco Technical Support website contains thousands of pages of searchable technical content including links to products technologies solutions technical tips and tools Registered Cisco com users can log in from this page to access even more content http www cisco com techsupport Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HZ Additional References Cisco 10S XR Routing Configuration Guide RC 82 amp Implementing IS IS on Cisco IOS XR Software Integrated Intermediate System to Intermediate System IS IS Internet Protocol Version 4 IPv4 is a standards based Interior Gateway Protocol IGP Cisco IOS XR implements the IP routing capabilities described in International Organization for Standardization ISO International Engineering Consortium IEC 10589 and RFC 1995 and adds the standard extensions for single topology and multitopology IS IS for IP Version 6 IPv6 This module describes the new and revised tasks you need to implement IS IS IPv4 and IPv6 on your Cisco IOS XR network Note Contents For more information about IS IS on the Cisco IOS XR software and complete descriptions of the IS IS commands listed in this module you can refer to the Related Documents section of this module To locate documentation for other commands that might appear while of executing
106. with the neighbor is terminated immediately after the configuration if the configured maximum number of prefixes is fewer than the number of prefixes that have already been received from the neighbor for the address family BGP Validation of Local Next Hop Addresses When Cisco IOS XR BGP receives a route advertisement from a neighbor it validates the next hop address contained in the route by verifying that the next hop address is not the same as an IP address assigned to an interface on this router for example a local address If the received next hop address is a local address the update is dropped However if the next hop address is set to a local address by the configured inbound policy the update is not dropped is treated as a valid next hop address and is processed normally in Cisco IOS XR BGP This verification means that the router advertises to its neighbors that it has a route to the prefix but any traffic received for that prefix is dropped This blackholing effect is often used to automatically protect against Denial of Service DOS attacks on user hosts An inbound policy is configured that sets the next hop to a local address for example the address of a loopback interface when a route with a particular community is received When a user finds that a host is under a DOS attack a BGP advertisement is sent to the address of the attacked host with the special community attached The advertisement causes the Internet servic
107. 0 Enters BGP configuration mode allowing you to configure the BGP routing process neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer remote as autonomous system number Example RP 0 RPO CPU0 router config bgp nbr remote as 2002 Creates a neighbor and assigns it a remote autonomous system number of 2002 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Enters neighbor address family configuration mode for the IPv4 address family end or commit Example RP 0 RPO CPU0 router config bgp nbr af end or RP 0 RPO CPU0 router config bgp nbr af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or
108. 0000 Number of areas in this router is 1 1 normal 0 stub 0 nssa Graceful Restart enabled last GR 11 12 26 ago took 6 secs Area BACKBONE 0 Number of interfaces in this area is 1 SPF algorithm executed 1 times Number of LSA 6 Checksum Sum 0x0268a7 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 RP 0 0 CPUO LA Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software Displaying Graceful Restart Information for an OSPFv3 Instance The following screen output shows the link state for the instance of OSPFV3 called test RP 0 0 CPU0 LA show ospfv3 test database grace OSPFv3 Router with ID 2 2 2 2 Process ID test Router Link States Area 0 ADV Router Age Seq Fragment ID Link count Bits aes alee 1949 0x8000000e 0 1 None 2222 2007 0x80000011 0 1 None Link Type 8 Link States Area 0 ADV Router Age Seq Link ID Interface Kee heen Boe 180 0x80000006 1 PO0 2 0 0 S202 202 2007 0x80000006 1 POO0 2 0 0 Intra Area Prefix Link States Area 0 ADV Router Age Seq Link ID Ref lstype Ref LSID i Ws Bs bees 180 0x80000006 0 0x2001 0 2323 2 2 2007 0x80000006 0 0x2001 0 Grace Type 11 Link States Area 0 ADV Router Age Seq Link ID Interface 262202 2007 0x80000005 1 PO0 2 0 0 RP 0 0 CPUO LA Enabling Multicast Intact for OSPFv2 This optional task describes how to enable multicas
109. 03 max lsp lifetime command RC 103 net command RC 92 RC 251 RC 252 RC 254 nsf command RC 106 nsf interface expires command RC 107 nsf interface timer command RC 107 nsf lifetime command RC 107 set overload bit command RC 120 router isis interface configuration submode address family command RC 97 circuit type command RC 97 csnp interval command RC 104 hello interval command RC 114 hello multiplier command RC 114 hello padding command RC 114 hello password command RC 110 RC 115 ipv4 address command RC 95 ipv6 address command RC 95 ipv6 enable command RC 95 Isp interval command RC 104 mesh group command RC 104 retransmit interval command RC 104 retransmit throttle interval command RC 104 router isis interface submode mesh group command RC 104 router ospf command RC 146 router ospf configuration submode RC 146 area command RC 146 authentication command RC 156 message digest key command RC 156 mpls traffic eng area command RC 176 mpls traffic eng router id command RC 177 nsf interval command RC 175 redistribute command RC 168 router id command RC 146 summary prefix command RC 169 timers lsa gen interval command RC 159 timers lsa group pacing command RC 160 timers lsa min interval command RC 159 timers throttle spf command RC 171 router ospf configuration submode command nsf command RC 174 router ospf submode nsf enforce global RC 174 router ospfv3 command RC 146 router ospfv3 configuration submode
110. 1 0DB8 32 2001 0DB8 3000 1 201 In this example a floating static IPv6 route is being configured An administrative distance of 201 is configured Default administrative distances are as follows e Connected interface O e Static route 1 Step3 end or commit Example RP 0 RPO CPU0 router config end or RP 0 RPO CPU0 router config commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session E Cisco 10S XR Routing Configuration Guide _ mplementing Static Routes on Cisco 10S XR Software How to Implement Static Routes on Cisco 10S XR Software Ml Changing the Maximum Number of Allowable Static Routes This task explains how to change the maximum number of allowable static routes Restrictions The number of
111. 2 Cisco IOS XR NSF for OSPF Version 2 allows for the forwarding of data packets to continue along known routes while the routing protocol information is being restored following a failover With NSF peer networking devices do not experience routing flaps During failover data traffic is forwarded Cisco 10S XR Routing Configuration Guide RC 140 _Implementing OSPF on Cisco 10S XR Software Information About Implementing OSPF on Cisco 10S XR Software W through intelligent line cards while the standby Route Processor RP assumes control from the failed RP The ability of line cards to remain up through a failover and to be kept current with the Forwarding Information Base FIB on the active RP is key to Cisco IOS XR NSF operation Routing protocols such as OSPF run only on the active RP or DRP and receive routing updates from their neighbor routers When an OSPF NSF capable router performs an RP failover it must perform two tasks to resynchronize its link state database with its OSPF neighbors First it must relearn the available OSPF neighbors on the network without causing a reset of the neighbor relationship Second it must reacquire the contents of the link state database for the network As quickly as possible after an RP failover the NSF capable router sends an OSPF NSF signal to neighboring NSF aware devices This signal is in the form of a link local LSA generated by the failed over router Neighbor networking devices
112. 2 0 1 area 1 range 2300 16 interface POS 0 2 0 0 ABR Stub Area for OSPFv3 Example The following example shows that area is configured as a stub area router ospfv3 1 router id 10 0 0 217 area 0 interface POS 0 2 0 1 area 1 stub interface POS 0 2 0 0 Cisco 10S XR Routing Configuration Guide RC 190 _Implementing OSPF on Cisco 10S XR Software Configuration Examples for Implementing OSPF on Cisco IOS XR Software Hil ABR Totally Stub Area for OSPFv3 Example The following example shows that area is configured as a totally stub area router ospfv3 1 router id 10 0 0 217 area 0 interface POS 0 2 0 1 area 1 stub no summary interface POS 0 2 0 0 Route Redistribution for OSPFv3 Example The following example uses prefix lists to limit the routes redistributed from other protocols Only routes with 9898 1000 in the upper 32 bits and with prefix lengths from 32 to 64 are redistributed from BGP 42 Only routes not matching this pattern are redistributed from BGP 1956 ipv6 prefix list list1 seq 10 permit 9898 1000 32 ge 32 le 64 ipv prefix list list2 seq 10 deny 9898 1000 32 ge 32 le 64 seq 20 permit 0 le 128 router ospfv3 1 router id 10 0 0 217 redistribute bgp 42 redistribute bgp 1956 distribute list prefix list list1l out bgp 42 distribute list prefix list list2 out bgp 1956 area 1 interface POS 0 2 0 0 Virtual Link Configured Through Area 1 for OSPFv3 Example This examp
113. 218 structure as path set inline set form RC 208 as path set named set form RC 208 community set inline set form RC 209 community set named set form RC 209 extended community set inline form RC 210 extended community set named form RC 209 names RC 207 prefix set RC 210 sets RC 207 S send buffer size command RC 57 send community ebgp command RC 67 set attached bit command RC 122 set overload bit command RC 120 show bgp af group command RC 12 RC 13 show bgp cidr only command RC 74 show bgp community command RC 74 show bgp count only command RC 74 show bgp flap statistics command RC 50 show bgp flap statistics reexp command RC 50 show bgp flap statistics route policy command RC 50 show bgp inheritance command RC 12 show bgp neighbor command RC 11 show bgp neighbor group command RC 14 RC 75 show bgp neighbors command RC 74 show bgp paths command RC 75 show bgp reexp command RC 74 show bgp session group command RC 13 show bgp summary command RC 75 show ip route connected command RC 201 show isis adjacency command RC 101 show isis adjacency log command RC 101 show isis command RC 93 Cisco 10S XR Routing Configuration Guide W index show isis database command RC 105 show isis database log command RC 105 show isis interface command RC 116 show isis Isp log command RC 105 show isis mpls command RC 112 show isis mpls traffic eng adjacency log command RC 112 show isis mpls traffic eng advert
114. 23 then pass endif end policy Cisco IOS XR Routing Configuration Guide RC 220 Implementing Routing Policy on Cisco IOS XR Software Action If Information About Implementing Routing Policy Hi Because the effect of an explicit drop statement is immediate routes in 10 0 0 0 16 le 32 are dropped without any further policy processing Other routes are then considered to see if they were advertised by autonomous system 123 If they were advertised they are passed otherwise they are implicitly dropped at the end of all policy processing An action is a sequence of primitive operations that modify a route Most actions but not all are distinguished by the set keyword In a route policy actions can be grouped together For example the following is a route policy comprising three actions route policy actions set med 217 set community 12 34 additive delete community in 12 56 end policy In its simplest form an if statement uses a conditional expression to decide which actions or dispositions should be taken for the given route For example if as path in as path set 1 then drop endif The example indicates that any routes whose AS path is in the set as path set 1 are dropped The contents of the then clause may be an arbitrary sequence of policy statements The following example contains two action statements if origin is igp then set med 42 prepend as path 73 5 endif The CLI provides support for th
115. 24 Soft reconfiguration inbound causes the software to store the original unmodified route in addition to a route that is modified or filtered This allows a soft clear to be performed after the inbound policy is changed Step6 end or commit Example RP 0 RPO CPU0 router config bgp nbr af end or RP 0 RPO CPU0 router config bgp nbr af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Disabling a BGP Neighbor Perform this task to administratively shut down a neighbor without removing the configuration SUMMARY STEPS 1 configure neighbor ip address shutdown oF wN end or commit router bgp autonomous system number Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS X
116. 250 e Configuration Examples page RC 255 e Where to Go Next page RC 255 e Additional References page RC 256 Cisco 10S XR Routing Configuration Guide E Implementing Static Routes on Cisco 10S XR Software HI Prerequisites for Implementing Static Routes on Cisco 10S XR Software Prerequisites for Implementing Static Routes on Cisco IOS XR Software To use this command you must be in a user group associated with a task group that includes the proper task IDs For detailed information about user groups and task IDs see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide Information About Implementing Static Routes on Cisco IOS XR Software To implement static routes you need to understand the following concepts e Static Route Functional Overview page RC 248 e Default Administrative Distance page RC 248 e Directly Connected Routes page RC 249 Static Route Functional Overview Static routes are entirely user configurable and can point to a next hop interface next hop IP address or both In Cisco IOS XR software if an interface was specified then the static route is installed in the Routing Information Base RIB if the interface is reachable If an interface was not specified the route is installed if the next hop address is reachable The only exception to this configuration is when a static route is configured with the permanent attribute in which case i
117. 255 255 255 0 negotiation auto Cisco 10S XR Routing Configuration Guide RC 188 l _Implementing OSPF on Cisco 10S XR Software Configuration Examples for Implementing OSPF on Cisco IOS XR Software Hil router ospf 1 router id 10 2 3 4 area 0 interface POS 0 3 0 0 area 1 interface POS 0 3 0 1 CLI Inheritance and Precedence for OSPF Version 2 Example The following example configures the cost parameter at different hierarchical levels of the OSPF topology and illustrates how the parameter is inherited and how only one setting takes precedence According to the precedence rule the most explicit configuration is used The cost parameter is set to 5 in router configuration mode for the OSPF process Area 1 sets the cost to 15 and area 6 sets the cost to 30 All interfaces in area 0 inherit a cost of 5 from the OSPF process because the cost was not set in area 0 or its interfaces In area 1 every interface has a cost of 15 because the cost is set in area 1 and 15 overrides the value 5 that was set in router configuration mode Area 4 does not set the cost but POS interface 01 0 2 sets the cost to 20 The remaining interfaces in area 4 have a cost of 5 that is inherited from the OSPF process Area 6 sets the cost to 30 which is inherited by POS interfaces 0 1 0 3 and 0 2 0 3 POS interface 0 3 0 3 uses the cost of 1 which is set in interface configuration mode router ospf 1 router id 10 5 4 3 cost 5 area 0
118. 55 are bound to area 0 Interfaces are configured with the interface command while the router is in area configuration mode and the area keyword is not included in the interface statement Cisco 10S XR Software Configuration interface POS 0 3 0 0 ip address 10 1 2 1 255 255 255 255 negotiation auto l router ospf 1 router id 10 2 3 4 area 0 interface POS 0 3 0 0 The following example shows how OSPF interface parameters are configured for an area in Cisco IOS XR software In Cisco IOS XR software OSPF interface specific parameters are configured in interface configuration mode and explicitly defined for area 0 In addition the ip ospf keywords are no longer required Cisco 10S XR Software Configuration interface POS 0 3 0 0 ip address 10 1 2 1 255 255 255 0 negotiation auto router ospf 1 router id 10 2 3 4 area 0 interface POS 0 3 0 0 cost 77 mtu ignore authentication message digest message digest key 1 md5 0 test The following example shows the hierarchical CLI structure of Cisco IOS XR software In Cisco IOS XR software OSPF areas must be explicitly configured and interfaces configured under the area configuration mode are explicitly bound to that area In this example interface 10 1 2 0 24 is bound to area 0 and interface 10 1 3 0 24 is bound to area 1 Cisco 10S XR Software Configuration interface POS 0 3 0 0 ip address 10 1 2 1 255 255 255 0 negotiation auto interface POS 0 3 0 1 ip address 10 1 3 1
119. 68 20 50 Neighbor Address 192 168 4 1 Admin Metric 0 Maximum bandwidth 19440000 Maximum global pool reservable bandwidth 25000000 Maximum sub pool reservable bandwidth Number of Priority 8 Global pool unreserved BW Priority 0 25000000 Priority 2 25000000 Priority 4 25000000 Priority 6 25000000 Sub pool unreserved BW Priority 1 Priority 3 Priority 5 Priority 7 Link instance is 3 Link connected to Point to Point network 23125000 25000000 25000000 25000000 25000000 Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software Priority 0 3125000 Priority 1 3125000 Priority 2 3125000 Priority 3 3125000 Priority 4 3125000 Priority 5 3125000 Priority 6 3125000 Priority 7 3125000 Affinity Bit 0 Sample Output for the show ospf Command After Configuring MPLS TE In the following example the show route ospf EXEC command verifies that the MPLS TE tunnels replaced POS interface 0 3 0 0 and that configuration was performed correctly RP 0 RP0 CPU0 router show route ospf 1 0 O E2 192 168 10 0 24 110 20 via 0 0 0 0 00 00 15 tunnel2 O E2 192 168 11 0 24 110 20 via 0 0 0 0 00 00 15 tunnel2 0 0 0 O E2 192 168 1244 0 24 110 20 via 0 00 00 15 tunnel2 o 192 168 12 0 24 110 2 via 0 0 0 0 00 00 15 tunnel2 Verifying OSPF Configuration and Operation This task explains how to verify the configurati
120. 8 0 1 configuration neighbor 192 168 0 1 remote as 2 advertisement interval 15 ebgp multihop 3 address family ipv4 unicast next hop self route policy POLICY_1 weight 200 address family ipv4 multicast default originate GROU GROU o p B a GROU in ws GROU GROU P_1 s GROUP_2 P_1 P 3 a GROUP_3 P_1 P_1 Use the show bgp af group command to display address family groups Use the configuration keyword to display the effective configuration for the address family group including any settings that have been inherited from address family groups used by this address family group Use the inheritance keyword to display the address family groups from which this address family group is capable of inheriting configuration Use the users keyword to display the neighbors neighbor groups and address family groups that inherit configuration from this address family group The show bgp af group command examples that follow are based on the this sample configuration HAA AA ADA AAA AAAAA P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 HAA NNNUNN PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C vuvuUUvT UT E A T COO Oe 0 router config router b 0 router config bgp af g Oo 0 4 0 0 Oo 2 2 oO router router config bgp afgrp router router config
121. 87 for an example of route redistribution for OSPF OSPF Shortest Path First Throttling OSPF SPF throttling makes it possible to configure SPF scheduling in millisecond intervals and to potentially delay SPF calculations during network instability SPF is scheduled to calculate the Shortest Path Tree SPT when there is a change in topology One SPF run may include multiple topology change events Cisco 10S XR Routing Configuration Guide JL Rc 139 Implementing OSPF on Cisco 10S XR Software Information About Implementing OSPF on Cisco 10S XR Software The interval at which the SPF calculations occur is chosen dynamically and based on the frequency of topology changes in the network The chosen interval is within the boundary of the user specified value ranges If network topology is unstable SPF throttling calculates SPF scheduling intervals to be longer until topology becomes stable SPF calculations occur at the interval set by the timers throttle spf command The wait interval indicates the amount of time to wait until the next SPF calculation occurs Each wait interval after that calculation is twice as long as the previous interval until the interval reaches the maximum wait time specified The SPF timing can be better explained using an example In this example the start interval is set at 5 milliseconds ms initial wait interval at 1000 ms and maximum wait time at 90 000 ms timers spf 5 1000 90000 Figure 8 shows t
122. By default no authentication is enabled referred to as null authentication in RFC 2178 Both plain text and MDS authentication are performed on changed routing information that arrive on an interface The sender and receiver must know the authentication password or key For both types of authentication a router sends a routing update packet with a key and corresponding key number The receiving router checks the key number and key against its own stored key number and key If the key numbers and keys match the router accepts the routing update packet If they do not match the routing update is discarded Plain Text Authentication MD5 Authentication Plain text authentication also known as Type 1 authentication uses a password that travels on the physical medium and is easily visible to someone that does not have access permission and could use the password to infiltrate a network Therefore plain text authentication does not provide security It might protect against a faulty implementation of OSPF or a misconfigured OSPF interface trying to send erroneous OSPF packets MDS authentication provides a means of security No password travels on the physical medium Instead the router uses MD5 to produce a message digest of the OSPF packet plus the key which is sent on the physical medium Using MD5 authentication prevents a router from accepting unauthorized or deliberately malicious routing updates which could compromise your network securit
123. C 224 router identifier router identifier RC 3 routing policy enforcing RC 16 update groups description RC 18 example RC 77 bgp bestpath as path ignore command RC 40 bgp bestpath compare routerid command RC 41 bgp bestpath med always command RC 40 bgp bestpath med confed command RC 40 bgp bestpath med missing as worst command RC 40 bgp confederation identifier command RC 32 bgp confederation peers command RC 33 Cisco 10S XR Routing Configuration Guide W index bgp dampening command RC 49 bgp default local preference command RC 36 bgp global address family submode RC 5 aggregate address command RC 44 bgp dampening command RC 49 distance bgp command RC 54 network command RC 42 redistribute command RC 47 See address family command table policy command RC 53 bgp neighbor address family submode RC 5 next hop self command RC 65 route policy BGP command RC 63 route policy command RC 31 route reflector client command RC 61 See neighbor address family command send community ebgp command RC 67 soft reconfiguration inbound always command RC 69 weight command RC 39 bgp neighbor command RC 5 bgp neighbor group submode RC 6 RC 56 advertisement interval command RC 56 description command RC 56 dmz link bandwidth command RC 56 ebgp multihop command RC 56 local as command RC 56 password accept command RC 57 password disable command RC 57 receive buffer size command RC 57 See neighbor group command See neighbor group comm
124. C 250 required e Configuring a Floating Static Route page RC 251 optional e Changing the Maximum Number of Allowable Static Routes page RC 253 optional Configuring a Static Route This task explains how to configure a static route SUMMARY STEPS 1 configure 2 route ipv4 ipv6 unicast multicast prefix mask ip address interface type interface instance distance tag tag permanent Cisco 10S XR Routing Configuration Guide RC 250 _ mplementing Static Routes on Cisco 10S XR Software 3 end or commit DETAILED STEPS Command or Action How to Implement Static Routes on Cisco 10S XR Software W Purpose Step1 configure Example RP O0 RPO CPU0 router configure Enters global configuration mode Step 2 route ipv4 ipv6 unicast multicast prefix mask ip address interface type interface instance distance tag tag permanent Example RP 0 RPO CPU0 router config route ipv4 unicast 10 0 0 0 8 172 20 16 6 110 Configures an administrative distance of 110 This example shows how to route packets for network 10 0 0 0 through to a router at 172 20 16 6 if dynamic information with administrative distance less than 110 is not available Step3 ena or commit Example RP 0 RPO CPU0 router config end or RP 0 RPO CPU0 router config commit Saves configuration changes When you issue the end command the system prompts you to commit changes Un
125. CPU0 router config rpl end policy Step4 end Saves configuration changes or e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RP0 CPU0 router config end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP 0 RPO CPU0 router config commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Attaching a Routing Policy to a BGP Neighbor This task explains how to attach a routing policy to a BGP neighbor The procedure to attach a routing policy to an IS IS or OSPF neighbor is the same as BGP except that the commands and applicable arguments vary Prerequisites A routing policy must be preconfigured and well defined prior to it being applied at an attach point If a policy is not predefined an error message is generated stating that the policy is not defined SUMMARY STEPS 1 configure router bgp as number neighbor ip address
126. Cisco SYSTEMS Cisco IOS XR Routing Configuration Guide Cisco IOS XR Software Release 3 2 Corporate Headquarters Cisco Systems Inc 170 West Tasman Drive San Jose CA 95134 1706 USA http www cisco com Tel 408 526 4000 800 553 NETS 6387 Fax 408 526 4100 Text Part Number OL 5554 05 WS THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS IN THIS MANUAL ARE SUBJECT TO CHANGE WITHOUT NOTICE ALL STATEMENTS INFORMATION AND RECOMMENDATIONS IN THIS MANUAL ARE BELIEVED TO BE ACCURATE BUT ARE PRESENTED WITHOUT WARRANTY OF ANY KIND EXPRESS OR IMPLIED USERS MUST TAKE FULL RESPONSIBILITY FOR THEIR APPLICATION OF ANY PRODUCTS THE SOFTWARE LICENSE AND LIMITED WARRANTY FOR THE ACCOMPANYING PRODUCT ARE SET FORTH IN THE INFORMATION PACKET THAT SHIPPED WITH THE PRODUCT AND ARE INCORPORATED HEREIN BY THIS REFERENCE IF YOU ARE UNABLE TO LOCATE THE SOFTWARE LICENSE OR LIMITED WARRANTY CONTACT YOUR CISCO REPRESENTATIVE FOR A COPY The Cisco implementation of TCP header compression is an adaptation of a program developed by the University of California Berkeley UCB as part of UCB s public domain version of the UNIX operating system All rights reserved Copyright 1981 Regents of the University of California NOTWITHSTANDING ANY OTHER WARRANTY HEREIN ALL DOCUMENT FILES AND SOFTWARE OF THESE SUPPLIERS ARE PROVIDED AS IS WITH ALL FAULTS CISCO AND THE ABOVE NAMED SUPPLIERS DISCLAIM ALL WARRANTIES EXPRESSED OR IMPLIED INCL
127. Command Example The following is sample output from the show route next hop command RP 0 RPO CPUO router show route next hop 10 0 0 1 Routing entry for 10 0 0 0 24 Known via connected distance 0 metric 0 connected Routing Descriptor Blocks 10 0 0 50 directly connected via GigabitEthernet6 0 Route metric is 0 Where to Go Next For additional information on the protocols that interact with RIB you may want to see the following publications e Implementing BGP on Cisco IOS XR Software e Implementing IS IS on Cisco IOS XR Software e Implementing OSPF on Cisco IOS XR Software e RIB Commands on Cisco IOS XR Software Cisco 10S XR Routing Configuration Guide RC 202 Implementing and Monitoring RIB on Cisco 10S XR Software Additional References Additional References W The following sections provide references related to implementing RIB on Cisco IOS XR software Related Documents Related Topic Document Title Routing Information Base commands complete command syntax command modes command history defaults usage guidelines and examples RIB Commands on Cisco IOS XR Software in the Cisco IOS XR Routing Command Reference Release 3 2 BGP commands complete command syntax command modes command history defaults usage guidelines and examples BGP Commands on Cisco IOS XR Software in the Cisco IOS XR Routing Command Reference Release 3 2 IS IS commands complete command syntax
128. Commands on Cisco IOS XR Software command syntax command modes command history Release 3 2 defaults usage guidelines and examples Regular expression syntax Understanding Regular Expressions Special Characters and Patterns appendix in the Cisco IOS XR Getting Started Guide Standards Standards Title Draft ietf idr bgp4 26 txt A Border Gateway Protocol 4 by Y Rekhter T Li S Hares Cisco IOS XR Routing Configuration Guide RC 244 Implementing Routing Policy on Cisco IOS XR Software MIBs MIBs Additional References W MIBs Link There are no applicable MIBs for this module To locate and download MIBs for selected platforms using Cisco IOS XR software use the Cisco MIB Locator found at the following URL http cisco com public sw center netmgmt cmtk mibs shtml RFCs RFCs Title No new or modified RFCs are supported by this feature and support for existing RFCs has not been modified by this feature Technical Assistance Description Link The Cisco Technical Support website contains thousands of pages of searchable technical content including links to products technologies solutions technical tips and tools Registered Cisco com users can log in from this page to access even more content http www cisco com techsupport Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software
129. Example RP 0 RPO CPU0 router show running config router isis isp Optional Displays the entire contents of the currently running configuration file or a subset of that file e Verify that nsf appears in the IS IS configuration of the NSF aware device e This example shows the contents of the configuration file for the isp instance only Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Configuring Authentication for IS IS This task explains how to configure authentication for IS IS This task is optional Authentication is available to limit the establishment of adjacencies by using the hello password configuration and to limit the exchange of LSPs by using the LSP password IS IS supports plain text authentication which does not provide security against hackers or other unauthorized users Plain text authentication allows you to configure a password to prevent unauthorized networking devices from forming adjacencies with this router The password is exchanged as plain text and is potentially visible to an agent able to view the IS IS packets IS IS stores a configured password using simple encryption However the plain text form of the password is used in LSPs sequence number protocols SNPs and hello packets which would be visible to a process that can view IS IS packets The passwords can be entered in plain
130. GP or a compatible product to encrypt any sensitive information that you send to Cisco PSIRT can work from encrypted information that is compatible with PGP versions 2 x through 8 x Never use a revoked or an expired encryption key The correct public key to use in your correspondence with PSIRT is the one linked in the Contact Summary section of the Security Vulnerability Policy page at this URL http www cisco com en US products products_security_vulnerability_policy html The link on this page has the current PGP key ID in use Obtaining Technical Assistance Cisco Technical Support provides 24 hour a day award winning technical assistance The Cisco Technical Support amp Documentation website on Cisco com features extensive online support resources In addition if you have a valid Cisco service contract Cisco Technical Assistance Center TAC engineers provide telephone support If you do not have a valid Cisco service contract contact your reseller Cisco Technical Support amp Documentation Website The Cisco Technical Support amp Documentation website provides online documents and tools for troubleshooting and resolving technical issues with Cisco products and technologies The website is available 24 hours a day at this URL http www cisco com techsupport Access to all tools on the Cisco Technical Support amp Documentation website requires a Cisco com user ID and password If you have a valid service contract but
131. IS IS Version 2 specifications detailed in RFC 1195 and the IPv6 IS IS functionality based on the Internet Engineering Task Force IETF IS IS Working Group draft ietf isis ipv6 txt document The following list outlines key features supported in the Cisco IOS XR implementation e Improved configuration syntax and enhanced show commands e Single topology IPv6 e Multitopology e Nonstop forwarding NSF both Cisco proprietary and IETF e Three way handshake e Mesh groups e Multiple IS IS instances e Configuration of a broadcast medium connecting two networking devices as a point to point link IS IS Configuration Grouping Cisco IOS XR groups all of the IS IS configuration in router configuration mode including the portion of the interface configurations associated with IS IS The grouping makes the configuration process clearer and eliminates some of the clutter in the global interface stanza To display the IS IS configuration in its entirety use the show isis interface command The command output displays the running configuration for all configured IS IS instances including the interface assignments and interface attributes Cisco 10S XR Routing Configuration Guide jL RCes Implementing IS IS on Cisco 10S XR Software HZ Information About Implementing IS IS on Cisco 10S XR Software IS IS Interfaces IS IS interfaces can be configured as one of the following types e active advertises connected prefixes and forms adjacen
132. Mode The following example shows how to enter global address family configuration mode RP 0 RPO CPU0 router config router bgp 140 RP 0 RPO CPU0 router config bgp address family ipv4 multicast RP 0 RPO CPUO router config bgp af Neighbor Configuration Mode The following example shows how to enter neighbor configuration mode RP 0 RPO CPU0 router config router bgp 140 RP 0 RPO CPU0 router config bgp neighbor 10 0 0 1 RP 0 RPO CPU0 router config bgp nbr Neighbor Address Family Configuration Mode The following example shows how to enter neighbor address family configuration mode RP 0 RPO CPUO router RP 0 RPO CPU0 router RP 0 RPO CPUO router RP 0 RPO CPUO router config router bgp 140 config bgp neighbor 10 0 0 1 config bgp nbr address family ipv4 unicast config bgp nbr af Neighbor Submode Cisco IOS XR BGP uses a neighbor submode to make it possible to enter configurations without having to prefix every configuration with the neighbor keyword and the neighbor address e Cisco IOS XR software has a submode available for neighbors in which it is not necessary for every command to have a neighbor x x x x prefix In Cisco IOS XR software the configuration is as follows Router config bgp af neighbor 192 23 1 2 Router config bgp nbr remote as 2002 Router config bgp nbr address family ipv4 multicast e An address family configuration submode inside the neighbor configuration subm
133. P 0 RPO CPU0 router config isis if address family ipv6 unicast Specifies the IPv6 address family and enters interface address family configuration mode e This example specifies the unicast IPv6 address family Cisco 10S XR Routing Configuration Guide _ Implementing IS IS on Cisco 10S XR Software Step 11 Step 12 Step 13 Step 14 Step 15 Command or Action How to Implement IS IS on Cisco IOS XR Software Hl Purpose end or commit Example RP 0 RPO CPU0 router config isis if af end or RP 0 RPO CPU0 router config isis if af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session show isis instance instance id interface type instance brief detail level 1 2 Example RP
134. P on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process bgp default local preference value Example RP 0 RPO CPU0 router config bgp bgp default local preference 200 Sets the default local preference value from the default of 100 to 200 making it a more preferable path end or commit Example RP 0 RPO CPU0 router config bgp end or RP 0 RPO CPU0 router config bgp commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain w
135. PF area for MPLS TE Cisco 10S XR Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software Step 5 Step 6 Step 7 How to Implement OSPF on Cisco 10S XR Software W Command or Action Purpose mpls traffic eng router id ip address interface type interface instance Example RP 0 RPO CPU0 router config ospf mpls traffic eng router id loopback 0 Optional Specifies that the traffic engineering router identifier for the node is the IP address associated with a given interface e This IP address is flooded to all nodes in TE LSAs e For all traffic engineering tunnels originating at other nodes and ending at this node you must set the tunnel destination to the traffic engineering router identifier of the destination node because that is the address that the traffic engineering topology database at the tunnel head uses for its path calculation e We recommend that loopback interfaces be used for MPLS TE router ID because they are more stable than physical interfaces area area id Example RP 0 RPO CPU0 router config ospf area 0 Enters area configuration mode and configures an area for the OSPF process e The area id argument can be entered in dotted decimal or IPv4 address notation such as area 1000 or area 0 0 3 232 However you must choose one form or the other for an area interface type instance Example RP 0 RPO CPU0 router config ospf ar interface in
136. PF v2 differences RC 131 CLI inheritance RC 131 configuration neighbors nonbroadcast networks RC 150 SPF throttling RC 170 configuration and operation verifying RC 180 description RC 127 enabling RC 145 functional overview RC 129 instance and router ID RC 134 load balancing RC 141 LSA controlling frequency RC 158 on an OSPF ABR RC 164 types RC 137 neighbors nonbroadcast networks configuring RC 150 policy attach points default originate RC 232 redistribute RC 231 RC 233 routes redistribute RC 166 SPF Shortest Path First throttling configuring RC 170 stub and not so stubby area types configuring RC 147 virtual link description RC 138 ospfv3 area configuration submode dead interval command RC 152 default cost command RC 149 hello interval command RC 152 interface command RC 146 network command RC 152 nssa command RC 149 range command RC 165 stub command RC 149 OSPFv3 Graceful Restart feature RC 141 adjacency RC 143 displaying information RC 186 ospfv3 interface configuration submode log adjacency changes RC 147 neighbor command RC 153 overload bit configuration RC 87 on router RC 89 Cisco 10S XR Routing Configuration Guide P password accept command RC 57 password disable command RC 57 point to point networks RC 135 policy modifying attached RC 235 nonattached RC 235 range command RC 165 receive buffer size command RC 57 redistribute command RC 47 RC 168 redistribute isis command RC
137. PS 1 configure oF vN end or commit router bgp autonomous system number address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast distance bgp external distance internal distance local distance Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp address family ipv4 unicast Enters global address family configuration mode for the IPv4 address family distance bgp external distance internal distance local distance Example RP 0 RPO CPU0 router config bgp af distance bgp 20 20 200 Sets the external internal and local administrative distances to prefer one class of routes over another The higher the value the lower the trust rating The external distance argument is set to 20 the internal distance argument is set to 20 and the local distance argument is set to 200 end or commit Exampl
138. P_3 RP 0 RPO CPUO router config bgp afgrp send community ebgp RP 0 RPO CPU0 router config bgp afgrp send extended community ebgp RP 0 RPO CPU0 router config bgp afgrp capability orf prefix list both RP 0 RPO CPU0 router config bgp afgrp exit RP 0 RPO CPU0 router config bgp session group GROUP_3 RP 0 RPO CPU0 router config bgp sngrp timers 30 90 RP 0 RPO CPU0 router config bgp sngrp exit RP 0 RPO CPU0 router config bgp neighbor group GROUP_1 RP 0 RPO CPU0 router config bgp nbrgrp remote as 1982 RP 0 RPO CPU0 router config bgp nbrgrp use neighbor group GROUP_2 RP 0 RPO CPU0 router config bgp nbrgrp address family ipv4 unicast RP 0 RPO CPU0 router config bgp nbrgrp af exit RP 0 RPO CPU0 router config nbrgrp exit RP 0 RPO CPU0 router config bgp neighbor group GROUP_2 RP 0 RPO CPU0 router config bgp nbrgrp use session group GROUP_3 RP 0 RPO CPU0 router config bgp nbrgrp address family ipv4 unicast RP 0 RPO CPUO router config bgp nbrgrp af use af group GROUP_2 RP 0 RPO CPU0 router config bgp nbrgrp af weight 100 Cisco IOS XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W The following is sample output from the show bgp neighbor group command with the configuration keyword The configuration setting source is shown to the right of each command In the output shown pre
139. R Software HT How to Implement BGP on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Command or Action Purpose configure Example RP 0 RPO CPUO router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPUO router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process neighbor ip address Example RP 0 RPO CPUO 172 168 40 24 router config bgp neighbor Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer shutdown Disables all active sessions for neighbor 172 168 40 24 Example RP 0 RPO CPU0 router config bgp nbr shutdown end Saves configuration changes or A e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RP0 CPU0 router config bgp nbr end cancel or Entering yes saves configuration changes to the RP 0 RP0 CPU0 router config bgp nbr commit running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the c
140. RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Enters neighbor address family configuration mode for the IPv4 address family route reflector client Example RP 0 RPO CPU0 router config bgp nbr af route reflector client Configures the router as a BGP route reflector and configures the neighbor 172 168 40 24 as its client end or commit Example RP 0 RPO CPU0 router config bgp nbr af end or RP 0 RPO CPU0 router config bgp nbr af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Configuring BGP Route Filtering by Route Policy Perform t
141. Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software Step 9 Step 10 Step 11 Step 12 Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose neighbor ip address priority number poll interval seconds cost number or neighbor ipv6 link local address priority number poll interval seconds cost number database filter all Example RP 0 RPO CPU0 router config ospf ar if neighbor 10 20 20 1 priority 3 poll interval 15 or RP 0 RPO CPU0 router config ospf ar if neighbor fe80 3203 a0ff fe9d f3fe Configures the IPv4 address of OSPF neighbors interconnecting to nonbroadcast networks or Configures the link local IPv6 address of OSPFv3 neighbors The ipv6 link local address must be in the form that is specified in RFC 2373 The address is specified in hexadecimal using 16 bit values between colons The priority keyword notifies the router that this neighbor is eligible to become a DR or BDR The priority value should match the actual priority setting on the neighbor router The neighbor priority default value is 0 This keyword does not apply to point to multipoint interfaces The poll interval keyword does not apply to point to multipoint interfaces RFC 1247 recommends that this value be much larger than the hello interval The default is 120 seconds 2 minutes Neighbors with no specific cost configured assumes the cost of the interface base
142. SAs Step 4 show ospf process name area id flood list interface type instance Example RP 0 RPO CPU0 router show ospf 100 flood list interface pos 0 3 0 0 Optional Displays a list of OSPF LSAs waiting to be flooded over an interface Step 5 show ospf process name area id neighbor interface type interface instance neighbor id detail Example RP 0 RPO CPU0 router show ospf 100 neighbor Optional Displays OSPF neighbor information on an individual interface basis Step 6 clear ospf process name process Example RP 0 RPO CPUO router clear ospf 100 process Optional Resets an OSPF router process without stopping and restarting it Step 7 clear ospf process name statistics neighbor interface type interface instance ip address Example RP O0 RPO CPU0 router clear ospf 100 statistics Optional Clears the OSPF statistics of neighbor state transitions Configuring OSPFv3 Graceful Restart This section describes the following tasks for configuring a graceful restart of an OSPFV3 process e Enabling Graceful Restart page RC 182 e Configuring the Maximum Lifetime of a Graceful Restart page RC 182 e Configuring the Minimum Time Required Between Restarts page RC 183 e Configuring the Helper Level of the Router page RC 184 e Displaying Information About Graceful Restart page RC 185 Cisco 10S XR Routing Configuration Guide Implementing OSPF on Cisco 10S XR
143. Software HT How to Implement OSPF on Cisco IOS XR Software Enabling Graceful Restart This section describes how to enable an OSPFV3 graceful restart on the current router By default this feature is disabled SUMMARY STEPS 1 configuration 2 router ospfv3 3 graceful restart DETAILED STEPS Command or Action Purpose Step1 config Enters global configuration mode Example RP 0 RPO CPU0 singlel10 hfr config RP 0 RPO CPU0 single10 hfr config Step2 router ospfv3 process name Enters router configuration mode for OSPFv3 The process name is a WORD that uniquely identifies an OSPF routing process The process name is any alphanumeric string no E le en sae longer than 40 characters without spaces RP 0 RPO CPU0 singlel10 hfr config router ospfv3 test Step3 graceful restart Enable graceful restart on the current router Example RP 0 RPO CPU0 singlel0 hfr config ospfv3 grace ful restart Configuring the Maximum Lifetime of a Graceful Restart This section describes the task of modifying the total time that a router can be in graceful restart mode The default lifetime is 95 seconds The range is 90 3600 seconds SUMMARY STEPS 1 configuration 2 router ospfv3 3 graceful restart lifetime Cisco 10S XR Routing Configuration Guide RC 182 _Implementing OSPF on Cisco 10S XR Software How to Implement OSPF on Cisco 10S XR Software W DETAILED STEPS Command or Action Purpose
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145. XR Multicast Configuration Guide MPC Cisco IOS XR MPLS Configuration Guide ac Cisco IOS XR Modular Quality of Service Configuration Guide RC Cisco IOS XR Routing Configuration Guide sc Cisco IOS XR System Security Configuration Guide SMC Cisco IOS XR System Management Configuration Guide A address family command RC 5 address family command IS IS RC 96 adjacencies tuning RC 113 administrative distance RC 197 advertisement interval command RC 56 aggregate address command RC 44 apply command RC 223 Area Border Routers ABRs RC 134 area command RC 146 attached bit on an IS IS instance RC 90 authentication MD5 OSPFv2 RC 135 route key rollover OSPFv2 RC 136 strategies RC 136 authentication configuring OSPFv2 RC 155 authentication command OSPFv2 RC 156 authentication message digest command RC 162 Autonomous System Boundary Routers ASBRs RC 134 autonomous systems RC 132 backbone area _ RC 133 bestpath algorithm RC 18 INDEX BGP Border Gateway Protocol bestpath algorithm RC 18 configuration grouping RC 5 inheriting RC 7 description RC 1 functional overview RC 2 inheritance monitoring RC 11 local next hop addresses validating RC 4 multiprotocol RC 21 neighbors maximum limits on RC 3 policy attach points dampening RC 225 default originate RC 225 neighbor export RC 226 neighbor import RC 226 network RC 227 redistribute RC 227 show bgp RC 228 table policy RC 229 policy attach points aggregation R
146. a configuration task search online in the Cisco IOS XR software master command index Feature History for Implementing IS IS on Cisco 10S XR Software Release Modification Release 2 0 This feature was introduced on the Cisco CRS 1 Release 3 0 No modification Release 3 2 Support was added for the Cisco XR 12000 Series Router The ability to configure a broadcast medium connecting two networking devices as a point to point link was added Release 3 2 2 Support was added for the multicast intact feature e Prerequisites for Implementing IS IS on Cisco IOS XR Software page RC 84 e Restrictions for Implementing IS IS on Cisco IOS XR Software page RC 84 e Information About Implementing IS IS on Cisco IOS XR Software page RC 84 e How to Implement IS IS on Cisco IOS XR Software page RC 91 e Configuration Examples for Implementing IS IS on Cisco IOS XR Software page RC 122 e Where to Go Next page RC 124 e Additional References page RC 124 Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HI Prerequisites for Implementing IS IS on Cisco 10S XR Software Prerequisites for Implementing IS IS on Cisco 10S XR Software The following are prerequisites for implementing IS IS on Cisco IOS XR software e You must be in a user group associated with a task group that includes the proper task IDs for IS IS commands Task IDs for commands are listed in the Cisco IOS XR Task ID
147. acters router id ipv4 address interface type interface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IPv4 address as the router ID nsf or nsf enforce global Example RP 0 RP0 CPU0 router config ospf nsf or RP 0 RP0 CPU0 router config ospf nsf enforce global Enables OSPF NSF operations e Use the nsf command without the optional enforce and global keywords to abort the NSF restart mechanism on the interfaces of detected non NSF neighbors and allow NSF neighbors to function properly e Use the nsf command with the optional enforce and global keywords if the router is expected to perform NSF during restart However if non NSF neighbors are detected NSF restart is canceled for the entire OSPF process E Cisco IOS XR Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software Step 5 Step 6 Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose nsf interval seconds Example RP 0 RPO CPU0 router config ospf nsf interval 120 Sets Note the minimum time between NSF restart attempts When you use this command the OSPF process must be up for at least 90 seconds before OSPF attempts to perform an NSF restart end or commit Example RP 0 RPO CPU0 router config ospf end or RP 0 RPO CPU0 router confi
148. address family ipv4 ipv6 multicast unicast route policy route policy name in out eo aea YS NN end or commit Cisco IOS XR Routing Configuration Guide RC 238 Implementing Routing Policy on Cisco IOS XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 How to Implement Routing Policy W Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router bgp as number Example RP 0 RPO CPU0 router config router bgp 125 Configures a BGP routing process and enters router configuration mode e The as number argument identifies the autonomous system in which the router resides Valid values are from 0 to 65535 Private autonomous system numbers that can be used in internal networks range from 64512 to 65535 neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 10 0 0 20 Specifies a neighbor IP address address family ipv4 ipv6 multicast unicast Example RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Specifies the address family the version of IP that is in use and either multicast or unicast e Enters address family configuration mode Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HZ How to Implement Routing Policy Command or Action Purpose Step5 route policy policy
149. affic Engineering RC 175 Verifying OSPF Configuration and Operation RC 180 Configuring OSPFv3 Graceful Restart RC 181 Enabling Multicast Intact for OSPFv2 RC 186 Configuration Examples for Implementing OSPF on Cisco IOS XR Software RC 187 Cisco IOS XR for OSPF Version 2 Configuration Example RC 188 CLI Inheritance and Precedence for OSPF Version 2 Example RC 189 MPLS TE for OSPF Version 2 Example RC 190 ABR with Summarization for OSPFv3 Example RC 190 ABR Stub Area for OSPFv3 Example RC 190 ABR Totally Stub Area for OSPFv3 Example RC 191 Route Redistribution for OSPFv3 Example RC 191 Virtual Link Configured Through Area 1 for OSPFv3 Example RC 191 Virtual Link Configured with MD5 Authentication for OSPF Version 2 Example RC 192 Where to Go Next RC 192 Additional References RC 193 Related Documents RC 193 Standards RC 193 MIBs RC 193 RFCs RC 193 Technical Assistance RC 194 Implementing and Monitoring RIB on Cisco IOS XR Software RC 195 Contents RC 195 Prerequisites for Implementing RIB on Cisco IOS XR Software RC 196 Information About RIB Configuration RC 196 Overview of RIB RC 196 RIB Data Structures in BGP and Other Protocols RC 196 RIB Administrative Distance RC 197 Cisco 10S XR Routing Configuration Guide E E Contents RIB Support for IPv4 and IPv6 RC 197 How to Deploy and Monitor RIB RC 198 Verifying RIB Configuration Using the Routing Table RC 198 Verifying Networking and Routing Problems RC 198 Co
150. ail level 1 2 Example RP 0 RPO CPU0 router show isis interface POSO 1 0 1 Step15 show isis instance instance id topology Optional Displays a list of connected routers in all areas systemid system id level 1 2 summary Example RP 0 RPO CPU0 router show isis topology Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Configuring Multitopology for IS IS This task explains how to configure multitopology IS IS This task is optional Multitopology is configured in much the same way as the single topology for IPv4 and IPv6 address families The single topology command is omitted invoking the default multitopology behavior SUMMARY STEPS 11 12 13 14 15 son SF os gt configure interface type instance ipv4 address address mask or ipv6 address ipv6 prefix prefix length eui 64 or ipv6 address ipv6 address prefix length link local or ipv6 enable exit router isis instance id net network entity title interface type instance address family ipv4 unicast exit address family ipv6 unicast end or commit show isis instance instance id interface type number brief detail level 1 2 show isis instance instance id topology systemid system id level 1 2 ipv4 ipv6 summary unicast show isis instance instance id adjacency level 1 2
151. ains a list of shortest paths to known destinations through specific router interface ports OSPF is the IGP of choice because it scales to large networks It uses areas to partition the network into more manageable sizes and to introduce hierarchy in the network A router is attached to one or more areas in a network All of the networking devices in an area maintain the same complete database information about the link states in their area only They do not know about all link states in the network The agreement of the database information among the routers in the area is called convergence At the intradomain level OSPF can import routes learned using Intermediate System to Intermediate System IS IS OSPF routes can also be exported into IS IS At the interdomain level OSPF can import routes learned using Border Gateway Protocol BGP OSPF routes can be exported into BGP Unlike Routing Information Protocol RIP OSPF does not provide periodic routing updates On becoming neighbors OSPF routers establish an adjacency by exchanging and synchronizing their databases After that only changed routing information is propagated Every router in an area advertises the costs and states of its links sending this information in an LSA This state information is sent to all OSPF neighbors one hop away All the OSPF neighbors in turn send the state information unchanged This flooding process continues until all devices in the area have the same link st
152. al from the neighbor group is used because it is not configured directly on the neighbor and no session group is used Cisco IOS XR Routing Configuration Guide RC 8 _ mplementing BGP on Cisco 10S XR Software P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C HAADA AA AAAA DA HAA AA AAAA DA eT a SP ORE ES SE a FL 6 3 eS OS eas Information About Implementing BGP on Cisco IOS XR Software router config router bgp 150 router config bgp session group AS_2 router config bgp sngrp advertisement interval 20 router config bgp sngrp exit router router config bgp neighbor group AS_1 config bgp nbrgrp advertisement interval 15 router config bgp nbrgrp exit router config bgp neighbor 192 168 1 1 router config bgp nbr remote as 1 router config bgp nbr use neighbor group AS_1 The following output from the show bgp neighbors command shows that the advertisement interval used is 15 seconds RP 0 BGP neighbor is 192 168 2 2 te router ID 0 0 0 0 state t read 00 00 00 Received 0 messages Sent 0 messages Remo BGP Las RPO CPU0 router show bgp neighbors 192 168 1 1 remote AS 1 local AS 140 external link Idle hold time is 180 keepalive interval is 60 seconds 0 notifications 0 in queue 0 notifications 0 in queue Minimum time be
153. amily ipv6 unicast Specifies the IPv6 address family and enters router address family configuration mode e This example specifies the unicast IPv6 address family single topology Example RPO 0 RPO CPU0 router config isis af single topology Optional Configures the link topology for IPv4 when IPv6 is configured e The single topology command is valid only in IPv6 submode The command instructs IPv6 to use the single topology rather than the default configuration of a separate topology in the multitopology mode e See the Single Topology IPv6 Support section on page RC 87 for more information exit Example RP 0 RPO CPU0 router config isis af exit Exits router address family configuration mode and returns the router to router configuration mode interface type instance Example RP 0 RPO CPU0 router config isis interface POS 0 1 0 3 Enters interface configuration mode Cisco 10S XR Routing Configuration Guide _ Implementing IS IS on Cisco 10S XR Software How to Implement IS IS on Cisco IOS XR Software Hl Command or Action Purpose Step11 circuit type level 1 level 1 2 Optional Configures the type of adjacency level 2 only i T e The default circuit type is the configured system type configured through the is type command Example e Typically the circui b fi Ahn RP 0 RPO CPU0 router config isis if ypical y t e circuit type must be co
154. an AS_SEQUENCE then the neighbor AS is the first AS number in the AS_SEQUENCE and the MED is compared with other paths that have the same neighbor AS Note if no MED attribute was received with the path then the MED is considered to be 0 unless the bgp bestpath med missing as worst command is configured In that case if no MED attribute was received the MED is considered to be the highest possible value If one path is received from an external peer and the other is received from an internal or confederation peer the path from the external peer is chosen See Section 9 1 2 2d of draft ietf idr bgp4 24 txt If the paths have different IGP metrics to their next hops the path with the lower IGP metric is chosen See Section 9 1 2 2e of draft ietf idr bgp4 24 txt If all path parameters in steps 1 through 10 are the same then the router IDs are compared If the path was received with an originator attribute then that is used as the router ID to compare otherwise the router ID of the neighbor from which the path was received is used If the paths have different router IDs the path with the lower router ID is chosen Note where the originator is used as the router ID it is possible to have two paths with the same router ID It is also possible to have two BGP sessions with the same peer router and therefore receive two paths with the same router ID See Section 9 1 2 2f of draft ietf idr bgp4 24 txt If the paths have different cl
155. an error to the user Likewise a valid policy in use at an attach point cannot be modified in such a way as to introduce an attempt to modify a nonexistent attribute or to compare against a nonexistent attribute The verifiers test for nonexistent attributes and reject such a configuration attempt Policy Statements Remark Four types of policy statements exist remark disposition drop and pass action set and if comparator A remark is text attached to policy configuration but otherwise ignored by the policy language parser Remarks are useful for documenting parts of a policy The syntax for a remark is text that has each line prepended with a pound sign This is a simple one line remark This is a remark comprising multiple lines EE In general remarks are used between complete statements or elements of a set Remarks are not supported in the middle of statements or within an inline set definition Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy Disposition Unlike traditional comments in the CLI RPL remarks persist through reboots and when configurations are saved to disk or a TFTP server and then loaded back onto the router By default a route is dropped at the end of policy processing unless either the policy modifies a route attribute or it passes the route by means of an explicit pass stat
156. and send buffer size command RC 57 timers command RC 57 ttl security command RC 57 update source command RC 57 bgp neighbor submode RC 5 See bgp neighbor command shutdown command RC 70 use command RC 58 bgp redistribute internal command RC 45 bgp router submode RC 5 bgp bestpath as path ignore command RC 40 bgp bestpath compare routerid command RC 4 bgp bestpath med always command RC 40 bgp bestpath med confed command RC 40 bgp bestpath med missing as worst command RC 40 bgp confederation identifier command RC 32 bgp confederation peers command RC 33 bgp default local preference command RC 36 bgp redistribute internal command RC 45 default metric command RC 37 See router bgp command timers bgp command RC 34 bgp session group submode RC 6 BGP update groups example RC 77 Cc circuit type command RC 97 clear bgp flap statistics command RC 50 clear bgp flap statistics reexp command RC 51 clear bgp flap statistics route policy command RC 51 clear bgp soft in command RC 71 clear bgp soft out command RC 72 clear ospf command RC 181 clear ospfv3 command RC 181 csnp interval command RC 104 D dampening route RC 23 dead interval command RC 152 default address family RC 15 default cost command RC 149 default information originate command RC 121 default metric command RC 37 description command RC 56 distance bgp command RC 54 Cisco 10S XR Routing Configuration Guide distance command RC 121 d
157. anges Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Step 8 show isis instance instance id mpls traffic eng tunnel Example RP 0 RPO CPU0 router show isis instance isp mpls traffic eng tunnel Optional Displays MPLS TE tunnel information Step 9 show isis instance instance id mpls traffic eng adjacency log Example RP O0 RPO CPU0 router show isis instance isp mpls traffic eng adjacency log Optional Displays a log of MPLS TE IS IS adjacency changes Step 10 show isis instance instance id mpls traffic eng advertisements Example RP 0 RPO CPU0 router show isis instance isp mpls traffic eng advertisements Optional Displays the latest flooded record from MPLS TE Cisco IOS XR Routing Configuration Guide _ Implementing IS IS on Cisco 10S XR Software How to Implement IS IS on Cisco IOS XR Software H
158. anges to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Redistributing iBGP Routes into IGP Perform this task to redistribute iBGP routes into an Interior Gateway Protocol IGP such as Intermediate System to Intermediate System IS IS or Open Shortest Path First OSPF Note Use of the bgp redistribute internal command requires the clear route command to be issued to reinstall all BGP routes into the IP routing table A Caution Use this command with caution Redistributing iBGP routes into IGPs may cause routing loops to form within an autonomous system Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software SUMMARY STEPS 1 configure router bgp autonomous system number bgp redistribute internal PF eS N end or commit DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Command or Action How to Implement BGP on Cisco IOS XR Software Hl Purpose configure Example RP 0 RPO CPU0 router
159. ar bgp ipv4 ipv all unicast Soft resets a BGP neighbor multicast all ip address as number external soft out e The keyword resets all BGP neighbors e The ip address argument specifies the address of the Example neighbor to be reset RP 0 RPO CPU0 router clear bgp ipv4 unicast e The as number argument specifies that all neighbors AEN e2 ORS OUR that match the autonomous system number be reset e The external keyword specifies that all external neighbors are reset Resetting Neighbors Using BGP Hard Reset Perform this task to reset neighbors using a hard reset A hard reset removes the TCP connection to the neighbor removes all routes received from the neighbor from the BGP table and then re establishes the session with the neighbor If the graceful keyword is specified the routes from the neighbor are not removed from the BGP table immediately but are marked as stale After the session is re established any stale route that has not been received again from the neighbor is removed SUMMARY STEPS 1 clear bgp ip address as number external graceful DETAILED STEPS Command or Action Purpose Step1 clear bgp ip address as number Clears a BGP neighbor The graceful keyword specifies a external graceful graceful restart Example RP 0 RP0 CPU0 router clear bgp 10 0 0 3 Cisco IOS XR Routing Configuration Guide RC 72 _ mplementing BGP on Cisco 10S XR Software
160. ase level 1 2 detail summary verbose 1sp id Example RP 0 RPO CPU0 router show isis database level 1 Optional Displays the IS IS LSP database show isis instance instance id lsp log level 1 23 Example RP O0 RPO CPU0 router show isis lsp log Optional Displays LSP log information show isis database log level 1 2 Example RP O0 RPO CPU0 router show isis database log level 1 Optional Display IS IS database log information Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Configuring Nonstop Forwarding for IS IS This task explains how to configure your router with NSF that allows the Cisco IOS XR software to resynchronize the IS IS link state database with its IS IS neighbors after a process restart The process restart could be due to an e RP failover for a warm restart e Simple process restart due to an IS IS reload or other administrative request to restart the process e IS IS software upgrade In all cases NSF mitigates link flaps and loss of user sessions This task is optional SUMMARY STEPS 1 configure 2 router isis instance id 3 nsf cisco ietf 4 nsf interface expires number 5 nsf interface timer seconds 6 nsf lifetime seconds 7 end or commit 8 show running config command DETAILED STEPS Command or Action Purpose Step1 configure Ente
161. asis Cisco 10S XR Routing Configuration Guide JL Rc 129 Implementing OSPF on Cisco 10S XR Software HZ Information About Implementing OSPF on Cisco 10S XR Software OSPF typically requires coordination among many internal routers Area Border Routers ABRs which are routers attached to multiple areas and Autonomous System Border Routers ASBRs that export reroutes from other sources for example IS IS BGP or static routes into the OSPF topology At a minimum OSPF based routers or access servers can be configured with all default parameter values no authentication and interfaces assigned to areas If you intend to customize your environment you must ensure coordinated configurations of all routers Key Features Supported in the Cisco IOS XR OSPF Implementation The Cisco IOS XR implementation of OSPF conforms to the OSPF Version 2 and OSPF Version 3 specifications detailed in the Internet RFC 2328 and RFC 2740 respectively The following key features are supported in the Cisco IOS XR implementation Hierarchy CLI hierarchy is supported Inheritance CLI inheritance is supported Stub areas Definition of stub areas is supported NSF Nonstop forwarding is supported SPF throttling Shortest path first throttling feature is supported LSA throttling LSA throttling feature is supported Fast convergence SPF and LSA throttle timers are set configuring fast convergence The OSPF LSA throttling feature provi
162. atabase information are not check pointed An OSPFV3 process rebuilds adjacencies after it restarts To ensure consistent databases after a restart the OSPFv3 configuration must be identical to the configuration before the restart This requirement applies to self originated information in the local database A graceful restart can fail if configurations change during the operation In this case data forwarding would be affected OSPFv3 resumes operation by regenerating all its LSAs and resynchronizing its database with all its neighbors Although IPv6 FIB tables remain unchanged during a graceful restart these tables eventually mark the routes as stale through the use of a holddown timer Enough time is allowed for the protocols to rebuild state information and converge The router on which OSPFV3 is restarting must send OSPFV3 hellos within the dead interval of the process restart Protocols must be able to retain adjacencies with neighbors before the adjacency dead timer expires The default for the dead timer is 40 seconds If hellos do not arrive on the adjacency before the dead timer expires the router takes down the adjacency The OSPFv3 Graceful Restart feature does not function properly if the dead timer is configured to be less than the time required to send hellos after the OSPFv3 process restarts Simultaneous graceful restart sessions on multiple routers are not supported on a single network segment If a router determines that mul
163. ate database To determine the best route to a destination the software sums all of the costs of the links in a route to a destination After each router has received routing information from the other networking devices it runs the shortest path first SPF algorithm to calculate the best path to each destination network in the database The networking devices running OSPF detect topological changes in the network flood link state updates to neighbors and quickly converge on a new view of the topology Each OSPF router in the network soon has the same topological view again OSPF allows multiple equal cost paths to the same destination Since all link state information is flooded and used in the SPF calculation multiple equal cost paths can be computed and used for routing On broadcast and nonbroadcast multiaccess NBMA networks the designated router DR or backup DR performs the LSA flooding On point to point networks flooding simply exits an interface directly to a neighbor OSPF runs directly on top of IP it does not use TCP or User Datagram Protocol UDP OSPF performs its own error correction by means of checksums in its packet header and LSAs In OSPFV3 the fundamental concepts are the same as OSPF Version 2 except that support is added for the increased address size of IPv6 New LSA types are created to carry IPv6 addresses and prefixes and the protocol runs on an individual link basis rather than on an individual P subnet b
164. ation Guide E Implementing and Monitoring RIB on Cisco 10S XR Software W Additional References RFCs RFCs Title No new or modified RFCs are supported by this feature and support for existing RFCs has not been modified by this feature Technical Assistance Description Link The Cisco Technical Support website contains thousands of pages of searchable technical content including links to products technologies solutions technical tips and tools Registered Cisco com users can log in from this page to access even more content http www cisco com techsupport Cisco 10S XR Routing Configuration Guide amp Implementing Routing Policy on Cisco 10S XR Software A routing policy instructs the router to inspect routes filter them and potentially modify their attributes as they are accepted from a peer advertised to a peer or redistributed from one routing protocol to another Routing protocols make decisions to advertise aggregate discard distribute export hold import redistribute and otherwise modify routes based on configured routing policy The routing policy language RPL has been designed to provide a single straightforward language in which all routing policy needs can be expressed RPL was designed to support large scale routing configurations It greatly reduces the redundancy inherent in previous routing policy configuration methods RPL has been designed to streamline r
165. butes on the aggregated route In the policy language setting attributes on the aggregated route is controlled by normal action operations In the following example the aggregate address 10 0 0 0 8 is generated if there are any component routes in the range 10 0 0 0 8 ge 8 le 25 except for 10 2 0 0 24 Because summary only is not set all components of the aggregate are advertised However the specific component 10 1 0 0 are suppressed route policy sample if destination in 10 0 0 0 8 ge 8 le 25 then set community 10 33 endif if destination in 10 2 0 0 24 then drop endif if destination in 10 1 0 0 24 then suppress route endif end policy Cisco 10S XR Routing Configuration Guide RC 224 Implementing Routing Policy on Cisco IOS XR Software Dampening Default Originate Information About Implementing Routing Policy i router bgp 2 address family ipv4 aggregate address 10 0 0 0 8 policy sample The dampening attach point controls the default route dampening behavior within BGP Unless overridden by a more specific policy on the associate peer all routes in BGP apply the associated policy to set their dampening attributes The following policy sets dampening values for BGP IPv4 unicast routes Those routes that are more specific than a 25 take longer to recover after they have been dampened than routes that are less specific than 25 route policy sample_damp if destination in 0 0 0 0 0 ge 25 then
166. cast safi all ip address mask longer prefixes Example RP O0 RPO CPU0 router show route ipv4 unicast 192 168 111 8 longer prefixes Displays the current routes in RIB that share a given number of bits with a given network Step7 show route afi all ipv4 ipv6 unicast multicast safi all next hop ip address Example RP O0 RPO CPU0 router show route ipv4 unicast next hop 192 168 1 34 Displays the next hop gateway or host to a destination address Configuration Examples for RIB Monitoring RIB is not configured separately for the Cisco IOS XR system RIB computes connectivity of the router with other nodes in the network based on input from the routing protocols RIB may be used to monitor and troubleshoot the connections between RIB and its clients but it is essentially used to monitor routing connectivity between the nodes in a network This section contains displays from the show commands used to monitor that activity The following sample output is provided e Output of show route Command Example page RC 200 e Output of show route backup Command Example page RC 201 e Output of show route best local Command Example page RC 201 e Output of show route connected Command Example page RC 201 e Output of show route local Command Example page RC 201 e Output of show route longer prefixes Command Example page RC 202 e Output of show route next hop Command Example page RC 202 Output of show route Command
167. ch either soft reconfiguration is configured or the BGP route refresh capability has been negotiated The following example shows how to receive routes from neighbor 10 0 0 1 Any routes received with the community 3 100 have their local preference set to 100 and their community tag set to 2 666 All other routes received from this peer have their local preference set to 200 and their community tag set to 2 200 route policy sample_import if community matches any 3 100 then set local preference 100 set community 2 666 else set local preference 200 set community 2 200 endif end policy Cisco 10S XR Routing Configuration Guide RC 226 Implementing Routing Policy on Cisco IOS XR Software Network Redistribute Information About Implementing Routing Policy i router bgp 2 neighbor 10 0 0 1 remote as 3 address family ipv4 unicast route policy sample_import in The network attach point controls the injection of routes from the RIB into BGP A route policy attached at this point is able to set any of the valid BGP attributes on the routes that are being injected The following example shows a route policy attached at the network attach point that sets the well known community no export for any routes more specific than 24 route policy NetworkControl if destination in 0 0 0 0 0 ge 25 then set community no export additive endif end policy router bgp 2 address family ipv4 unicast network 172 16 0 5 27 rou
168. ch of the following LSA types has a different purpose Router LSA Type 1 Describes the links that the router has within a single area and the cost of each link These LSAs are flooded within an area only The LSA indicates if the router can compute paths based on quality of service QoS whether it is an ABR or ASBR and if it is one end of a virtual link Type 1 LSAs are also used to advertise stub networks Network LSA Type 2 Describes the link state and cost information for all routers attached a multiaccess network segment This LSA lists all the routers that have interfaces attached to the network segment It is the job of the designated router of a network segment to generate and track the contents of this LSA Summary LSA for ABRs Type 3 Advertises internal networks to routers in other areas interarea routes Type 3 LSAs may represent a single network or a set of networks aggregated into one prefix Only ABRs generate summary LSAs Summary LSA for ASBRs Type 4 Advertises and ASBR and the cost to reach it Routers that are trying to reach an external network use these advertisements to determine the best path to the next hop ABRs generate Type 4 LSAs Autonomous system external LSA Type 5 Redistributes routes from another autonomous system usually from a different routing protocol into OSPF Link State Advertisement Types for OSPFv3 Each of the following LSA types has a different purpose Router LSA Type 1
169. ciates one or more interfaces to the area Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco 10S XR Software Command or Action Purpose Step7 ena Saves configuration changes or i e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RP0 CPU0 router config ospf ar if end cancel or RP 0 RPO CPU0 router config ospf ar if commit Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Step8 show ospf process name Optional Displays SPF throttling timers or show ospfv3 process name Example RP 0 RPO CPU0 router show ospf 1 or RP 0 RPO CPUO router show ospfv3 2 Examples Cisco 10S XR Routing Configuration Guide In the following example the show ospf EXEC command is used to verify that the initial SPF schedu
170. cies This is the default for interfaces e passive advertises connected prefixes but does not form adjacencies The passive command is used to configure interfaces as passive Passive interfaces should be used sparingly for important prefixes such as loopback addresses that need to be injected into the IS IS domain If many connected prefixes need to be advertised then the redistribution of connected routes with the appropriate policy should be used instead e suppressed does not advertise connected prefixes but forms adjacencies The suppress command is used to configure interfaces as suppressed e shutdown does not advertise connected prefixes and does not form adjacencies The shutdown command is used to disable interfaces without removing the IS IS configuration Multitopology Configuration Cisco IOS XR software supports multitopology for IPv6 IS IS unless single topology is explicitly configured in IPv6 address family configuration mode Ss Note IS IS supports IP routing and not Open Systems Interconnection OSI Connectionless Network Service CLNS routing IPv6 Routing and Configuring IPv6 Addressing By default IPv6 routing is disabled in the Cisco IOS XR software To enable IPv6 routing you must assign IPv6 addresses to individual interfaces in the router using the ipv6 enable or ipv6 address command See the Network Stack IPv4 and IPv6 Commands on Cisco IOS XR Software module of the Cisco IOS XR IP Addresses and Ser
171. co IOS XR Software W BGP Router Identifier For BGP sessions between neighbors to be established BGP must be assigned a router ID The router ID is sent to BGP peers in the OPEN message when a BGP session is established BGP attempts to obtain a router ID in the following ways in order of preference e By means of the address configured using the bgp router id command in router configuration mode e By assigning a primary IPv4 address to the interface specified using the bgp router id command in router configuration mode amp Note If the specified interface does not have an IPv4 address or is not up BGP will fail to obtain a router ID e By using the address specified with the router id command in global configuration mode if the router is booted with the saved router id command and if the ID from this command is available when the last saved loopback configuration is applied e By using the primary IPv4 address on the interface specified with the router id command in global configuration mode if the box is booted with the saved router id command in global configuration mode and if the router ID is up by the time all saved loopback configurations are applied e By using the highest IPv4 address on a loopback interface in the system if the router is booted with saved loopback address configuration e By using the primary IPv4 address of the first loopback address that gets configured if there are not any in the saved configura
172. command for details Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up Down St PfxRcd 10 0 101 2 0 2 0 0 0 0 0 00 00 00 Idle Address Family IPv6 Unicast BGP router identifier 10 0 0 1 local AS number 1 BGP generic scan interval 60 secs BGP main routing table version 2 BGP scan interval 60 secs BGP is operating in STANDALONE mode Process RecvTblVer bRIB RIB SendTblVer Speaker 2 2 2 Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up Down St PfxRcd 2222822 0 2 920 918 2 0 0 15 15 11 1 2222334 0 3 0 0 0 0 0 00 00 00 Idle Address Family IPv6 Multicast BGP router identifier 10 0 0 1 local AS number 1 BGP generic scan interval 60 secs BGP main routing table version 1 BGP scan interval 60 secs BGP is operating in STANDALONE mode Process RecvTblVer bRIB RIB SendTblVer Speaker 1 1 Some configured eBGP neighbors do not have both inbound and outbound policies configured for IPv6 Multicast address family These neighbors will default to sending and or receiving no routes and are marked with in the output below Use the show bgp neighbor lt nbr_address gt command for details Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up Down St PfxRcd 2222 2 0 2 920 918 0 0 0 15 15 11 0 2222 4 0 3 0 0 0 0 0 00 00 00 Idle Cisco 10S XR Routing Configuration Guide RCT Implementing BGP on Cisco IOS XR Software W Information About Implementing BGP on Cisco 10S XR Software Table Policy The table
173. committed changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Step 6 Step 7 Step 8 Step 9 Step 10 Step 11 Command or Action Purpose show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics Example RP O0 RPO CPU0 router show bgp flap statistics Displays BGP flap statistics for all paths show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics regexp regular expression Example RP 0 RPO CPU0 router show bgp flap statistics regexp _1 Displays BGP flap statistics for all paths that match the regular expression _1 show bgp ipv4 unicast multicast all i
174. committed changes found commit them before exiting yes no cancel1 cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuring a Floating Static Route This task explains how to configure a floating static route SUMMARY STEPS 1 configure 2 route ipv4 ipv6 unicast multicast prefix mask ip address interface type interface instance distance tag tag permanent Cisco 10S XR Routing Configuration Guide E Implementing Static Routes on Cisco IOS XR Software HZ How to Implement Static Routes on Cisco 10S XR Software 3 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Example RP O0 RPO CPU0 router configure Enters global configuration mode Step 2 route ipv4 ipv6 unicast multicast prefix mask ip address interface type interface instance distance tag tag permanent Example RP 0 RPO CPU0 router config route ipv6 unicast 200
175. configurations The inherited configuration can be overridden if you directly configure commands for the neighbor or configure session groups or address family groups through the use command From neighbor group configuration mode you can configure address family independent parameters for the neighbor group Use the address family command when in the neighbor group configuration mode After specifying the neighbor group name using the neighbor group command you can assign options to the neighbor group SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 neighbor group name 4 remote as autonomous system number 5 advertisement interval seconds 6 description text 7 dmz link bandwidth 8 ebgp multihop ftl value 9 local as autonomous system number 10 password clear encrypted password 11 password disable 12 receive buffer size socket size bgp size 13 send buffer size socket size bgp size 14 timers keepalive hold time 15 ttl security 16 update source interface type interface number 17 exit 18 neighbor ip address 19 use neighbor group group name 20 end or commit Cisco 10S XR Routing Configuration Guide Lrs Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Command or Action Purpose configure Example RP 0 RPO CPU0 router c
176. configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process bgp redistribute internal Example RP 0 RPO CPU0 router config bgp bgp redistribute internal Allows the redistribution of iBGP routes into an IGP such as IS IS or OSPF end or commit Example RP 0 RPO CPU0 router config bgp end or RP 0 RPO CPU0 router config bgp commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Redistributing Prefixe
177. customer case studies certification and training information and links to scores of in depth online resources You can access Packet magazine at this URL http www cisco com packet iQ Magazine is the quarterly publication from Cisco Systems designed to help growing companies learn how they can use technology to increase revenue streamline their business and expand services The publication identifies the challenges facing these companies and the technologies to help solve them using real world case studies and business strategies to help readers make sound technology investment decisions You can access iQ Magazine at this URL http www cisco com go iqmagazine or view the digital edition at this URL http ciscoiq texterity com ciscoiq sample Internet Protocol Journal is a quarterly journal published by Cisco Systems for engineering professionals involved in designing developing and operating public and private internets and intranets You can access the Internet Protocol Journal at this URL http www cisco com ipj Networking products offered by Cisco Systems as well as customer support services can be obtained at this URL http www cisco com en US products index html Networking Professionals Connection is an interactive website for networking professionals to share questions suggestions and information about networking products and technologies with Cisco experts and other networking professionals Join a discussion a
178. cy Example RC 243 Translating Cisco IOS Route Maps to Cisco IOS XR Routing Policy Language Example RC 244 Additional References RC 244 Related Documents RC 244 Standards RC 244 MIBs RC 245 RFCs RC 245 Technical Assistance RC 245 Implementing Static Routes on Cisco IOS XR Software RC 247 Contents RC 247 Prerequisites for Implementing Static Routes on Cisco IOS XR Software RC 248 Information About Implementing Static Routes on Cisco IOS XR Software RC 248 Static Route Functional Overview RC 248 Default Administrative Distance RC 248 Directly Connected Routes RC 249 Recursive Static Routes RC 249 Fully Specified Static Routes RC 250 Floating Static Routes RC 250 How to Implement Static Routes on Cisco IOS XR Software RC 250 Configuring a Static Route RC 250 Configuring a Floating Static Route RC 251 Changing the Maximum Number of Allowable Static Routes RC 253 Configuration Examples RC 255 Configuring Traffic Discard Example RC 255 Configuring a Fixed Default Route Example RC 255 Configuring a Floating Static Route Example RC 255 Where to Go Next RC 255 Additional References RC 256 Related Documents RC 256 Standards RC 256 MIBs RC 256 RFCs RC 256 Technical Assistance RC 256 Cisco 10S XR Routing Configuration Guide E E Contents Cisco IOS XR Routing Configuration Guide Preface This is the preface for the Cisco IOS XR Routing Configuration Guide The preface contains the following sections e
179. cy sample with the reference to an undefined policy bar at an inbound BGP policy using the neighbor 1 2 3 4 address family ipv4 unicast policy sample in command the configuration attempt is rejected because the policy bar does not exist Likewise you cannot remove a route policy or set that is currently in use at an attach point because this removal would result in an undefined reference An attempt to remove a route policy or set that is currently in use results in an error message to the user A condition exists that is referred to as a null policy in which the policy bar exists but has no statements actions or dispositions in it In other words the policy bar does exist as follows route policy bar end policy This is a valid policy block It effectively forces all routes to be dropped because it is a policy block that never modifies a route nor does it include the pass statement Thus the default action of drop for the policy block is followed E Cisco IOS XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy i Attached Policy Modification Policies that are in use do on occasion need to be modified Traditionally configuration changes are done by completely removing the relevant configuration and then re entering it However this allows for a window of time in which no policy is attached and the default action takes place RPL provides a mec
180. d address family ipv4 ipv6 unicast Example RP 0 RPO CPU0 router config isis address family ipv6 unicast Specifies the IPv4 or IPv6 address family and enters router address family configuration mode e This example specifies the unicast IPv6 address family spf interval initial wait initial secondary wait secondary maximum wait maximum level 1 2 Example RP 0 RPO CPU0 router config isis af spf interval initial wait 10 maximum wait 30 Optional Controls the minimum time between successive SPF calculations e This value imposes a delay in the SPF computation after an event trigger and enforces a minimum elapsed time between SPF runs e If this value is configured too low the router can lose too many CPU resources when the network is unstable e Configuring the value too high delays changes in the network topology that result in lost packets e The SPF interval does not apply to the running of the ISPF because that algorithm runs immediately on receiving a changed LSP ispf startup delay seconds level 1 2 Example RP 0 RP0 CPU0 router config isis af ispf Optional Configures incremental IS IS ISPF to calculate network topology ispf startup delay seconds level 1 2 Example RP 0 RP0 CPU0 router config isis af ispf startup delay 600 Optional Configures the time delay between the starting of the IS IS instance and the activation of ISPF
181. d in order of precedence as follows 1 Ifthe item is configured directly on the neighbor that value is used In the example that follows the advertisement interval is configured both on the neighbor group and neighbor configuration and the advertisement interval being used is from the neighbor configuration RP 0 RPO CPU0 router config router bgp 140 RP 0 RPO CPU0 router config bgp neighbor group AS_1 RP 0 RPO CPU0 router config bgp nbrgrp advertisement interval 15 RP 0 RPO CPU0 router config bgp nbrgrp exit RP 0 RPO CPU0 router config bgp neighbor 10 1 1 1 RP 0 RPO CPU0 router config bgp nbr remote as 1 RP 0 RPO CPU0 router config bgp nbr use neighbor group AS_1 RP 0 RPO CPU0 router config bgp nbr advertisement interval 20 The following output from the show bgp neighbors command shows that the advertisement interval used is 20 seconds RP 0 RPO CPU0 router show bgp neighbors 10 1 1 1 BGP neighbor is 10 1 1 1 remote AS 1 local AS 140 external link Remote router ID 0 0 0 0 BGP state Idle Last read 00 00 00 hold time is 180 keepalive interval is 60 seconds Received 0 messages 0 notifications 0 in queue Sent 0 messages 0 notifications 0 in queue Minimum time between advertisement runs is 20 seconds For Address Family IPv4 Unicast BGP neighbor version 0 Cisco 10S XR Routing Configuration Guide Ea Implementing BGP on Cisco IOS XR Software HZ Information About
182. d on the cost command On point to multipoint interfaces cost number is the only keyword and argument combination that works The cost keyword does not apply to NBMA networks The database filter keyword filters outgoing LSAs to an OSPF neighbor If you specify the all keyword incoming and outgoing LSAs are filtered Use with extreme caution because filtering might cause the routing topology to be seen as entirely different between two neighbors resulting in black holing of data traffic or routing loops Repeat Step 9 for all neighbors on the interface exit Example RP 0 RPO CPU0 router config ospf ar if exit Enters area configuration mode interface type instance Example RP 0 RPO CPU0 router config ospf ar interface POS 0 3 0 1 Enters interface configuration mode and associates one or more interfaces for the area configured in Step 4 In this example the interface inherits the nonbroadcast network type and the hello and dead intervals from the areas because the values are not set at the interface level Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software Step 13 Command or Action Purpose neighbor ip address priority number poll interval seconds cost number database filter all or neighbor ipv6 link local address priority number poll interval seconds cost number da
183. d policies in a modular form Common blocks of policy can be defined and maintained independently These common blocks of policy can then be applied from other blocks of policy to build complete policies This capability reduces the amount of configuration information that needs to be maintained In addition these common blocks of policy can be parameterized This parameterization allows for policies that share the same structure but differ in the specific values that are set or matched against to be maintained as independent blocks of Cisco 10S XR Routing Configuration Guide Re Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy Hi policy For example three policies that are identical in every way except for the local preference value they set can be represented as one common parameterized policy that takes the varying local preference value as a parameter to the policy The policy language introduces the notion of sets Sets are containers of similar data that can be used in route attribute matching and setting operations Four set types exist prefix sets community sets as path sets and extcommunity sets These sets hold groupings of IPv4 or IPv6 prefixes community values AS path regular expressions and extended community values respectively Sets are simply containers of data Most sets also have an inline variant An inline set allows for small enumerations of values to be used
184. d recalculation of LSPs can cause an increased CPU load on the local router Further the flooding of these recalculated LSPs to the other Intermediate Systems in the network causes increased traffic and can result in other routers having to spend more time running route calculations lsp mtu bytes level 1 2 Example RP 0 RPO CPU0 router config isis lsp mtu 1300 Optional Sets the maximum transmission unit MTU size of LSPs max lsp lifetime seconds level 1 2 Example RP 0 RP0 CPU0 router config isis max lsp lifetime 11000 Optional Sets the initial lifetime given to an LSP originated by the router e This is the amount of time that the LSP persists in the database of a neighbor unless the LSP is regenerated or refreshed Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Command or Action Purpose Step8 ignore lsp errors disable Example RP 0 RPO CPU0 router config isis ignore lsp errors disable Optional Sets the router to purge LSPs received with checksum errors Step 9 interface type instance Example RP 0 RPO CPU0 router config isis interface POS 0 1 0 3 Enters interface configuration mode Step10 1sp interval milliseconds level 1 2 Optional Configures the amount of time between each LSP sent on an interface Example RP 0 RPO CPU0 router c
185. d resources your service request is assigned to a Cisco engineer The TAC Service Request Tool is located at this URL http www cisco com techsupport servicerequest For S1 or S2 service requests or if you do not have Internet access contact the Cisco TAC by telephone S1 or S2 service requests are those in which your production network is down or severely degraded Cisco engineers are assigned immediately to S1 and S2 service requests to help keep your business operations running smoothly To open a service request by telephone use one of the following numbers Asia Pacific 61 2 8446 7411 Australia 1 800 805 227 EMEA 32 2 704 55 55 USA 1 800 553 2447 For a complete list of Cisco TAC contacts go to this URL http www cisco com techsupport contacts Definitions of Service Request Severity To ensure that all service requests are reported in a standard format Cisco has established severity definitions Severity 1 S1 Your network is down or there is a critical impact to your business operations You and Cisco will commit all necessary resources around the clock to resolve the situation Severity 2 S2 Operation of an existing network is severely degraded or significant aspects of your business operation are negatively affected by inadequate performance of Cisco products You and Cisco will commit full time resources during normal business hours to resolve the situation Severity 3 S3 Operational perfor
186. d the or operator combines that result with the MED test med eq 10 or not destination in 10 1 3 0 24 and community matches any 12 34 56 78 Implementing Routing Policy on Cisco IOS XR Software apply Attach Points Information About Implementing Routing Policy i With a set of parentheses to express the precedence the result is the following med eq 10 or not destination in 10 1 3 0 24 and community matches any L2 34 156 78 The following is another example of a complex expression origin is igp or origin is incomplete or not med eq 42 and next hop in 10 0 2 2 The left conjunction is a compound condition enclosed in parentheses The first simple condition of the inner compound condition tests the value of the origin attribute if it is Interior Gateway Protocol IGP then the inner compound condition is true Otherwise the evaluation moves on to test the value of the origin attribute again and if it is incomplete then the inner compound condition is true Otherwise the evaluation moves to check the next component condition which is a negation of a simple condition As discussed in the sections on policy definitions and parameterization of policies the apply command executes another policy either parameterized or unparameterized from within another policy which allows for the reuse of common blocks of policy When combined with the ability to parameterize common blocks of policy the apply co
187. d until the reuse limit is reached upon which the route is once again advertised At half of the reuse limit the dampening information for the route to network A is removed BGP Routing Domain Confederation One way to reduce the iBGP mesh is to divide an autonomous system into multiple subautonomous systems and group them into a single confederation To the outside world the confederation looks like a single autonomous system Each autonomous system is fully meshed within itself and has a few connections to other autonomous systems in the same confederation Although the peers in different autonomous systems have eBGP sessions they exchange routing information as if they were iBGP peers Specifically the next hop MED and local preference information is preserved This feature allows the you to retain a single IGP for all of the autonomous systems BGP Route Reflectors BGP requires that all iBGP speakers be fully meshed However this requirement does not scale well when there are many iBGP speakers Instead of configuring a confederation another way to reduce the iBGP mesh is to configure a route reflector Figure 3 illustrates a simple iBGP configuration with three iBGP speakers routers A B and C Without route reflectors when Router A receives a route from an external neighbor it must advertise it to both routers B and C Routers B and C do not readvertise the iBGP learned route to other iBGP speakers because the routers do not pass
188. des a dynamic mechanism to slow down LSA updates in OSPF during network instability LSA throttling also allows faster OSPF convergence by providing LSA rate limiting in milliseconds Route redistribution Routes learned using any IP routing protocol can be redistributed into any other IP routing protocol Authentication Plain text and MD5 authentication among neighboring routers within an area is supported Routing interface parameters Configurable parameters supported include interface output cost retransmission interval interface transmit delay router priority router dead and hello intervals and authentication key Virtual links Virtual links are supported Not so stubby area NSSA RFC 1587 is supported OSPF over demand circuit RFC 1793 is supported Cisco 10S XR Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software Information About Implementing OSPF on Cisco 10S XR Software W Comparison of Cisco 10S XR OSPFv3 and OSPFv2 Much of the OSPFv3 protocol is the same as in OSPFv2 OSPFV3 is described in RFC 2740 The key differences between the Cisco IOS XR OSPFv3 and OSPF v2 protocols are as follows e OSPFv3 expands on OSPFV2 to provide support for IPv6 routing prefixes and the larger size of IPv6 addresses e When using an NBMA interface in OSPFv3 users must manually configure the router with the list of neighbors Neighboring routers are identified by the link local address of the at
189. directly in a policy rather than having to refer to a named set Prefix lists community lists and AS path lists must be maintained even when only one or two items are in the list An inline set in RPL allows the user to place small sets of values directly in the policy body without having to refer to a named set Decision making such as accept and deny is explicitly controlled by the policy definitions themselves RPL combines matching operators which may use set data with the traditional Boolean logic operators and or and not into complex conditional expressions All matching operations return a true or false result The execution of these conditional expressions and their associated actions can then be controlled by using simple if then elseif and else structures which allow the evaluation paths through the policy to be fully specified by the user Routing Policy Language Structure Names Sets This section describes the basic structure of RPL The policy language provides two kinds of persistent namable objects sets and policies Definition of these objects is bracketed by beginning and ending command lines For example to define a policy named test the configuration syntax would look similar to the following route policy test policy statements end policy Legal names for policy objects can be any sequence of the upper and lowercase alphabetic characters the numerals 0 to 9 and the punctuation characters
190. display the session groups neighbor groups and address family groups from which this neighbor is capable of inheriting configuration The show bgp neighbors command examples that follow are based on the sample configuration RP 0 RPO CPU0 router config router bgp 140 RP 0 RPO CPU0 router config bgp af group GROUP_3 address family ipv4 unicast RP 0 RPO CPU0 router config bgp afgrp next hop self RP 0 RPO CPU0 router config bgp afgrp route policy POLICY_1 in RP 0 RPO CPU0 router config bgp0afgrp exit RP 0 RPO CPU0 router config bgp session group GROUP_2 RP 0 RPO CPUO router config bgp sngrp advertisement interval 15 RP 0 RPO CPU0 router config bgp sngrp exit RP 0 RPO CPU0 router config bgp neighbor group GROUP_1 RP 0 RPO CPU0 router config bgp nbrgrp use session group GROUP_2 RP 0 RPO CPUO router config bgp nbrgrp ebgp multihop 3 RP 0 RPO CPU0 router config bgp nbrgrp address family ipv4 unicast RP 0 RPO CPU0 router config bgp nbrgrp af weight 100 RP 0 RPO CPU0 router config bgp nbrgrp af send community ebgp RP 0 RPO CPU0 router config bgp nbrgrp af exit RP 0 RPO CPU0 router config bgp nbrgrp address family ipv4 multicast RP 0 RPO CPU0 router config bgp nbrgrp af default originate RP 0 RPO CPU0 router config bgp nbrgrp af exit RP 0 RPO CPU0 router config bgp nbrgrp exit RP 0 RPO CPU0 router config bgp neighbor 192 168 0 1 RP 0 RPO CPU0 router config bgp nbr remot
191. do not understand the concept of route reflectors They can be members of either client or nonclient groups allowing an easy and gradual migration from the old BGP model to the route reflector model Initially you could create a single cluster with a route reflector and a few clients All other iBGP speakers could be nonclient peers to the route reflector and then more clusters could be created gradually An autonomous system can have multiple route reflectors A route reflector treats other route reflectors just like other iBGP speakers A route reflector can be configured to have other route reflectors in a client group or nonclient group In a simple configuration the backbone could be divided into many clusters Each route reflector would be configured with other route reflectors as nonclient peers thus all route reflectors are fully meshed The clients are configured to maintain iBGP sessions with only the route reflector in their cluster Usually a cluster of clients has a single route reflector In that case the cluster is identified by the router ID of the route reflector To increase redundancy and avoid a single point of failure a cluster might have more than one route reflector In this case all route reflectors in the cluster must be configured with the Cisco IOS XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software How to Implement BGP on Cisco IOS XR Software W cluster ID so that a route reflect
192. do not have a user ID or password you can register at this URL http tools cisco com RPF register register do Note Use the Cisco Product Identification CPI tool to locate your product serial number before submitting a web or phone request for service You can access the CPI tool from the Cisco Technical Support amp Documentation website by clicking the Tools amp Resources link under Documentation amp Tools Choose Cisco Product Identification Tool from the Alphabetical Index drop down list or click the Cisco Product Identification Tool link under Alerts amp RMAs The CPI tool offers three search options by product ID or model name by tree view or for certain products by copying and pasting show command output Search results show an illustration of your product with the serial number label location highlighted Locate the serial number label on your product and record the information before placing a service call Cisco 10S XR Routing Configuration Guide Preface Obtaining Additional Publications and Information W Submitting a Service Request Using the online TAC Service Request Tool is the fastest way to open S3 and S4 service requests S3 and S4 service requests are those in which your network is minimally impaired or for which you require product information After you describe your situation the TAC Service Request Tool provides recommended solutions If your issue is not resolved using the recommende
193. e or Automatically configures an IPv6 link local address on the interface while also enabling the interface for IPv6 processing e The link local address can be used to communicate only with nodes on the same link e Specifying the ipv6 address ipv6 prefix prefix length interface configuration command without the eui 64 keyword configures site local and global IPv6 addresses e Specifying the ipv6 address ipv6 prefix prefix length command with the eui 64 keyword configures site local and global IPv6 addresses with an interface ID in the low order 64 bits of the IPv6 address Only the 64 bit network prefix for the address needs to be specified the last 64 bits are automatically computed from the interface ID e Specifying the ipv6 address command with the link local keyword configures a link local address on the interface that is used instead of the link local address that is automatically configured when IPv6 is enabled on the interface Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Command or Action Purpose exit Example RP 0 RPO CPU0 router config if exit Exits interface configuration mode and returns the router to global configuration mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enab
194. e RP 0 RPO CPU0 router config bgp af end or RP 0 RPO CPU0 router config bgp af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software How to Implement BGP on Cisco IOS XR Software W Configuring a BGP Neighbor Group Perform this task to configure BGP neighbor groups and apply the neighbor group configuration to a neighbor After a neighbor group is configured each neighbor can inherit the configuration through the use command If a neighbor is configured to use a neighbor group the neighbor by default inherits the entire configuration of the neighbor group which includes the address family independent and address family dependent
195. e page RC 90 Cisco 10S XR Routing Configuration Guide RC 84 l _ Implementing IS IS on Cisco 10S XR Software Information About Implementing IS IS on Cisco 10S XR Software Hi IS IS Functional Overview Small IS IS networks are typically built as a single area that includes all routers in the network As the network grows larger it may be reorganized into a backbone area made up of the connected set of all Level 2 routers from all areas which is in turn connected to local areas Within a local area routers know how to reach all system IDs Between areas routers know how to reach the backbone and the backbone routers know how to reach other areas The IS IS routing protocol supports the configuration of backbone Level 2 and Level areas and the necessary support for moving routing information between the areas Routers establish Level 1 adjacencies to perform routing within a local area intra area routing Routers establish Level 2 adjacencies to perform routing between Level areas interarea routing For Cisco IOS XR software each IS IS instance can support either a single Level or Level 2 area or one of each By default all IS IS instances automatically support Level 1 and Level 2 routing You can change the level of routing to be performed by a particular routing instance using the is type command Key Features Supported in the Cisco IOS XR IS IS Implementation The Cisco IOS XR implementation of IS IS conforms to the
196. e as 2 RP 0 RPO CPU0 router config bgp nbr use neighbor group GROUP_1 RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast RP 0 RPO CPUO router config bgp nbr af use af group GROUP_3 RP 0 RPO CPU0 router config bgp nbr af weight 200 Cisco 10S XR Routing Configuration Guide EE Implementing BGP on Cisco IOS XR Software show bgp af group Information About Implementing BGP on Cisco 10S XR Software The following example displays sample output from the show bgp neighbors command using the inheritance keyword The example shows that the neighbor inherits session parameters from neighbor group GROUP_1 which in turn inherits from session group GROUP_2 The neighbor inherits IPv4 unicast parameters from address family group GROUP_3 and IPv4 multicast parameters from neighbor group GROUP_1 RP 0 RPO CPU0 router show bgp neighbors 192 168 0 1 inheritance Session IPv4 Unicast IPv4 Multicast n GROUP_1 s GROUP_2 a GROUP_3 n GROUP_1 The following example displays sample output from the show bgp neighbors command using the configuration keyword The example shows from where each item of configuration was inherited or if it was configured directly on the neighbor indicated by For example the ebgp multihop 3 command was inherited from neighbor group GROUP_1 and the next hop self command was inherited from the address family group GROUP_3 RP 0 RPO CPU0 router show bgp neighbors 192 16
197. e bgp confederation peers command marks the peers from autonomous systems 6002 and 6003 as special eBGP peers Hence peers 171 69 232 55 and 171 69 232 56 get the local preference next hop and MED unmodified in the updates The router at 160 69 69 1 is a normal eBGP speaker and the updates received by it from this peer are just like a normal eBGP update from a peer in autonomous system 666 router bgp 6001 bgp confederation identifier 666 bgp confederation peers 6002 6003 neighbor 171 69 232 55 remote as 6002 neighbor 171 69 232 56 remote as 6003 neighbor 160 69 69 1 remote as 777 In a BGP speaker in autonomous system 6002 the peers from autonomous systems 6001 and 6003 are configured as special eBGP peers Peer 170 70 70 1 is a normal iBGP peer and peer 199 99 99 2 is a normal eBGP peer from autonomous system 700 router bgp 6002 bgp confederation identifier 666 bgp confederation peers 6001 6003 neighbor 170 70 70 1 remote as 6002 neighbor 171 69 232 57 remote as 6001 neighbor 171 69 232 56 remote as 6003 Cisco IOS XR Routing Configuration Guide RC 78 _ mplementing BGP on Cisco 10S XR Software Where to Go Next W neighbor 199 99 99 2 remote as 700 In a BGP speaker in autonomous system 6003 the peers from autonomous systems 6001 and 6002 are configured as special eBGP peers Peer 200 200 200 200 is a normal eBGP peer from autonomous system 701 router bgp 6003 bgp confederation identifier 666 bgp
198. e exit command as an alternative to the endif command The if statement also permits an else clause which is executed if the if condition is false if med eq 8 then set community 12 34 additive else set community 12 56 additive endif The policy language also provides syntax using the elseif keyword to string together a sequence of tests if med eq 150 then set local preference 10 elseif med eq 200 then set local preference 60 elseif med eq 250 then set local preference 110 else set local preference 0 endif Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy The statements within an if statement may themselves be if statements as shown in the following example if community matches any 12 34 56 78 then if med eq 150 then drop endif set local preference 100 endif This policy example sets the value of the local preference attribute to 100 on any route that has a community value of 12 34 or 56 78 associated with it However if any of these routes has a MED value of 150 then these routes with either the community value of 12 34 or 56 78 and a MED of 150 are dropped Boolean Conditions Cisco IOS XR Routing Configuration Guide In the previous section describing the if statement all of the examples use simple Boolean conditions that evaluate to either true or false RPL also provides a way to build compound c
199. e forwarding IP packets and perform a graceful restart following an RP failover When a router restarts all routing peers of that device usually detect that the device went down and then came back up This transition results in what is called a routing flap which could spread across multiple routing domains Routing flaps caused by routing restarts create routing instabilities which are detrimental to the overall network performance NSF helps to suppress routing flaps in NSF aware devices thus reducing network instability NSF allows for the forwarding of data packets to continue along known routes while the routing protocol information is being restored following an RP failover When the NSF feature is configured peer networking devices do not experience routing flaps Data traffic is forwarded through intelligent line cards or dual forwarding processors FPs while the standby RP assumes control from the failed active RP during a failover The ability of line cards and FPs to remain up through a failover and to be kept current with the Forwarding Information Base FIB on the active RP is key to NSF operation When the Cisco IOS XR router running IS IS routing performs an RP failover the router must perform two tasks to resynchronize its link state database with its IS IS neighbors First it must relearn the available IS IS neighbors on the network without causing a reset of the neighbor relationship Second it must reacquire the contents of t
200. e parameterized Every extended community set must contain at least one extended community value Empty extended community sets are invalid and rejected A prefix set holds IPv4 or IPv6 prefix match specifications each of which has four parts an address a mask length a minimum matching length and a maximum matching length The address is required but the other three parts are optional The address is a standard dotted decimal IPv4 or colon separated hexadecimal IPv6 address The mask length if present is a nonnegative decimal integer in the range from 0 to 32 0 to 128 for IPv6 following the address and separated from it by a slash The optional minimum matching length follows the address and optional mask length and is expressed as the keyword ge mnemonic for greater than or equal to followed by a nonnegative decimal integer in the range from 0 to 32 0 to 128 for IPv6 The optional maximum matching length follows the rest and is expressed by the keyword le mnemonic for less than or equal to followed by yet another nonnegative decimal integer in the range from 0 to 32 0 to 128 for IPv6 A syntactic shortcut for specifying an exact length for prefixes to match is the eq keyword mnemonic for equal to If a prefix match specification has no mask length then the default mask length is 32 for IPv4 and 128 for IPv6 The default minimum matching length is the mask length If a minimum matching length is specified then the default maximum
201. e password is used in HMAC MD5 authentication The text keyword specifies that the password uses cleartext password authentication The clear keyword specifies that the password is unencrypted when entered The encrypted keyword specifies that the password is encrypted using a two way algorithm when entered The level 1 keyword sets a password for authentication in the area in Level 1 LSPs and Level SNPs The level 2 keywords set a password for authentication in the backbone the Level 2 area The send only keyword adds authentication to LSP and sequence number protocol data units SNPs when they are sent It does not authenticate received LSPs or SNPs The snp send only keyword adds authentication to SNPs when they are sent It does not authenticate received SNPs To disable SNP password checking the snp send only keywords must be specified in the Isp password command interface type instance Example RP 0 RPO CPU0 router config isis interface POS 0 1 0 3 Enters interface configuration mode Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Command or Action Purpose Step5 hello password hmac md5 text clear Configures the authentication password for an IS IS encrypted password level 1 2 send only interface Example RP 0 RPO CPU1 router config isis if hello password text c
202. e provider ISP router to install a route with a local next hop for that address that drops all traffic destined for it BGP Configuration Cisco IOS XR BGP follows a neighbor based configuration model that requires that all configurations for a particular neighbor be grouped in one place under the neighbor configuration Peer groups are not supported for either sharing configuration between neighbors or for sharing update messages The concept of peer group has been replaced by a set of configuration groups to be used as templates in BGP configuration and automatically generated update groups to share update messages between neighbors BGP configurations are grouped into four major categories Router Configuration Mode Global Address Family Configuration Mode Neighbor Configuration Mode Neighbor Address Family Configuration Mode Configuration Modes The following sections show how to enter each of the configuration modes From a mode you can enter the command to display the commands available in that mode Cisco 10S XR Routing Configuration Guide RC 4 _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W Router Configuration Mode The following example shows how to enter router configuration mode RP O0 RPO CPU0 router configuration RP 0 RPO CPU0 router config router bgp 140 RP 0 RPO CPU0 router config bgp Global Address Family Configuration
203. e used for discarding traffic to a particular prefix For example if it is required to discard all traffic to prefix 2001 0DB8 42 1 64 the following static route would be defined configure route ipv6 unicast 2001 0DB8 42 1 64 null 0 end Configuring a Fixed Default Route Example A default static route is often used in simple router topologies In the following example a router is configured with an administrative distance of 110 configure route ipv4 unicast 10 0 0 0 8 172 20 16 6 110 end Configuring a Floating Static Route Example A floating static route often is used to provide a backup path if connectivity fails In the following example a router is configured with an administrative distance of 201 configure route ipv6 unicast 2001 0DB8 32 2001 0DB8 3000 1 201 end Where to Go Next For additional information on static routes routing protocols and RIB consult the following publications e Implementing and Monitoring RIB on Cisco IOS XR Software e Implementing BGP on Cisco IOS XR Software e Implementing IS IS on Cisco IOS XR Software e Implementing OSPF on Cisco IOS XR Software e Implementing OSPF v3 on Cisco IOS XR Software e RIB Commands on Cisco IOS XR Software Cisco 10S XR Routing Configuration Guide JL RC 255_ Implementing Static Routes on Cisco 10S XR Software W Additional References Additional References The following sections provide references related to implementing static rou
204. egorized as severity Level 5 in the logging console command The logging console command controls which severity level of messages are sent to the console By default all severity level messages are sent end or commit Example RP 0 RPO CPU0 router config ospf ar if end or RP 0 RPO CPU0 router config ospf ar if commit Saves configuration changes When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuring Stub and Not so Stubby Area Types This task explains how to configure the stub area and the NSSA for OSPF SUMMARY STEPS 1 configure 2 router ospf process name or router ospfv3 process name 3 router id ipv4 address interface type interface instance 4 area area id 5 stub no summary or nssa no redistribution default inf
205. elf is partitioned Cisco IOS XR Routing Configuration Guide RC 138 _ mplementing OSPF on Cisco 10S XR Software Information About Implementing OSPF on Cisco 10S XR Software W In the case in which an area cannot be connected to Area 0 you must configure a virtual link between that area and Area 0 The two endpoints of a virtual link are ABRs and the virtual link must be configured in both routers The common nonbackbone area to which the two routers belong is called a transit area A virtual link specifies the transit area and the router ID of the other virtual endpoint the other ABR A virtual link cannot be configured through a stub area or NSSA Figure 7 illustrates a virtual link from Area 3 to Area 0 Figure 7 Virtual Link to Area 0 OSPF Domain BGP autonomous system 109 K Area 0 b Backbone Area 3 N Transit Area Ji C BEP Router ID 5 5 5 5 Router ID 4 4 4 4 ASBR 2 88722 Route Redistribution for OSPF Redistribution allows different routing protocols to exchange routing information This technique can be used to allow connectivity to span multiple routing protocols It is important to remember that the redistribute command controls redistribution into an OSPF process and not from OSPF See the Configuration Examples for Implementing OSPF on Cisco IOS XR Software section on page RC 1
206. ement For example the following policy drops all routes because it neither modifies the attribute of any route nor explicitly passes it route policy EMPTY end policy Whereas the following policies pass all routes that they evaluate route policy PASS ALL pass end policy route policy SET LPREF set local preference 200 end policy In addition to being implicitly dropped a route may be dropped by an explicit drop statement Drop statements cause a route to be dropped immediately so that no further policy processing is done Note also that a drop statement overrides any previously processed pass statements or attribute modifications For example the following policy drops all routes The first pass statement is executed but is then immediately overridden by the drop statement The second pass statement never gets executed route policy DROP EXAMPLE pass drop pass end policy When one policy applies another it is as if the applied policy were copied into the right place in the applying policy and then the same drop and pass semantics are put into effect For example policies ONE and TWO are equivalent to policy ONE PRIME route policy ONE apply route policy two if as path neighbor is 123 then pass endif end policy route policy TWO if destination in 10 0 0 0 16 le 32 then drop endif end policy route policy ONE PRIME if destination in 10 0 0 0 16 le 32 then drop endif if as path neighbor is 1
207. er poll interval seconds cost number database filter all or neighbor ipv6 link local address priority number poll interval seconds cost number database filter all 14 Repeat Step 13 for all neighbors on the interface 15 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RPO CPU0 router configure Step2 router ospf process name Enables OSPF routing for the specified routing process and or places the router in router configuration mode router ospfv3 process name or Enables OSPFv3 routing for the specified routing process Example and places the router in router ospfv3 configuration mode RP 0 RPO CPU0 router config router ospf 1 or Note The process name argument is any alphanumeric string no longer than 40 characters RP 0 RP0 CPU0 router config router ospfv3 1 Ste p3 router id ipv4 address interface type Configures a router ID for the OSPF process interface instance i Note We recommend using a stable IP address as the router ID Example RP 0 RP0 CPU0 router config ospf router id 192 168 4 3 Step4 area area id Enters area configuration mode and configures an area for the OSPF process Example e This example configures a backbone area RP 0 RP0 CPU0 router config ospf area 0 R 7 SSpS e The area id argument can be entered in dotted decimal or IPv4 address notation such as area 1000 or area 0 0 3
208. er routes 7 show bgp paths Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software 8 show bgp neighbor group group name configuration 9 show bgp summary DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Command or Action Purpose show bgp cidr only Example RP 0 RPO CPU0 router show bgp cidr only Displays routes with nonnatural network masks classless interdomain routing CIDR routes show bgp count only Example RP 0 RPO CPU0 router show bgp count only Displays the number of paths show bgp community community list exact match Example RP 0 RPO CPU0 router show bgp community 1081 5 exact match Displays routes that match the BGP community 1081 5 show bgp regexp regular expression Example RP 0 RPO CPU0 router show bgp regexp 3 Displays routes that match the autonomous system path regular expression 43 show bgp Example RP 0 RPO CPU0 router show bgp Displays entries in the BGP routing table show bgp neighbors ip address advertised routes dampened routes flap statistics performance statistics received prefix filter routes Example RP 0 RPO CPU0 router show bgp neighbors 10 0 101 1 Displays information about the BGP connection to neighbor 10 0 101 1 e The advertised routes keyword displays all routes the router adv
209. er ospf configuration levels For example the hello interval value for an interface is determined by this precedence IF statement If the hello interval command is configured at the interface configuration level then use the interface configured value else If the hello interval command is configured at the area configuration level then use the area configured value else If the hello interval command is configured at the router ospf configuration level then use the router ospf configured value else Use the default value of the command Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HI Information About Implementing OSPF on Cisco 10S XR Software p Tip Understanding hierarchical CLI and CLI inheritance saves you considerable configuration time See the Configuring Authentication at Different Hierarchical Levels for OSPF Version 2 section on page RC 155 to understand how to implement these fundamentals In addition Cisco IOS XR examples are provided in the Configuration Examples for Implementing OSPF on Cisco IOS XR Software section on page RC 187 OSPF Routing Components Before implementing OSPF you must know what the routing components are and what purpose they serve They consist of the autonomous system area types interior routers ABRs and ASBRs Figure 6 illustrates the routing components in an OSPF network topology Figure 6 OSPF Routing Comp
210. erface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IP address as the router ID area area id Example RP 0 RPO CPU0 router config ospf area 0 Enters area configuration mode and configures an area for the OSPF process e Backbone areas have an area ID of 0 e Nonbackbone areas have a nonzero area ID e The area id argument can be entered in dotted decimal or IPv4 address notation such as area 1000 or area 0 0 3 232 However you must choose one form or the other for an area We recommend using the IPv4 address notation interface type instance Example RP 0 RPO CPU0 router config ospf ar interface POS 0 1 0 3 Enters interface configuration mode and associates one or more interfaces for the area configured in Step 4 Repeat Step 5 for each interface that uses OSPF Cisco 10S XR Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software Step 7 Step 8 How to Implement OSPF on Cisco 10S XR Software W Command or Action Purpose log adjacency changes detail disable enable Example RP 0 RPO CPU0 router config ospf ar if log adjacency changes detail Optional Requests notification of neighbor changes By default this feature is enabled The messages generated by neighbor changes are considered notifications which are cat
211. ers global address family configuration mode for the IPv4 address family Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Command or Action Purpose Step 4 aggregate address address mask length as set as confed set summary only route policy route policy name Example RP 0 RPO CPU0 router config bgp af aggregate address 10 0 0 0 8 as set Creates an aggregate address The path advertised for this route is an autonomous system set consisting of all elements contained in all paths that are being summarized e The as set keyword generates autonomous system set path information and community information from contributing paths e The as confed set keyword generates autonomous system confederation set path information from contributing paths e The summary only keyword filters all more specific routes from updates e The route policy route policy name keyword and argument specify the route policy used to set the attributes of the aggregate route Step5 end or commit Example RP 0 RPO CPU0 router config bgp af end or RP 0 RPO CPU0 router config bgp af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration ch
212. ertised to the neighbor e The dampened routes keyword displays the dampened routes that are learned from the neighbor e The flap statistics keyword displays flap statistics of the routes learned from the neighbor e The performance statistics keyword displays performance statistics relating to work done by the BGP process for this neighbor e The received prefix filter keyword and argument display the received prefix list filter e The routes keyword displays routes learned from the neighbor Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Step 7 Step 8 Step 9 Command or Action How to Implement BGP on Cisco IOS XR Software W Purpose show bgp paths Example RP 0 RPO CPU0 router show bgp paths Displays all BGP paths in the database show bgp neighbor group group name configuration Example RP 0 RPO CPU0 router show bgp neighbor group group_1 configuration Displays the effective configuration for neighbor group group_1 including any configuration inherited by this neighbor group show bgp summary Example RP O0 RPO CPU0 router show bgp summary Displays the status of all BGP connections Monitoring BGP Update Groups This task displays information related to the processing of BGP update groups SUMMARY STEPS 1 show bgp ipv4 ipv6 all unicast multicast all update group neighbor ip address process id index
213. erval between the same OSPF LSAs that the router originates e The default is 5 seconds for both OSPF and OSPFv3 timers lsa min arrival seconds Example RP 0 RPO CPU0 router config ospf timers lsa min arrival 2 Limits the frequency that new processes of any particular OSPF Version 2 LSA can be accepted during flooding e The default is 1 second Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software Step 7 Step 8 Command or Action Purpose timers lsa group pacing seconds Example RP 0 RPO CPU0 router config ospf timers lsa group pacing 1000 Changes the interval at which OSPF link state LSAs are collected into a group for flooding The default is 240 seconds end or commit Example RP 0 RPO CPU0 router config ospf end or RP 0 RPO CPU0 router config ospf commit Saves configuration changes When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current c
214. erwise the default value is used In the example that follows neighbor 10 0 101 5 has the minimum time between advertisement runs set to 30 seconds default because the neighbor is not configured to use the neighbor configuration or the neighbor group configuration RP 0 RPO CPU0O router config router bgp 140 RP 0 RPO CPU0 router config bgp neighbor group AS_1 RP 0 RPO CPU0 router config bgp nbrgrp remote as 1 RP 0 RPO CPU0 router config bgp nbrgrp exit RP 0 RPO CPU0 router config bgp nbrgrp neighbor group adv_15 RP 0 RPO CPU0 router config bgp nbrgrp remote as 10 RP 0 RPO CPU0 router config bgp nbrgrp advertisement interval 15 RP 0 RPO CPU0 router config bgp nbrgrp exit RP 0 RPO CPU0 router config bgp neighbor 10 0 101 5 RP 0 RPO CPU0 router config bgp nbr use neighbor group AS_1 RP 0 RPO CPU0 router config bgp nbr exit RP 0 RPO CPU0 router config bgp neighbor 10 0 101 10 RP 0 RPO CPU0 router config bgp nbr use neighbor group adv_15 The following output from the show bgp neighbors command shows that the advertisement interval used is 30 seconds RP O0 RPO CPU0 router show bgp neighbors 10 0 101 5 BGP neighbor is 10 0 101 5 remote AS 1 local AS 140 external link Remote router ID 0 0 0 0 BGP state Idle Last read 00 00 00 hold time is 180 keepalive interval is 60 seconds Received 0 messages 0 notifications 0 in queue Sent 0 messages 0 notifications 0 in queue M
215. es how to enable multicast intact for IS IS routes that use IPv4 addresses Summary Steps 1 configure router isis instance id mpls traffic eng multicast intact oF N end or commit address family ipv4 ipv6 unicast Cisco IOS XR Routing Configuration Guide _ Implementing IS IS on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 How to Implement IS IS on Cisco IOS XR Software Hi Command or Action Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enables IS IS routing for the specified routing process and places the router in router configuration mode In this example the IS IS instance is called isp address family ipv4 ipv6 unicast Example RP 0 RPO CPU0 router config isis address family ipv4 Specifies the IPv4 or IPv6 address family and enters router address family configuration mode This example specifies the unicast IPv4 address family mpls traffic eng multicast intact Example RP 0 RPO CPU0 router config isis mpls traffic eng multicast intact Enables multicast intact end or commit Example RP 0 RPO CPU0 router config isis af end or RP 0 RPO CPU0 router config isis af commit Saves configuration changes e When you issue the end command the system
216. ess prefix length link local or ipv6 enable exit router isis instance id net network entity title address family ipv6 unicast single topology sa ss SS oO UF exit 10 interface type instance 11 circuit type level 1 level 1 2 level 2 only 12 address family ipv4 ipv6 unicast 13 end or commit 14 show isis instance instance id interface type instance detail level 1 2 15 show isis instance instance id topology systemid system id level 1 2 summary Cisco 10S XR Routing Configuration Guide RC 94 _ Implementing IS IS on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Command or Action How to Implement IS IS on Cisco IOS XR Software Hi Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode interface type number Example RP 0 RPO CPU0 router config interface POS 0 1 0 3 Enters interface configuration mode ipv4 address address mask or ipv6 address ipv6 prefix prefix length eui 64 or ipv6 address ipv6 address prefix length link local or ipv6 enable Example RP 0 RPO CPU0 router config if ipv4 address 10 0 1 3 255 255 255 0 or RP 0 RPO CPU0O router config if ipv6 address 3f fe 1234 c18 1 64 eui 64 or RP 0 RPO CPU0 router config if ipv6 address FE80 260 3EFF FE11 6770 link local or RP 0 RPO CPU0O router con
217. ess prefix length level 1 2 re lipv6 prefix prefix length level 11 2 8 maximum paths route number 9 distance weight address prefix length route list name 10 set attached bit 11 end or commit DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Command or Action Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enables IS IS routing for the specified routing process and places the router in router configuration mode e By default all IS IS instances are automatically Level 1 and Level 2 You can change the level of routing to be performed by a particular routing instance using the is type command set overload bit on startup delay wait for bgp level 1 2 Example RP 0 RPO CPU0 router config isis set overload bit Optional Sets the overload bit Note The configured overload bit behavior does not apply to NSF restarts because the NSF restart does not set the overload bit during restart address family ipv4 ipv6 unicast Example RP 0 RPO CPU0 router config isis address family ipv6 unicast Specifies the IPv4 or IPv6 address family and enters router address family configuration mode e This example specifies the unicast IPv6 address family Cisco 10S XR Routing Configuration Guide _ Implementing IS IS on C
218. evices be NSF aware which happens automatically after you install the Cisco IOS XR image on the router If an NSF capable router discovers that it has non NSF aware neighbors on a particular network segment it disables NSF capabilities for that segment Other network segments composed entirely of NSF capable or NSF aware routers continue to provide NSF capabilities See the Nonstop Forwarding for OSPF Version 2 section on page RC 140 for conceptual information Restrictions The following are restrictions when configuring nonstop forwarding e OSPF Cisco NSF for virtual links is not supported e Neighbors must be NSF aware SUMMARY STEPS 1 configure router ospf process name router id ipv4 address interface type interface instance e N nsf or nsf enforce global 5 nsf interval seconds 6 end or commit Cisco 10S XR Routing Configuration Guide JL RC 173_ Implementing OSPF on Cisco IOS XR Software HT How to Implement OSPF on Cisco IOS XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Command or Action Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router ospf process name Example RP 0 RPO CPU0 router config router ospf 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode Note The process name argument is any alphanumeric string no longer than 40 char
219. exiting yes no cancel RP 0 RP0 CPU0 router config bgp nbr end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP 0 RPO CPU0 router config bgp nbr commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuring a BGP Neighbor Perform this task to configure BGP neighbors SUMMARY STEPS 1 configure router bgp autonomous system number neighbor ip address remote as autonomous system number address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast D9 ao FF wN end or commit Cisco IOS XR Routing Configuration Guide RC 58 _ mplementing BGP on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 How to Implement BGP on Cisco IOS XR Software Hi Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 12
220. f the virtual link You do not want them to be subject to change which could happen if they are assigned by default See the OSPF Process and Router ID section on page RC 134 for an explanation of how the router ID is determined Therefore we recommend that you perform one of the following tasks before configuring a virtual link Use the router id command to set the router ID This strategy is preferable Configure a loopback interface so that the router has a stable router ID Before configuring your virtual link for OSPF Version 2 you must decide whether to configure plain text authentication MD5 authentication or no authentication which is the default Your decision determines whether you need to perform additional tasks related to authentication Note If you decide to configure plain text authentication or no authentication see the authentication command provided in the OSPF Commands on Cisco IOS XR Software module in the Cisco IOS XR Routing Command Reference SUMMARY STEPS o oo Nn FF FS 11 show ospf process name or show ospfv3 process name configure router ospf process name or router ospfv3 process name router id ipv4 address interface type interface instance area area id virtual link router id authentication message digest message digest key key id md5 key clear key encrypted key Repeat all of the steps in this task on the ABR that is at the other end of the virtual link Spec
221. face that must communicate using the same authentication 11 authentication message digest null 12 interface type instance 13 Repeat Step 7 for each interface that must communicate using the same authentication 14 interface type instance 15 authentication message digest null 16 end or commit DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Command or Action Purpose configure Example RP 0 RP0 CPU0 router configure Enters global configuration mode router ospf process name Example RP 0 RP0 CPU0 router config router ospf 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode Note The process name argument is any alphanumeric string no longer than 40 characters router id ipv4 address interface type interface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process authentication message digest null Example RP 0 RPO CPU0 router config ospf authentication message digest Enables MD5 authentication for the OSPF process e This authentication type applies to the entire router process unless overridden by a lower hierarchical level such as the area or interface message digest key key id md5 key clear key enerypted key Example RP 0 RPO CPU0 router config ospf message digest key 4 md5 yourkey
222. fi all Displays more detailed route information on the specified ipv4 ipv6 unicast multicast safi all routing table ip address mask e This command is usually issued with an IP address or other optional filters to limit its display Otherwise it displays all routes from the default IPv4 unicast routing table which can result in an extensive list depending on the configuration of the network Example RP O0 RPO CPU0 router show route ipv4 unicast Verifying Networking and Routing Problems This task verifies the operation of the routes between nodes SUMMARY STEPS 1 show route protocol instance afi all ipv4 ipv6 unicast multicast safi all ip address mask 2 show route afi all ipv4 ipv6 unicast multicast safi all backup ip address 3 show route afi all ipv4 ipv6 unicast multicast safi all best local ip address 4 show route afi all ipv4 ipv6 unicast multicast safi all connected Cisco 10S XR Routing Configuration Guide RC 198 l Implementing and Monitoring RIB on Cisco 10S XR Software How to Deploy and Monitor RIB W 5 show route afi all ipv4 ipv6 unicast multicast safi all local interface 6 show route afi all ipv4 ipv6 unicast multicast safi all ip address mask longer prefixes 7 show route afi all ipv4 ipv6 unicast multicast safi all next hop ip address DETAILED STEPS Step 1 Step 2 Step 3
223. fied interval after an IS IS restart to permit the database to stabilize After the startup delay elapses the ISPF is principally responsible for performing all of the SPF calculations The reseed interval enables a periodic running of the full SPF to ensure that the iSFP state remains synchronized 1 configure router isis instance id address family ipv4 ipv6 unicast FPF N spf interval initial wait initial secondary wait secondary maximum wait maximum evel 112 5 ispf startup delay seconds level 1 2 6 ispf startup delay seconds level 1 2 7 end or commit 8 show isis instance instance id spf log level 1 2 ipv4 ipv6 unicast ispf fspf prc detail internal last number first number Cisco 10S XR Routing Configuration Guide RC 116 _ Implementing IS IS on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Command or Action How to Implement IS IS on Cisco IOS XR Software Hi Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enables IS IS routing for the specified routing instance and places the router in router configuration mode e You can change the level of routing to be performed by a particular routing instance using the is type router configuration comman
224. fig if ipv6 enable Defines the IPv4 address for the interface An IP address is required on all interfaces in an area enabled for IS IS if any one interface is configured for IS IS routing or Specifies an IPv6 network assigned to the interface and enables IPv6 processing on the interface with the eui 64 keyword or Specifies an IPv6 address assigned to the interface and enables IPv6 processing on the interface with the link local keyword or Automatically configures an IPv6 link local address on the interface while also enabling the interface for IPv6 processing e The link local address can be used only to communicate with nodes on the same link e Specifying the ipv6 address ipv6 prefix prefix length interface configuration command without the eui 64 keyword configures site local and global IPv6 addresses e Specifying the ipv6 address ipv6 prefix prefix length command with the eui 64 keyword configures site local and global IPv6 addresses with an interface ID in the low order 64 bits of the IPv6 address Only the 64 bit network prefix for the address needs to be specified the last 64 bits are automatically computed from the interface ID e Specifying the ipv6 address command with the link local keyword configures a link local address on the interface that is used instead of the link local address that is automatically configured when IPv6 is enabled on the interface Cisco 10S XR
225. g by Henk Smit and Toni Li Draft ietf isis restart 04 txt Restart Signalling for IS IS by M Shand and Les Ginsberg Draft ietf isis igp p2p over lan 05 txt Point to point operation over LAN in link state routing protocols by Naiming Shen MIBs MIBs MIBs Link There are no applicable MIBs for this module To locate and download MIBs for selected platforms using Cisco IOS XR software use the Cisco MIB Locator found at the following URL http cisco com public sw center netmgmt cmtk mibs shtml Cisco 10S XR Routing Configuration Guide _Implementing IS IS on Cisco 10S XR Software RFCs Additional References W RFCs Title RFC 1142 OSI IS IS Intra domain Routing Protocol RFC 1195 Use of OSI IS IS for Routing in TCP IP and Dual Environments RFC 2763 Dynamic Hostname Exchange Mechanism for IS IS RFC 2966 Domain wide Prefix Distribution with Two Level IS IS RFC 2973 IS IS Mesh Groups RFC 3277 IS IS Transient Blackhole Avoidance RFC 3373 Three Way Handshake for IS IS Point to Point Adjacencies RFC 3567 IS IS Cryptographic Authentication Technical Assistance Description Link The Cisco Technical Support website contains thousands of pages of searchable technical content including links to products technologies solutions technical tips and tools Registered Cisco com users can log in from this page to access even more content http www
226. g ospf commit Saves configuration changes When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuring OSPF Version 2 for MPLS Traffic Engineering This task explains how to configure OSPF for MPLS TE This task is optional For a description of the MPLS TE tasks and commands that allow you to configure the router to support tunnels configure an MPLS tunnel that OSPF can use and troubleshoot MPLS TE see the Implementing MPLS Traffic Engineering Configuration Guide Prerequisites Your network must support the following Cisco IOS XR features before you enable MPLS TE for OSPF on your router e MPLS e IP Cisco Express Forwarding CEF Note portion of your network You must enter the commands in the following task on every OSPF router in the traffic engineered
227. ggregate addresses for OSPF or Optional Creates aggregate addresses for OSPFv3 e This command provides external route summarization of the non OSPF routes e External ranges that are being summarized should be contiguous Summarization of overlapping ranges from two different routers could cause packets to be sent to the wrong destination e This command is optional If you do not specify it each route is included in the link state database and advertised in LSAs e Inthe OSPFv2 example the summary address 10 1 0 0 includes address 10 1 1 0 10 1 2 0 10 1 3 0 and so on Only the address 10 1 0 0 is advertised in an external LSA e Inthe OSPFv3 example the summary address 2010 11 22 32 has addresses such as 2010 11 22 0 1000 1 2010 11 22 0 2000 679 1 and so on Only the address 2010 11 22 32 is advertised in the external LSA Step6 end or commit Example RP 0 RPO CPU0 router config ospf end or RP 0 RPO CPU0 router config ospf commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel1 cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configura
228. gment have a central point of contact for information exchange Instead of each router exchanging routing updates with every other router on the segment each router exchanges information with the DR and BDR The DR and BDR relay the information to the other routers On broadcast network segments the number of OSPF packets is further reduced by the DR and BDR sending such OSPF updates to a multicast IP address that all OSPF routers on the network segment are listening on Cisco 10S XR Routing Configuration Guide RC 136 _Implementing OSPF on Cisco 10S XR Software Information About Implementing OSPF on Cisco 10S XR Software W The software looks at the priority of the routers on the segment to determine which routers are the DR and BDR The router with the highest priority is elected the DR If there is a tie then the router with the higher router ID takes precedence After the DR is elected the BDR is elected the same way A router with a router priority set to zero is ineligible to become the DR or BDR Default Route for OSPF Type 5 ASE LSAs are generated and flooded to all areas except stub areas For the routers in a stub area to be able to route packets to destinations outside the stub area a default route is injected by the ABR attached to the stub area The cost of the default route is 1 default or is determined by the value specified in the default cost command Link State Advertisement Types for OSPF Version 2 Ea
229. gp cost to provide a source value Table 4 summarizes which operations are valid and where they are valid Cisco IOS XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy i Table 4 Restricted BGP Operations by Attach Point import export aggregation redistribution prepend as path eBGP only eBGP only n a n a set med igp cost forbidden eBGP only forbidden forbidden set weight n a forbidden n a n a suppress forbidden forbidden n a forbidden OSPF Policy Attach Points Default Originate Redistribute This section describes each of the OSPF policy attach points and provides a summary of the OSPF attributes and operators The default originate attach point allows the user to conditionally inject the default route 0 0 0 0 0 into the OSPF link state database which is done by evaluating the attached policy If any routes in the local RIB pass the policy then the default route is inserted into the link state database The following example shows how to generate a default route if any of the routes that match 10 0 0 0 8 ge 8 le 25 are present in the RIB route policy ospf originate if rib has route in 10 0 0 0 8 ge 8 le 25 then pass endif end policy router ospf 1 default information originate policy ospf originate The redistribute attach point within OSPF injects routes from other routing protocol sources into the OSPF l
230. h area that is attached to including the backbone area ABRs also send configuration summaries for their attached areas to the backbone area which then distributes this information to other OSPF areas in the autonomous system In Figure 6 there are two ABRs ABR 1 interfaces Area 1 to the backbone area ABR 2 interfaces the backbone Area 0 to Area 2 a stub area Autonomous System Boundary Routers ASBR ASBRs provide connectivity from one autonomous system to another system ASBRs exchange their autonomous system routing information with boundary routers in other autonomous systems Every router inside an autonomous system knows how to reach the boundary routers for its autonomous system ASBRs can import external routing information from other protocols like BGP and redistribute them as AS external ASE Type 5 LSAs to the OSPF network If the Cisco IOS XR router is an ASBR you can configure it to advertise VIP addresses for content as autonomous system external routes In this way ASBRs flood information about external networks to routers within the OSPF network ASBR routes can be advertised as a Type 1 or Type 2 ASE The difference between Type 1 and Type 2 is how the cost is calculated For a Type 2 ASE only the external cost metric is considered when multiple paths to the same destination are compared For a Type 1 ASE the combination of the external cost and cost to reach the ASBR is used Type 2 external cost is the default and is al
231. h nor maximum length is valid without a mask length The maximum length must be at least the mask length For IPv4 the minimum length must be less than 32 the maximum length of an IPv4 prefix For IPv6 the minimum length must be less than 128 the maximum length of an IPv6 prefix The maximum length must be equal to or greater than the minimum length Routing Policy Language Components Four main components in the routing policy language are involved in defining modifying and using policies the configuration front end policy repository execution engine and policy clients themselves The configuration front end CLI is the mechanism to define and modify policies This configuration is then stored on the router using the normal storage means and can be displayed using the normal configuration show commands The second component of the policy infrastructure the policy repository has several responsibilities First it compiles the user entered configuration into a form that the execution engine can understand Second it performs much of the verification of policies and it ensures that defined policies can actually be executed properly Third it tracks which attach points are using which policies so that when policies are modified the appropriate clients are properly updated with the new policies relevant to them The third component is the execution engine This component is the piece that actually runs policies as the clients request The
232. hanism for an atomic change so that if a policy is redeclared or edited using the emacs editor the new configuration is applied immediately which allows for policies that are in use to be changed without having a window of time in which no policy is applied at the given attach point Verification of Attribute Comparisons and Actions The policy repository knows which attributes actions and comparisons are valid at each attach point When a policy is attached these actions and comparisons are verified against the capabilities of that particular attach point Take for example the following policy definition route policy bad set med 100 set level level 1 2 set cost 200 end policy This policy attempts to perform actions to set the BGP attribute med IS IS attribute level and OSPF attribute cost The system allows you to define such a policy but it does not allow you to attach such a policy If you had defined the policy bad and then attempted to attach it as an inbound BGP policy using the BGP configuration statement neighbor 1 2 3 4 address family ipv4 unicast route policy bad in the system would reject this configuration attempt This rejection results from the verification process checking the policy and realizing that while BGP could set the MED it has no way of setting the level or cost as the level and cost are attributes of IS IS and OSPF respectively Instead of silently omitting the actions that cannot be done the system generates
233. has 1 MPLS TE fragment Area instance is 3 MPLS router address is 192 168 4 2 Next fragment ID is 1 Fragment 0 has 1 link Fragment instance is 3 Fragment has 0 link the same as last update Fragment advertise MPLS router address Link is associated with fragment 0 Link ID 55 55 55 55 Interface Address 192 168 50 21 Neighbor Address 192 168 4 1 Admin Metric 0 Maximum bandwidth 19440000 Maximum global pool reservable bandwidth 25000000 Maximum sub pool reservable bandwidth Number of Priority 8 Global pool unreserved BW Priority 0 25000000 Priority 2 25000000 Priority 4 25000000 Priority 6 25000000 Sub pool unreserved BW Priority 0 3125000 Priority 2 3125000 Priority 4 3125000 Priority 6 3125000 Affinity Bit 0 Priority Priority Priority NOwWwp Priority Priority Priority Priority Priority Nowe Link instance is 3 Link connected to Point to Point network 23125000 25000000 25000000 25000000 25000000 3125000 3125000 3125000 3125000 In the following example the show ospf mpls traffic eng EXEC command verifies that the MPLS TE links on area instance 3 are configured correctly RP 0 RPO CPU0 router show ospf mpls traffic eng link OSPF Router with ID Area 0 has 1 MPLS TE links Links in hash bucket 53 192 168 4 1 Process ID 1 Area instance is 3 Link is associated with fragment 0 Link ID 192 168 50 20 Interface Address 192 1
234. he intervals at which the SPF calculations occur as long as at least one topology change event is received in a given wait interval Figure 8 SPF Calculation Intervals Set by the timers spf Command 5ms 2000 ms 8000 ms 32000 ms 90000 ms 1000 ms 4000 ms 16000 ms 64000 ms 88278 Notice that the wait interval between SPF calculations doubles when at least one topology change event is received during the previous wait interval After the maximum wait time is reached the wait interval remains the same until the topology stabilizes and no event is received in that interval If the first topology change event is received after the current wait interval the SPF calculation is delayed by the amount of time specified as the start interval The subsequent wait intervals continue to follow the dynamic pattern If the first topology change event occurs after the maximum wait interval begins the SPF calculation is again scheduled at the start interval and subsequent wait intervals are reset according to the parameters specified in the timers throttle spf command Notice in Figure 9 that a topology change event was received after the start of the maximum wait time interval and that the SPF intervals have been reset Figure 9 Timer Intervals Reset After Topology Change Event Topology change event 64000 ms 1000 ms 4000 ms 16000 ms 90000 ms 5ms 2000 ms 8000 ms 90000 ms 88279 SPF scheduled at start interval Nonstop Forwarding for OSPF Version
235. he link state database for the network The IS IS NSF feature offers two options when configuring NSF e IETF NSF e Cisco NSF If neighbor routers on a network segment are NSF aware meaning that neighbor routers are running a software version that supports the IETF Internet draft for router restartability they assist an IETF NSF router that is restarting With IETF NSF neighbor routers provide adjacency and link state information to help rebuild the routing information following a failover In Cisco IOS XR software Cisco NSF checkpoints stores persistently all the state necessary to recover from a restart without requiring any special cooperation from neighboring routers The state is recovered from the neighboring routers but only using the standard features of the IS IS routing protocol This capability makes Cisco NSF suitable for use in networks in which other routers have not used the IETF standard implementation of NSF Cisco IOS XR Routing Configuration Guide RC 88 l _ Implementing IS IS on Cisco 10S XR Software Information About Implementing IS IS on Cisco 10S XR Software Hi D Note If you configure IETF NSF on the Cisco IOS XR router and a neighbor router does not support IETF NSF the affected adjacencies flap but nonstop forwarding is maintained to all neighbors that do support IETF NSF A restart reverts to a cold start if no neighbors support IETF NSF Multi Instance IS IS You may configure as many IS IS
236. he same authentication values of the area authentication null Step16 ena Saves configuration changes or 3 e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RP0 CPU0 router config ospf ar if end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP 0 RPO CPU0 router config ospf ar if commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Controlling the Frequency that the Same LSA Is Originated or Accepted for OSPF This task explains how to tune the convergence time of OSPF routes in the routing table when many LSAs need to be flooded in a very short time interval SUMMARY STEPS 1 configure 2 router ospf process name or router ospfv3 process name router id ipv4 address interface type interface instance Do Step 5 Step 6 or both to control the frequency that the same LSA is originated or accepted timers Isa gen interval second
237. he set of all active address families on the router In addition you should explicitly enable single topology operation by configuring it in the IPv6 router address family submode Exceptions to these instructions exist 1 If the address family stanza in the IS IS process contains the adjacency check disable command then an interface is not required to have the address family enabled 2 If the interface is configured to Level 2 only This exception permits the running of IPv4 and IPv6 areas 3 The single topology command is not valid in the ipv4 address family submode Cisco 10S XR Routing Configuration Guide lt Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software The default metric style for single topology is narrow metrics However you can use either wide metrics or narrow metrics How to configure them depends on how single topology is configured If both IPv4 and IPv6 are enabled and single topology is configured the metric style is configured in the address family ipv4 stanza You may configure the metric style in the address family ipv6 stanza but it is ignored in this case If only IPv6 is enabled and single topology is configured then the metric style is configured in the address family ipv6 stanza SUMMARY STEPS 1 configure 2 interface type number 3 ipv4 address address mask or ipv6 address ipv6 prefix prefix length eui 64 or ipv6 address ipv6 addr
238. he system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RP0 CPU0 router config bgp nbr af end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP 0 RPO CPU0 router config bgp nbr af commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Tuning the BGP Best Path Calculation Perform this task to change the default BGP best path calculation behavior SUMMARY STEPS 1 configure router bgp autonomous system number bgp bestpath med missing as worst bgp bestpath med always bgp bestpath med confed bgp bestpath as path ignore N os oO FP BY DS bgp bestpath compare routerid Cisco 10S XR Routing Configuration Guide Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software 8 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP O0 RPO CPU0 router configure
239. hen the OSPFV3 process is doing a graceful restart Helper mode refers to the neighbor routers that continue to forward traffic on established OSPFv3 routes while OSPFV3 is restarting on a neighboring router When the OSPFV3 process starts up it determines whether it must attempt a graceful restart The determination is based on whether graceful restart was previously enabled OSPFv3 does not attempt a graceful restart upon the first time startup of the router When OSPFv3 graceful restart is enabled it changes the purge timer in the RIB to a non zero value See Configuring OSPFv3 Graceful Restart page RC 181 for descriptions of how to enable and configure the Graceful Restart feature During a graceful restart the router does not populate OSPFV3 routes in the RIB It tries to bring up full adjacencies with the fully adjacent neighbors that OSPFv3 had before the restart Eventually the OSPFVv3 process indicates to the RIB that it has converged either for the purpose of terminating the graceful restart for any reason or because it has completed the graceful restart The following are general details about restart mode More detailed information on behavior and certain restrictions and requirements appear in the Graceful Restart Requirements and Restrictions section e Ifthe OSPFv3 attempts a restart too soon after the most recent restart the OSPFv3 process is most likely crashing repeatedly so the new graceful restart stops running To contro
240. hentication and then apply one interface with clear text null authentication amp Note Authentication configured at the interface level overrides authentication configured at the area level and the router process level If an interface does not have authentication specifically configured the interface inherits the authentication parameter value from a higher hierarchical level See the OSPF Hierarchical CLI and CLI Inheritance section on page RC 131 for more information about hierarchy and inheritance Prerequisites If you choose to configure authentication you must first decide whether to configure plain text or MD5 authentication and whether the authentication applies to all interfaces in a process an entire area or specific interfaces See the Route Authentication Methods for OSPF Version 2 section on page RC 135 for information about each type of authentication and when you should use a specific method for your network SUMMARY STEPS 1 configure router ospf process name PF eS N authentication message digest null router id ipv4 address interface type interface instance Cisco 10S XR Routing Configuration Guide Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software area area id interface type instance o on SS exit 10 area area id message digest key key id md5 key clear key encrypted key Repeat Step 7 for each inter
241. his task to configure BGP routing filtering by route policy Prerequisites See the Implementing Routing Policy on Cisco IOS XR Software module of the Cisco IOS XR Routing Configuration Guide for a list of the supported attributes and operations that are valid for inbound and outbound neighbor policy filtering SUMMARY STEPS 1 configure route policy name end policy router bgp autonomous system number neighbor ip address address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast route policy route policy name in out o Nn os FP YY SN end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP O0 RPO CPU0 router configure Step2 route policy name Optional Defines a route policy named drop as 1234 and enters route policy configuration mode Example P 0 RPO CPU0 router config route policy rop as 1234 P 0 RPO CPU0 router config rpl if as path asses through 1234 then P 0 RPO CPU0 router config rpl apply heck communities P 0 RPO CPU0 router config rpl else P 0 RPO CPU0 router config rpl pass P 0 RPO CPU0 router config rpl endif J vaJ VAW Step3 end policy Optional Ends the definition of a route policy and exits route policy configuration mode Example RP 0 RP0 CPU0 router config rpl end policy Cisco IOS XR Routing Configuration Guide RC 62 _ mplement
242. how bgp summary command to display eBGP neighbors that do not have both an inbound and outbound policy for every active address family In the following example such eBGP neighbors are indicated in the output with an exclamation mark RP 0 RPO CPUO router show bgp all all summary Address Family IPv4 Unicast BGP router identifier 10 0 0 1 local AS number 1 BGP generic scan interval 60 secs BGP main routing table version 41 BGP scan interval 60 secs BGP is operating in STANDALONE mode Process RecvTblVer bRIB RIB SendTblVer Speaker 41 41 41 Neighbor Spk AS MsgRcvd MsgSent TblVer InQ OutQ Up Down St PfxRcd 10 0 101 1 0 1 919 925 41 0 0 15 15 08 10 10 0 10T 2 0 2 0 0 0 0 0 00 00 00 Idle Address Family BGP router identifier 10 0 0 1 TPv4 Multicast local AS number 1 BGP generic scan interval 60 secs BGP main routing table version 1 Cisco IOS XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W BGP scan interval 60 secs BGP is operating in STANDALONE mode Process RecvTblVer bRIB RIB SendTblVer Speaker al al al Some configured eBGP neighbors do not have both inbound and outbound policies configured for IPv4 Multicast address family These neighbors will default to sending and or receiving no routes and are marked with in the output below Use the show bgp neighbor lt nbr_address gt
243. icast ipv6 unicast ipv6 multicast route reflector client ono ss FP YS BS end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP O0 RPO CPU0 router configure Step2 router bgp autonomous system number Enters BGP configuration mode allowing you to configure the BGP routing process Example RP 0 RPO CPU0 router config router bgp 120 Step3 bgp cluster id cluster id Configures the local router as one of the route reflectors serving the cluster It is configured with the cluster ID of 192 168 70 1 to identify the cluster Example RP 0 RP0 CPU0 router config bgp bgp cluster id 192 168 70 1 Cisco 10S XR Routing Configuration Guide RC 60 _ mplementing BGP on Cisco 10S XR Software Step 4 Step 5 Step 6 Step 7 Step 8 Command or Action How to Implement BGP on Cisco IOS XR Software W Purpose neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer remote as autonomous system number Example RP 0 RPO CPU0 router config bgp nbr remote as 2002 Creates a neighbor and assigns it a remote autonomous system number of 2002 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example
244. ies for both IPv4 and IPv6 addresses router isis isp net 49 0000 0000 0001 00 address family ipv6 unicast single topology interface POS0 3 0 0 Cisco 10S XR Routing Configuration Guide RC 122 _ Implementing IS IS on Cisco 10S XR Software Configuration Examples for Implementing IS IS on Cisco 10S XR Software Ml address family ipv4 unicast address family ipv6 unicast exit interface POS0 3 0 0 ipv4 address 10 0 1 3 255 255 255 0 ipv6 address 2001 1 64 Configuring Multitopology IS IS for IPv6 Example The following example shows multitopology IS IS being configured in IPv6 You need not enable IS IS for IPv6 globally on the router router isis isp net 49 0000 0000 0001 00 interface POS0 3 0 0 address family ipv6 unicast metric style wide level 1 exit interface POS0 3 0 0 ipv address 2001 1 64 Redistributing IS IS Routes Between Multiple Instances Example The following example shows the attached bit being set for a Level instance This example shows the other Level 1 routers in the area being informed that this router is a suitable candidate to get from the area to the backbone The Level instance is also propagating routes to the Level 2 instance using redistribution Note that the administrative distance is explicitly configured higher on the Level 2 instance to ensure that Level 1 routes are preferred router isis 1 is type level 2 only net 49 0001 0001 0001 0001 00 address family ip
245. ify the same key ID and key that you specified for the virtual link on this router end or commit show ospf process name area id virtual links or show ospfv3 process name virtual links Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Command or Action Purpose show ospf process name or show ospfv3 process name Example RP 0 RPO CPU0 router show ospf or RP O0 RPO CPU0 router show ospfv3 Optional Displays general information about OSPF routing processes e The output displays the router ID of the local router You need this router ID to configure the other end of the link configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router ospf process name or router ospfv3 process name Example RP 0 RPO CPU0 router config router ospf 1 or RP 0 RPO CPU0 router config router ospfv3 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode or Enables OSPFv3 routing for the specified routing process and places the router in router ospfv3 configuration mode Note The process name argument is any alphanumeric string no longer than 40 characters router id ipv4 address interface type interface instance
246. iguration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel1 cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Configuring BGP Route Dampening Perform this task to configure and monitor BGP route dampening SUMMARY STEPS 1 configure router bgp autonomous system number address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast bgp dampening half life reuse suppress max suppress time route policy route policy name oF YS NN end or commit 6 show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics 7 show bgp ipv4 unicast multicast all ipv6 unicast all all unicast
247. iguration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Repeat this task on all other routers in the stub area or NSSA Configuring Neighbors for Nonbroadcast Networks This task explains how to configure neighbors for a nonbroadcast network This task is optional Prerequisites Configuring NBMA networks as either broadcast or nonbroadcast assumes that there are virtual circuits from every router to every other router or a fully meshed network SUMMARY STEPS 1 configure 2 router ospf process name or router ospfv3 process name area area id dead interval seconds hello interval seconds o Nn D oe FP amp interface type number router id ipv4 address interface type interface instance network broadcast non broadcast point to multipoint non broadcast point to point Cisco 10S XR Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software How to Implement OSPF on Cisco 10S XR Software W 9 neighbor ip address priority number poll interval seconds cost number or neighbor ipv6 link local address priority number poll interval seconds cost number database filter all 10 Repeat Step 9 for all neighbors on the interface 11 exit 12 interface type instance 13 neighbor ip address priority numb
248. ing BGP on Cisco 10S XR Software Step 4 Step 5 Step 6 Step 7 Step 8 Command or Action How to Implement BGP on Cisco IOS XR Software Hi Purpose router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Enters neighbor address family configuration mode for the IPv4 address family route policy route policy name in out Example RP 0 RPO CPU0 router config bgp nbr af route policy In Ipv4 in Applies the In Ipv4 policy to inbound IPv4 unicast routes end or commit Example RP 0 RPO CPU0 router config bgp nbr af end or RP 0 RPO CPU0 router config bgp nbr af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session
249. ing routes RC 119 default routes RC 90 description RC 83 enabling RC 91 RC 250 RC 251 RC 253 enabling multicast intact RC 118 functional overview RC 85 grouped configuration RC 85 IPv6 routing RC 86 Level 1 or Level 2 routing configuration RC 91 LSP flooding controlling RC 102 lifetime maximum RC 87 limiting RC 86 MPLS TE configuring RC 110 description RC 89 multi instance IS IS_ RC 89 multitopology configuring RC 98 nonstop forwarding RC 88 configuring RC 106 overload bit configuring RC 87 on router RC 89 policy attach points redistribute RC 234 restrictions configuring RC 84 set SPF interval RC 116 single topology configuring RC 93 single topology IPv6 support RC 87 isis router submode router isis command RC 100 ispf command RC 117 ispf startup delay command RC 117 is type command RC 92 L link state advertisement LSA OSPFv2 RC 137 OSPFv3 RC 129 RC 137 RC 143 local as command RC 56 log adjacency changes command RC 114 RC 147 Isp check interval command RC 103 LSP flooding controlling RC 102 lifetime maximum RC 87 limiting RC 86 mesh group configuration RC 87 on specific interfaces RC 87 Isp gen interval command RC 103 Isp interval command RC 104 Isp mtu command RC 103 Isp password command RC 109 Isp refresh interval command RC 103 Cisco 10S XR Routing Configuration Guide maximum paths command RC 121 max lsp lifetime command RC 103 mesh group command RC 104 message digest
250. ing the is type router configuration command address family ipv4 ipv6 unicast Example RP 0 RPO CPU0 router config isis address family ipv6 unicast Specifies the IPv4 or IPv6 address family and enters router address family configuration mode e This example specifies the unicast IPv6 address family mpls traffic eng level 1 2 Example RP 0 RPO CPU0 router config isis af mpls traffic eng level 1 Configures a router running IS IS to flood MPLS TE link information into the indicated IS IS level Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software Command or Action Purpose Step5 mpls traffic eng router id ip address interface name Example RP 0 RPO CPU0 router config isis af mpls traffic eng router id loopback0O Specifies that the MPLS TE router identifier for the node is the IP address and or name associated with a given interface Step 6 metric style wide level 1 2 Example RP 0 RPO CPU0 router config isis af metric style wide level 1 Configures a router to generate and accept only wide link metrics in the Level area Step7 end or commit Example RP 0 RPO CPU0 router config isis af end or RP 0 RPO CPU0 router config isis af commit Saves configuration changes e When you issue the end command the system prompts you to commit ch
251. inimum time between advertisement runs is 30 seconds For Address Family IPv4 Unicast BGP neighbor version 0 Update group 0 2 eBGP neighbor with no inbound or outbound policy defaults to drop Route refresh request received 0 sent 0 0 accepted prefixes Prefix advertised 0 suppressed 0 withdrawn 0 maximum limit 524288 Threshold for warning message 75 Connections established 0 dropped 0 Cisco 10S XR Routing Configuration Guide RC 10 _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W Last reset 00 00 25 due to BGP neighbor initialized External BGP neighbor not directly connected The inheritance rules used when groups are inheriting configuration from other groups are the same as the rules given for neighbors inheriting from groups Template Inheritance You can use the following show commands described to monitor BGP inheritance information e show bgp neighbors page RC 11 e show bgp af group page RC 12 e show bgp session group page RC 13 e show bgp neighbor group page RC 14 show bgp neighbors Use the show bgp neighbors command to display information about the BGP configuration for neighbors e Use the configuration keyword to display the effective configuration for the neighbor including any settings that have been inherited from session groups neighbor groups or address family groups used by this neighbor e Use the inheritance keyword to
252. ink state database which is done by selecting the route types it wants to import from each protocol It then sets the OSPF parameters of cost and metric type The policy can control how the routes are injected into OSPF by using the set level command The following example shows how to redistribute routes from IS IS instance instance_10 into OSPF instance 1 using the policy OSPF redist The policy sets the metric type to type 2 for all redistributed routes IS IS routes with a tag of 10 have their cost set to 100 and IS IS routes with a tag of 20 have their OSPF cost set to 200 Any IS IS routes not carrying a tag of either 10 or 20 are not be redistributed into the OSPF link state database Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy route policy OSPF redist set metric type type 2 if tag eq 10 then set cost 100 elseif tag eq 20 then set cost 200 else drop endif end policy router ospf 1 redistribute isis instance_10 policy OSPF redist OSPF Attributes and Operators Table 5 summarizes the OSPF attributes and operators Table 5 OSPF Attributes and Operators Attribute Match Set cost n a set destination in n a metric type n a set rib has route in n a route type is n a tag eq ge le set OSPFv3 Policy Attach Points This section describes each of the OSPFV3 policy attach points and provides
253. interface POS 0 1 0 0 l interface POS 0 2 0 0 interface POS 0 3 0 0 area 1 cost 15 interface POS 0 1 0 1 interface POS 0 2 0 1 interface POS 0 3 0 1 l area 4 interface POS 0 1 0 2 cost 20 interface POS 0 2 0 2 interface POS 0 3 0 2 area 6 cost 30 interface POS 0 1 0 3 Cisco 10S XR Routing Configuration Guide I RC 189 Implementing OSPF on Cisco 10S XR Software Configuration Examples for Implementing OSPF on Cisco IOS XR Software interface POS 0 2 0 3 interface POS 0 3 0 3 cost 1 MPLS TE for OSPF Version 2 Example The following example shows how to configure the OSPF portion of MPLS TE However you still need to build an MPLS TE topology and create an MPLS TE tunnel See the Cisco IOS XR MPLS Configuration Guide for information In this example loopback interface 0 is associated with area 0 and area 0 is declared to be an MPLS area interface Loopback 0 ip address 10 10 10 10 255 255 255 0 interface POS 0 2 0 0 ip address 10 1 2 2 255 255 255 0 I router ospf 1 router id 10 10 10 10 nsf auto cost reference bandwidth 10000 area 0 interface POS 0 2 0 0 interface Loopback 0 mpls traffic eng area 0 mpls traffic eng router id Loopback 0 ABR with Summarization for OSPFv3 Example The following example shows the prefix range 2300 16 summarized from area into the backbone router ospfv3 1 router id 192 168 0 217 area 0 interface POS 0
254. ipv6 multicast aggregate address 2012 64 route policy set_next_hop_agg_v6 aggregate address 2013 64 redistribute static route policy set_next_hop_static_v6 neighbor 10 0 101 60 remote as 65000 address family ipv4 unicast address family ipv4 multicast neighbor 10 0 101 61 remote as 65000 address family ipv4 unicast address family ipv4 multicast neighbor 10 0 101 62 remote as 3 address family ipv4 unicast route policy pass all in route policy pass all out address family ipv4 multicast route policy pass all in route policy pass all out neighbor 10 0 101 64 remote as 5 update source Loopback0 address family ipv4 unicast route policy pass all in route policy pass all out address family ipv4 multicast route policy pass all in route policy pass all out Displaying BGP Update Groups Example The following is sample output from the show bgp update group command executed in EXEC mode RP 0O RPO CPUO0 router show bgp update group Update group for IPv4 Unicast index 0 1 Attributes Outbound Route map rm Minimum advertisement interval 30 Messages formatted 2 replicated 2 Neighbors in this update group 10 0 101 92 Update group for IPv4 Unicast index 0 2 Attributes Minimum advertisement interval 30 Messages formatted 2 replicated 2 Neighbors in this update group 10 0 101 91 Cisco 10S XR Routing Configuration Guide Rc Implementing BGP on Cisco IOS XR Software WE Configuration Examples fo
255. isco 10S XR Software Step 5 Step 6 Step 7 Step 8 Step 9 Command or Action How to Implement IS IS on Cisco IOS XR Software Hl Purpose default information originate map name route map Example RP 0 RPO CPU0 router config isis af default information originate Optional Injects a default IPv4 or IPv6 route into an IS IS routing domain e The route map keyword and map name argument specify the conditions under which the IPv4 or IPv6 default route is advertised e Ifthe route map keyword is omitted then the IPv4 or IPv6 default route is unconditionally advertised at Level 2 redistribute isis instance level 1 level 2 level 1 2 metric metric metric type internal external policy policy name Example RP 0 RPO CPU0 router config isis af redistribute isis 2 level 1 Optional Redistributes routes from one IS IS instance into another instance e In this example an IS IS instance redistributes IS IS instance 2 routes into its Level 1 area summary prefix address prefix length 1 2 or level summary prefix ipv6 prefix prefix length level 1 2 Example RP 0 RPO CPU0 router config isis af summary prefix 10 1 0 0 16 level 1 or RP 0 RPO CPU0 router config isis af summary prefix 3003 xxxx 24 level 1 Optional Allows a Level 1 2 router to summarize Level 1 IPv4 and IPv6 prefixes at Level 2 instead of advertising the Level 1 prefixes
256. isements command RC 112 show isis neighbors command RC 116 show isis spf log command RC 118 show isis topology command RC 97 show ospf command RC 162 show ospfv3 command RC 162 show running config command RC 107 shutdown command RC 70 single topology command RC 96 configuring example RC 122 IPv6 support RC 87 set SPF interval RC 116 soft reconfiguration inbound always command RC 69 spf interval command RC 117 SPF throttling configuring OSPFv2 Open Shortest Path First Version 2 RC 170 static route Cisco IOS static route and Cisco IOS XR static route differences RC 247 stub area RC 133 stub area types configuring OSPFv3 RC 147 stub command RC 149 summary prefix command RC 121 RC 169 T table policy command RC 53 timers bgp command RC 34 timers command RC 57 timers lsa gen interval command RC 159 timers lsa group pacing command RC 160 timers lsa min interval command RC 159 timers throttle spf command RC 171 ttl security command RC 57 U update groups BGP configuration RC 18 BGP update generation RC 18 monitor RC 75 update source command RC 57 use command RC 58 vV virtual link transit area OSPFv2 RC 138 virtual link command RC 162 wW weight command RC 39 E Cisco 10S XR Routing Configuration Guide
257. ithin the configuration session Configuring the MED Metric for BGP Perform this task to set the multi exit discriminator MED to advertise to peers for routes that do not already have a metric set routes that were received with no MED attribute SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 default metric value Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software 4 end or commit DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Command or Action How to Implement BGP on Cisco IOS XR Software W Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process default metric value Example RP 0 RPO CPU0 router config bgp default metric 10 Sets the default metric to 10 which is used to set the MED to advertise to peers for routes that do not already have a metric set routes that were received with no MED attribute end or commit Example RP 0 RPO CPU0 router config bgp end or RP 0 RPO CPU0 router config bgp commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes n
258. l Tuning Adjacencies for IS IS on Point to Point Interfaces SUMMARY STEPS This task explains how to enable logging of adjacency state changes alter the timers for IS IS adjacency packets and display various aspects of adjacency state Tuning your IS IS adjacencies increases network stability when links are congested This task is optional For point to point links IS IS sends only a single hello for Level 1 and Level 2 which means that the level modifiers are meaningless on point to point links To modify hello parameters for a point to point interface omit the specification of the level options The options configurable in the interface submode apply only to that interface By default the values are applied to both Level 1 and Level 2 The hello password command can be used to prevent adjacency formation with unauthorized or undesired routers This ability is particularly useful on a LAN where connections to routers with which you have no desire to establish adjacencies are commonly found configure router isis instance id log adjacency changes interface type number hello padding disable sometimes level 1 2 hello interval seconds level 112 hello multiplier multiplier level 11 2 hello password hmac md5 text clear encrypted password level 1 2 send only o 0 N oe FPF W NN end or commit 10 show isis instance instance id adjacency interface type interface instance detail
259. l other interfaces on the router With mesh groups when a new LSP is received over an interface that is part of a mesh group the new LSP is not flooded over the other interfaces that are part of that mesh group Maximum LSP Lifetime and Refresh Interval By default the router sends a periodic LSP refresh every 15 minutes LSPs remain in a database for 20 minutes by default If they are not refreshed by that time they are deleted You can change the LSP refresh interval or maximum LSP lifetime The LSP interval should be less than the LSP lifetime or else LSPs time out before they are refreshed In the absence of a configured refresh interval the software adjusts the LSP refresh interval if necessary to prevent the LSPs from timing out Overload Bit Configuration During Multitopology Operation Because the overload bit applies to forwarding for a single topology it may be configured and cleared independently for IPv4 and IPv6 during multitopology operation For this reason the overload is set from the router address family configuration mode If the IPv4 overload bit is set all routers in the area do not use the router for IPv4 transit traffic However they can still use the router for IPv6 transit traffic Single Topology IPv6 Support Single topology IPv6 support on Cisco IOS XR software allows IS IS for IPv6 to be configured on interfaces along with an IPv4 network protocol All interfaces must be configured with the identical set of net
260. l the period between allowable graceful restarts use the graceful restart interval command A description of how to set this time period appears in the section Configuring the Minimum Time Required Between Restarts page RC 183 e When OSFPv3 starts a graceful restart with the first interface that comes up a timer starts running to limit the duration or lifetime of the graceful restart You can configure this period with the graceful restart lifetime command On each interface that comes up a grace LSA type 11 is flooded to indicate to the neighboring routers that this router is attempting graceful restart The neighbors enter into helper mode e The designated router and backup designated router check of the hello packet received from the restarting neighbor is bypassed because it might not be valid Helper mode is enabled by default When a helper router receives a grace LSA type 11 from a router that is attempting a graceful restart the following events occur e If helper mode has been disabled through the graceful restart helper disable command the router drops the LSA packet e If helper mode is enabled the router enters helper mode if all of the following conditions are met The local router itself is not attempting a graceful restart The local helping router has full adjacency with the sending neighbor The value of lsage link state age in the received LSA is less than the requested grace period The sender
261. le by redistribution then the change cannot be suppressed That is suppression is possible only if both paths were received from external peers 3 If the paths were received from the same peer the paths would have the same router id the change cannot be suppressed The router ID is calculated using rules in the Comparing Pairs of Paths section on page RC 19 4 Ifthe paths have different weights local preferences origins or IGP metrics to their next hops then the change cannot be suppressed Note that all of these values are calculated using the rules in the Comparing Pairs of Paths section on page RC 19 5 Ifthe paths have different length AS paths and the bgp bestpath as path ignore command is not configured then the change cannot be suppressed Again the AS path length is calculated using the rules in the Comparing Pairs of Paths section on page RC 19 6 Ifthe MED of the paths can be compared and the MEDs are different then the change cannot be suppressed The decision as to whether the MEDs can be compared is exactly the same as the rules in the Comparing Pairs of Paths section on page RC 19 as is the calculation of the MED value 7 If all path parameters in steps 1 through 6 do not apply the change can be suppressed Multiprotocol BGP Multiprotocol BGP is an enhanced BGP that carries routing information for multiple network layer protocols and IP multicast routes BGP carries two sets of routes o
262. le delay time minimum hold time and maximum wait time are configured correctly Additional details are displayed about the OSPF process such as the router type and redistribution of routes RP 0 RPO CPU0 router show ospf 1 Routing Process ospf 1 with ID 192 168 4 3 Supports only single TOS TOSO routes Supports opaque LSA It is an autonomous system boundary router Redistributing External Routes from ospf 2 Initial SPF schedule delay 5 msecs Minimum hold time between two consecutive SPFs 100 msecs Maximum wait time between two consecutive SPFs 1000 msecs Minimum LSA interval 5 secs Minimum LSA arrival 1 secs Number of external LSA 0 Checksum Sum 00000000 Number of opaque AS LSA 0 Checksum Sum 00000000 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 1 1 normal 0 stub 0 nssa External flood list length 0 _ mplementing OSPF on Cisco 10S XR Software How to Implement OSPF on Cisco 10S XR Software W Non Stop Forwarding enabled amp Note For a description of each output display field see the show ospf command in the OSPF Commands on Cisco IOS XR Software module in the Cisco IOS XR Routing Command Reference document Configuring Nonstop Forwarding for OSPF Version 2 This task explains how to configure OSPF NSF on your NSF capable router This task is optional Prerequisites OSPF NSF requires that all neighbor networking d
263. le shows how to set up a virtual link to connect the backbone through area 1 for the OSPFv3 topology that consists of areas 0 and 1 and virtual links 10 0 0 217 and 10 0 0 212 ABR 1 Configuration router ospfv3 1 router id 10 0 0 217 area 0 interface POS 0 2 0 1 area 1 virtual link 10 0 0 212 interface POS 0 2 0 0 ABR 2 Configuration router ospfv3 1 router id 10 0 0 212 area 0 interface POS 0 3 0 1 area 1 virtual link 10 0 0 217 interface POS 0 2 0 0 Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HE Where to Go Next Virtual Link Configured with MD5 Authentication for OSPF Version 2 Example The following examples show how to configure a virtual link to your backbone and apply MD5 authentication You must perform the steps described on both ABRs at each end of the virtual link After you explicitly configure the ABRs the configuration is inherited by all interfaces bound to that area unless you override the values and configure them explicitly for the interface To understand virtual links see the Virtual Link and Transit Area for OSPF section on page RC 138 In this example all interfaces on router ABR1 use MDS authentication router ospf ABR1 router id 10 10 10 10 authentication message digest message digest key 100 md5 0 cisco area 0 interface pos 0 2 0 1 interface pos 0 3 0 0 area 1 interface pos 0 3 0 1 virtual link 10 10 5 5 In this example
264. lear mypassword Step6 end Saves configuration changes or A e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RPO CPU0 router config isis if end cancel or RP 0 RPO CPU0 router config isis if commit Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuring MPLS Traffic Engineering for IS IS Prerequisite This task explains how to configure IS IS for MPLS TE This task is optional For a description of the MPLS TE tasks and commands that allow you to configure the router to support tunnels configure an MPLS tunnel that IS IS can use and troubleshoot MPLS TE see the Implementing MPLS Traffic Engineering on Cisco IOS XR Software Your network must support the following Cisco IOS XR software features before you enable MPLS TE for IS IS on your router e MPLS e IP Cisco Express Forwarding CEF
265. les IS IS routing for the specified routing instance and places the router in router configuration mode e You can change the level of routing to be performed by a particular routing instance using the is type router configuration command net network entity title Example RP 0 RPO CPU0 router config isis net 47 0004 004d 0001 0001 0c11 1110 00 Configures NETs for the routing instance e Specify a NET for each routing instance if you are configuring multi instance IS IS You can specify a name for a NET and for an address e This example configures a router with area ID 47 0004 004d 0001 and system ID 0001 0c11 1110 10 e To specify more than one area address specify additional NETs Although the area address portion of the NET differs the system ID portion of the NET must match exactly for all of the configured items interface type instance Example RP 0 RPO CPU0 router config isis interface POS 0 1 0 4 Enters interface configuration mode address family ipv4 unicast Example RP 0 RPO CPU0 router config isis if address family ipv4 unicast Specifies the IPv4 address family and enters interface address family configuration mode e This example specifies the unicast IPv4 address family exit Example RP 0 RPO CPU0 router config if exit Exits interface configuration mode and returns the router to interface configuration mode address family ipv6 unicast Example R
266. lticast all dampening ip address mask length Example RP 0 RPO CPU0 router clear bgp dampening Clears route dampening information and unsuppresses the suppressed routes Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Applying Policy When Updating the Routing Table Perform this task to apply a routing policy to routes being installed into the routing table Prerequisites See the Implementing Routing Policy on Cisco IOS XR Software module of the Cisco IOS XR Routing Configuration Guide for a list of the supported attributes and operations that are valid for table policy filtering SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast 4 table policy policy name 5 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RPO CPU0 router configure Step2 router bgp autonomous system number Enters BGP configuration mode allowing you to configure the BGP routing process Example RP 0 RPO CPU0 router config router bgp 120 Step3 address family ipv4 unicast ipv4 multicast Enters global address family configuration mode for the ipv6 unicast ipv6 multicast IPv4 address family Example RP 0 RPO CPU0 router config bgp address family ipv4 unicast
267. mance of your network is impaired but most business operations remain functional You and Cisco will commit resources during normal business hours to restore service to satisfactory levels Severity 4 S4 You require information or assistance with Cisco product capabilities installation or configuration There is little or no effect on your business operations Obtaining Additional Publications and Information Information about Cisco products technologies and network solutions is available from various online and printed sources e Cisco Marketplace provides a variety of Cisco books reference guides documentation and logo merchandise Visit Cisco Marketplace the company store at this URL http www cisco com go marketplace Cisco 10S XR Routing Configuration Guide BH Preface HZ Obtaining Additional Publications and Information Cisco Press publishes a wide range of general networking training and certification titles Both new and experienced users will benefit from these publications For current Cisco Press titles and other information go to Cisco Press at this URL http www ciscopress com Packet magazine is the Cisco Systems technical user magazine for maximizing Internet and networking investments Each quarter Packet delivers coverage of the latest industry trends technology breakthroughs and Cisco products and solutions as well as network deployment and troubleshooting tips configuration examples
268. matching length is 32 for IPv4 and 128 for IPv6 Otherwise if neither minimum nor maximum is specified the default maximum is the mask length The prefix set itself is a comma separated list of prefix match specifications The following are examples prefix set legal ipv4 prefix examples 10 0 1 1 10 0 2 0 24 10 0 3 0 24 ge 28 10 0 4 0 24 le 28 10 0 5 0 24 ge 26 le 30 10 0 6 0 24 eq 28 end set prefix set legal ipv6 prefix examples 2001 0 0 1 64 2001 0 0 2 64 ge 96 2001 0 0 2 64 ge 96 le 100 2001 0 0 2 64 eq 100 end set The first element of the prefix set matches only one possible value 10 0 1 1 32 or the host address 10 0 1 1 The second element matches only one possible value 10 0 2 0 24 The third element matches a range of prefix values from 10 0 3 0 28 to 10 0 3 255 32 The fourth element matches a range of values from 10 0 4 0 24 to 10 0 4 240 28 The fifth element matches prefixes in the range from 10 0 5 0 26 to 10 0 5 252 30 The sixth element matches any prefix of length 28 in the range from 10 0 6 0 28 through 10 0 6 240 28 Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy i The following prefix set consists entirely of invalid prefix match specifications prefix set ILLEGAL PREFIX EXAMPLES 10 1 1 1 ge 16 10 1 2 1 le 16 10 1 3 0 24 le 23 10 1 4 0 24 ge 33 10 1 5 0 25 ge 29 le 28 end set Neither the minimum lengt
269. mation About Implementing BGP on Cisco IOS XR Software W The BGP best path algorithm implementation is in three parts e Part 1 Compares two paths to determine which is better e Part 2 Iterates over all paths and determines which order to compare the paths to select the overall best path e Part 3 Determines whether the old and new best paths differ enough so that the new best path should be used amp Note The order of comparison determined by Part 2 is important because the comparison operation is not transitive that is if three paths A B and C exist such that when A and B are compared A is better and when B and C are compared B is better it is not necessarily the case that when A and C are compared A is better This nontransitivity arises because the multi exit discriminator MED is compared only among paths from the same neighboring autonomous system AS and not among all paths Comparing Pairs of Paths The following steps are completed to compare two paths and determine the better path 1 If either path is invalid for example it has the maximum possible MED value or it has an unreachable nexthop then the other path is chosen provided that the path is valid 2 Ifthe paths have unequal weights the path with the highest weight is chosen Note the weight is entirely local to the router and can be set with the weight command or using a routing policy 3 Ifthe paths have unequal local preferences
270. mmand becomes a powerful tool for reducing repetitive configuration Policies do not become useful until they are applied to routes and for policies to be applied to routes they need to be made known to routing protocols In BGP for example there are several situations where policies can be used the most common of these is defining import and export policy The policy attach point is the point in which an association is formed between a specific protocol entity in this case a BGP neighbor and a specific named policy It is important to note that a verification step happens at this point Each time a policy is attached the given policy and any policies it may apply are checked to ensure that the policy can be validly used at that attach point For example if a user defines a policy that sets the IS IS level attribute and then attempts to attach this policy as an inbound BGP policy the attempt would be rejected because BGP routes do not carry IS IS attributes Likewise when policies are modified that are in use the attempt to modify the policy is verified against all current uses of the policy to ensure that the modification is compatible with the current uses Each protocol has a distinct definition of the set of attributes commands that compose a route For example BGP routes may have a community attribute which is undefined in OSPF Routes in IS IS have a level attribute which is unknown to BGP Routes carried internally in the RIB may have
271. mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Step5 configure Example RP O0 RPO CPU0 router configure Enters global configuration mode Step 6 router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process Step 7 bgp router id ip address interface type interface instance Example RP 0 RPO CPU0 router config bgp bgp router id 192 168 70 24 Configures the local router with a router id of 192 168 70 24 Step8 neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer Cisco IOS XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Step 9 Step 10 Step 11 Step 12 Command or Action How to Implement BGP on Cisco IOS XR Software W Purpose remote as autonomous system number Example RP 0 RPO CPU0 router co
272. multicast documentation for more information on using and configuring multicast RIB processes ipv4_rib and ipv6_rib run on the RP card If process placement functionality is available and supported by multiple RPs in the router RIB processes can be placed on any available node Cisco 10S XR Routing Configuration Guide Implementing and Monitoring RIB on Cisco 10S XR Software W How to Deploy and Monitor RIB How to Deploy and Monitor RIB To deploy and monitor RIB you must understand the following concepts e Verifying RIB Configuration Using the Routing Table page RC 198 required e Verifying Networking and Routing Problems page RC 198 required Verifying RIB Configuration Using the Routing Table This task verifies the RIB configuration to ensure that RIB is running on the RP and functioning properly by checking the routing table summary and details SUMMARY STEPS 1 show route afi all ipv4 ipv6 unicast multicast safi all summary 2 show route protocol process id afi all ipv4 ipv6 unicast multicast safi all ip address mask DETAILED STEPS Command or Action Purpose Step 1 show route afi all ipv4 ipv6 unicast Displays route summary information on the specified multicast safi all summary routing table e The default table summarized is the IPv4 unicast Example routing table RP 0 RPO CPU0 router show route summary Step2 show route protocol process id a
273. mz link bandwidth command RC 56 Draft ietf idr bgp4 24 txt BGP RC 80 RC 244 Draft ietf idr bgp4 mib 15 txt BGP RC 80 draft ietf idr cease subcode 05 txt RC 80 Draft ietf isis igp p2p over lan 05 txt Point to point operation over LAN RC 124 Draft ietf isis ipv6 05 txt Routing IPv6 with IS IS RC 124 Draft ietf isis restart 04 txt Restart Signalling for IS IS RC 124 Draft ietf isis traffic 05 txt IS IS Extensions for Traffic Engineering RC 124 Draft ietf isis wg multi topology 06 txt M ISIS Multi Topology MT Routing in IS IS RC 124 ebgp multihop command RC 56 end policy command RC 30 EXEC mode RC 13 clear bgp flap statistics command RC 50 clear bgp flap statistics reexp command RC 51 clear bgp flap statistics route policy command RC 51 clear bgp soft in command RC 71 clear bgp soft out command RC 72 clear ospf command RC 181 clear ospfv3 command RC 181 show bgp af group command RC 12 RC 13 show bgp cidr only command RC 74 show bgp community command RC 74 show bgp count only command RC 74 show bgp flap statistics command RC 50 show bgp flap statistics reexp command RC 50 show bgp flap statistics route policy command RC 50 show bgp inheritance command RC 12 show bgp neighbor command RC 11 show bgp neighbor group command RC 14 RC 75 show bgp neighbors command RC 74 show bgp paths command RC 75 Index W show bgp reexp command RC 74 show bgp summary command RC 75 show isis adjacency command RC 101 show isi
274. n Cisco IOS XR Software DETAILED STEPS Step 1 Step 2 Step 3 Command or Action Configuration Examples for Implementing Routing Policy W Purpose edit route policy prefix set as path set community set extended community set name Example RP 0 RPO CPU0 router edit route policy samplel Identifies the route policy prefix set AS path set community set or extended community set name to be modified e A copy of the route policy prefix set AS path set community set or extended community set is copied to a temporary file and the microemacs editor is launched When you finish editing the policy or set save the changes by using the save buffer command X S Control X Control S To commit the changed configuration e save the buffer Control X Control S e exit MicroEmacs Control X Control C show rpl route policy name detail Example RP 0 RPO CPU0 router show rpl route policy sample2 Optional Displays the configuration of a specific named route policy e Use the detail keyword to display all policies and sets that a policy uses show rpl prefix set name Example RP O0 RPO CPU0 router show rpl prefix set prefixsetl Optional Displays the contents of a named prefix set e To display the contents of a named AS path set community set or extended community set replace the prefix set keyword with as path set community set or extcommunity set respectively Co
275. n about RIB on the Cisco IOS XR software and complete descriptions of RIB commands listed in this module see the Related Documents of this module To locate documentation for other commands that might appear during the execution of a configuration task search online in the Cisco IOS XR software master command index Feature History for Implementing and Monitoring RIB on Cisco IOS XR Software Release Modification Release 2 0 This feature was introduced on the Cisco CRS 1 Release 3 0 No modification Release 3 2 Support was added for the Cisco XR 12000 Series Router e Prerequisites for Implementing RIB on Cisco IOS XR Software page RC 196 e Information About RIB Configuration page RC 196 e How to Deploy and Monitor RIB page RC 198 e Configuration Examples for RIB Monitoring page RC 200 e Where to Go Next page RC 202 e Additional References page RC 203 Cisco 10S XR Routing Configuration Guide E Implementing and Monitoring RIB on Cisco 10S XR Software HI Prerequisites for Implementing RIB on Cisco IOS XR Software Prerequisites for Implementing RIB on Cisco IOS XR Software e To use this command you must be in a user group associated with a task group that includes the proper task IDs For detailed information about user groups and task IDs see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide e RIB is distributed with the base
276. n groups and address family groups and can comprise the complete configuration for a neighbor After a neighbor group is configured a neighbor can inherit the configuration of the group using the use command If a neighbor is configured to use a neighbor group the neighbor inherits the entire BGP configuration of the neighbor group The following example shows how to enter neighbor group configuration mode RP 0 RPO CPU0 router config router bgp 140 P 0 RPO CPU0 router config bgp neighbor group nbrgroup1 P 0 RPO CPU0 router config bgp nbrgrp DA The following example shows how to enter neighbor group address family configuration mode RP 0 RPO CPU0 router config router bgp 140 RP 0 RPO CPU0 router config bgp neighbor group nbrgroup1 RP 0 RPO CPU0 router config bgp nbrgrp address family ipv4 unicast RP 0 RPO CPUO router config bgp nbrgrp af e However a neighbor does not inherit all of the configuration from the neighbor group if items are explicitly configured for the neighbor In addition some part of the configuration of the neighbor group could be hidden if a session group or address family group was also being used Configuration grouping has the following effects in Cisco IOS XR software Cisco IOS XR Routing Configuration Guide RC6 _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W e Commands entered at the sessi
277. n other words comparison operators always run on the initial data in the route Intermediate modifications of the route attributes do not have a cascading effect on the evaluation of the policy Take the following example Cisco IOS XR Routing Configuration Guide EAJ Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy i if med eq 12 then set med 42 if med eq 42 then drop endif endif This policy never executes the drop statement because the second test med eq 42 sees the original unmodified value of the MED in the route Because the MED has to be 12 to get to the second test the second test always returns false Default Drop Disposition Control Flow All route policies have a default action to drop the route under evaluation unless the route has been modified by a policy action or explicitly passed Applied nested policies implement this disposition as though the applied policy were pasted into the point where it is applied Consider a policy to allow all routes in the 10 network and set their local preference to 200 while dropping all other routes You might write the policy as follows route policy two if destination in 10 0 0 0 8 ge 8 le 32 then set local preference 200 endif end policy route policy one apply two end policy It may appear that policy one drops all routes because it neither contains an explicit pass statement nor modifies a route attribute
278. name in out Attaches the route policy which must be well formed and predefined Example RP 0 RPO CPU0 router config bgp nbr af route policy examplel in Step6 end Saves configuration changes or e When you issue the end command the system commit prompts you to commit changes Uncommitted changes found commit them Example before exiting yes no cancel RP 0 RP0 CPU0 router config bgp nbr af end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP 0 RPO CPU0 router config bgp nbr af commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Modifying a Routing Policy Using the Microemacs Editor This task explains how to modify an existing routing policy using the microemacs editor SUMMARY STEPS 1 edit route policy prefix set as path set community set extended community set name 2 show rpl route policy name detail 3 show rpl prefix set name Cisco IOS XR Routing Configuration Guide EZI Implementing Routing Policy o
279. nd Configuring Level 1 or Level 2 Routing RC 91 Configuring Single Topology for IS IS RC 93 Configuring Multitopology for IS IS RC 98 Controlling LSP Flooding for IS IS RC 102 Configuring Nonstop Forwarding for IS IS_ RC 106 Configuring Authentication for IS IS_ RC 108 Configuring MPLS Traffic Engineering for IS IS_ RC 110 Tuning Adjacencies for IS IS on Point to Point Interfaces RC 113 Setting SPF Interval for a Single Topology IPv4 and IPv6 Configuration RC 116 Enabling Multicast Intact for IS IS RC 118 Cisco 10S XR Routing Configuration Guide E E Contents Customizing Routes for IS IS_ RC 119 Configuration Examples for Implementing IS IS on Cisco IOS XR Software RC 122 Configuring Single Topology IS IS for IPv6 Example RC 122 Configuring Multitopology IS IS for IPv6 Example RC 123 Redistributing IS IS Routes Between Multiple Instances Example RC 123 Where to Go Next RC 124 Additional References RC 124 Related Documents RC 124 Standards RC 124 MIBs RC 124 RFCs RC 125 Technical Assistance RC 125 Implementing OSPF on Cisco IOS XR Software RC 127 Contents RC 127 Prerequisites for Implementing OSPF on Cisco IOS XR Software RC 128 Information About Implementing OSPF on Cisco IOS XR Software RC 128 OSPF Functional Overview RC 129 Key Features Supported in the Cisco IOS XR OSPF Implementation RC 130 Comparison of Cisco IOS XR OSPFv3 and OSPFv2 RC 131 Importing Addresses into OSPFv3 RC 131 OSPF Hiera
280. ne set for unicast routing and one set for multicast routing The routes associated with multicast routing are used by the Protocol Independent Multicast PIM feature to build data distribution trees Cisco 10S XR Routing Configuration Guide Implementing BGP on Cisco IOS XR Software Information About Implementing BGP on Cisco 10S XR Software Multiprotocol BGP is useful when you want a link dedicated to multicast traffic perhaps to limit which resources are used for which traffic Multiprotocol BGP allows you to have a unicast routing topology different from a multicast routing topology providing more control over your network and resources In BGP the only way to perform interdomain multicast routing was to use the BGP infrastructure that was in place for unicast routing Perhaps you want all multicast traffic exchanged at one network access point NAP If those routers were not multicast capable or there were differing policies for which you wanted multicast traffic to flow multicast routing could not be supported without multiprotocol BGP Note It is possible to configure BGP peers that exchange both unicast and multicast network layer reachability information NLRI but you cannot connect multiprotocol BGP clouds with a BGP cloud That is you cannot redistribute multiprotocol BGP routes into BGP Figure illustrates simple unicast and multicast topologies that are incongruent and therefore are not possible without
281. nfig route ipv6 unicast 2001 0DB8 32 2001 0DB8 3000 1 A fully specified route is valid that is a candidate for insertion into the routing table when the specified interface is IPv4 or IPv6 enabled and up Floating Static Routes Floating static routes are static routes that are used to back up dynamic routes learned through configured routing protocols A floating static route is configured with a higher administrative distance than the dynamic routing protocol it is backing up As a result the dynamic route learned through the routing protocol is always preferred to the floating static route If the dynamic route learned through the routing protocol is lost the floating static route is used in its place The following example shows how to define a floating static route RP 0 RPO CPU0 router config route ipv6 unicast 2001 0DB8 32 2001 0DB8 3000 1 210 Any of the three types of static routes can be used as a floating static route A floating static route must be configured with an administrative distance that is greater than the administrative distance of the dynamic routing protocol because routes with smaller administrative distances are preferred Note By default static routes have smaller administrative distances than dynamic routes so static routes preferred to dynamic routes How to Implement Static Routes on Cisco IOS XR Software This section contains the following procedures e Configuring a Static Route page R
282. nfig bgp nbr remote as 2002 Creates a neighbor and assigns it a remote autonomous system number of 2002 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Enters global address family configuration mode for the IPv4 address family route policy route policy name in out Example RP 0 RPO CPU0 router config bgp nbr af route policy In Ipv4 in Optional Applies the In Ipv4 policy to inbound IPv4 unicast routes end or commit Example RP 0 RPO CPU0 router config bgp nbr af end or RP 0 RPO CPU0 router config bgp nbr af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuring a
283. nfiguration Examples for Implementing Routing Policy This section provides the following configuration examples e Routing Policy Definition Example page RC 241 e Simple Inbound Policy Example page RC 242 e Modular Inbound Policy Example page RC 243 e Translating Cisco IOS Route Maps to Cisco IOS XR Routing Policy Language Example page RC 244 Routing Policy Definition Example In the following example a BGP route policy named sample is defined using the route policy name command The policy compares the network layer reachability information NLRI to the elements in the prefix set test If it evaluates to true the policy performs the operations in the then clause If it evaluates to false the policy performs the operations in the else clause that is sets the MED value to 200 and adds the community 2 100 to the route The final steps of the example commit the configuration to the router exit configuration mode and display the contents of route policy sample1 Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software WE Configuration Examples for Implementing Routing Policy configure route policy samplel if destination in test then drop else set med 200 set community 2 100 additive endif end policy end show config running route policy samplel Building configuration route policy samplel if destination in test then drop else set med 200 set commu
284. nfiguration Examples for RIB Monitoring RC 200 Output of show route Command Example RC 200 Output of show route backup Command Example RC 201 Output of show route best local Command Example RC 201 Output of show route connected Command Example RC 201 Output of show route local Command Example RC 201 Output of show route longer prefixes Command Example _ RC 202 Output of show route next hop Command Example RC 202 Where to Go Next RC 202 Additional References RC 203 Related Documents RC 203 Standards RC 203 MIBs RC 203 RFCs RC 204 Technical Assistance RC 204 Implementing Routing Policy on Cisco 10S XR Software RC 205 Contents RC 205 Prerequisites for Implementing Routing Policy RC 206 Information About Implementing Routing Policy RC 206 Routing Policy Language RC 206 Routing Policy Configuration Basics RC 213 Policy Definitions RC 213 Parameterization RC 214 Semantics of Policy Application RC 215 Policy Statements RC 219 Attach Points RC 223 Attached Policy Modification RC 235 Nonattached Policy Modification RC 235 How to Implement Routing Policy RC 237 Defining a Route Policy RC 237 Attaching a Routing Policy toa BGP Neighbor RC 238 Modifying a Routing Policy Using the Microemacs Editor RC 240 Configuration Examples for Implementing Routing Policy RC 241 Routing Policy Definition Example RC 241 Cisco IOS XR Routing Configuration Guide Contents W Simple Inbound Policy Example RC 242 Modular Inbound Poli
285. nfigured when the circuit type level 1 2 router is configured as only level 1 2 and you want to constrain an interface to form only level 1 or level 2 only adjacencies Step12 address family ipv4 ipv6 unicast Specifies the IPv4 or IPv6 address family and enters interface address family configuration mode Example e This example specifies the unicast IPv6 address family RP 0 RPO CPU0 router config isis if on the interface address family ipv6 unicast Step 13 end Saves configuration changes or i e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RP0 CPU0 router config isis af end cancel or Entering yes saves configuration changes to the RECO REU CRUDS OUEST Conf g tere arya commit running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Step14 show isis instance instance id interface Optional Displays information about the IS IS interface type instance det
286. ng Configuration Guide i Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp address family ipv4 unicast Enters global address family configuration mode for the IPv4 address family network ip address prefix length ip address mask backdoor Example RP 0 RPO CPU0 router config bgp af network 172 20 0 0 16 Configures the local router to originate and advertise the IPv4 unicast network 172 20 0 0 16 end or commit Example RP 0 RPO CPU0 router config bgp af end or RP 0 RPO CPU0 router config bgp af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel1 cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode
287. ng Configuration Guide mB RC27 Implementing BGP on Cisco IOS XR Software W How to Implement BGP on Cisco 10S XR Software Tuning the BGP Best Path Calculation page RC 39 optional Indicating BGP Backdoor Routes page RC 41 optional Configuring Aggregate Addresses page RC 43 optional Redistributing iBGP Routes into IGP page RC 44 optional Redistributing Prefixes into Multiprotocol BGP page RC 46 optional Configuring BGP Route Dampening page RC 48 optional Applying Policy When Updating the Routing Table page RC 52 optional Setting BGP Administrative Distance page RC 53 optional Configuring a BGP Neighbor Group page RC 55 optional Configuring a BGP Neighbor page RC 58 required Configuring a Route Reflector for BGP page RC 60 optional Configuring BGP Route Filtering by Route Policy page RC 62 optional Disabling Next Hop Processing on BGP Updates page RC 64 optional Configuring BGP Community and Extended Community Filtering page RC 65 optional Configuring Software to Store Updates from a Neighbor page RC 67 optional Disabling a BGP Neighbor page RC 69 optional Resetting Neighbors Using BGP Dynamic Inbound Soft Reset page RC 71 optional Resetting Neighbors Using BGP Outbound Soft Reset page RC 71 optional Resetting Neighbors Using BGP Hard Reset page RC 72 optional Clearing Caches Tables and Databases page RC 73 optional Displaying System and Network Statistics page RC 73 op
288. ng you to configure the BGP routing process Example RP 0 RPO CPU0 router config router bgp 120 Step3 address family ipv4 unicast ipv4 multicast Enters global address family configuration mode for the ipv6 unicast ipv6 multicast IPv4 address family Example RP 0 RPO CPU0 router config bgp address family ipv4 unicast Cisco 10S XR Routing Configuration Guide RC 46 _ mplementing BGP on Cisco 10S XR Software Step 4 Step 5 Command or Action How to Implement BGP on Cisco IOS XR Software Hl Purpose redistribute connected metric metric value route policy route policy name or redistribute isis process id level 1 1 inter area 2 metric metric value route policy route policy name or redistribute ospf process id match external 1 2 internal nssa external 1 2 metric metric value route policy route policy name or redistribute ospfv3 process id match external 1 2 internal nssa external 1 2 metric metric value route policy route policy name or redistribute static metric metric value route policy route policy name Example RP 0 RPO CPU0 router config bgp af redistribute ospf 110 Causes IPv4 unicast OSPF routes from OSPF instance 110 to be redistributed into BGP end or commit Example RP 0 RPO CPU0 router config bgp af end or RP 0 RPO CPU0 router config bgp af commit Saves conf
289. nity 2 100 additive endif end policy Simple Inbound Policy Example The following policy discards any route whose network layer reachability information NLRI specifies a prefix longer than 24 and any route whose NLRI specifies a destination in the address space reserved by RFC 1918 For all remaining routes it sets the MED and local preference and adds a community to the list in the route For routes whose community lists include any values in the range from 101 202 to 106 202 that have a 16 bit tag portion containing the value 202 the policy prepends autonomous system number 2 twice and adds the community 2 666 to the list in the route Of these routes if the MED is either 666 or 225 then the policy sets the origin of the route to incomplete and otherwise sets the origin to IGP For routes whose community lists do not include any of the values in the range from 101 202 to 106 202 the policy adds the community 2 999 to the list in the route prefix set too specific 0 0 0 0 0 ge 25 le 32 end set prefix set rfc1918 10 0 0 0 8 le 32 172 16 0 0 12 le 32 192 168 0 0 16 le 32 end set route policy inbound tx if destination in too specific or destination in rfc1918 then drop endif set med 1000 set local preference 90 set community 2 1001 additive if community matches any 101 106 202 prepend as path 2 2 set community 2 666 additive if med is 666 or med is 225 then set origin incomplete else set o
290. nt or Website are the property of their respective owners The use of the word partner does not imply a partnership relationship between Cisco and any other company 0502R Cisco IOS XR Routing Configuration Guide Copyright 2005 Cisco Systems Inc All rights reserved Preface xi Document Revision History xi Obtaining Documentation xii Cisco com xii Product Documentation DVD xii Ordering Documentation xii Documentation Feedback xiii Cisco Product Security Overview xiii Reporting Security Problems in Cisco Products xiii Obtaining Technical Assistance xiv Cisco Technical Support amp Documentation Website xiv Submitting a Service Request xv Definitions of Service Request Severity xv Obtaining Additional Publications and Information xv Implementing BGP on Cisco IOS XR Software RC 1 Contents RC 1 Prerequisites for Implementing BGP on Cisco IOS XR Software RC 2 Information About Implementing BGP on Cisco IOS XR Software RC 2 BGP Functional Overview RC 2 BGP Router Identifier RC 3 BGP Default Limits RC 3 BGP Validation of Local Next Hop Addresses RC 4 BGP Configuration RC 4 No Default Address Family RC 15 Routing Policy Enforcement RC 16 Table Policy RC 18 Update Groups RC 18 BGP Best Path Algorithm RC 18 Multiprotocol BGP RC 21 Route Dampening RC 23 BGP Routing Domain Confederation RC 24 BGP Route Reflectors RC 24 Default Address Family for show Commands RC 27 Cisco IOS XR Routing Configuration Guide m E Con
291. o cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Configuring BGP Weights Perform this task to assign a weight to routes received from a neighbor A weight is a number that you can assign to a path so that you can control the best path selection process If you have particular neighbors that you want to prefer for most of your traffic you can use the weight command to assign a higher weight to all routes learned from that neighbor Restrictions The clear bgp command must be used for the newly configured weight to take effect SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 neighbor ip address 4 remote as autonomous system number 5 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast 6 weight weight value 7 end or c
292. obal configuration mode Cisco 10S XR Routing Configuration Guide RC 236 Implementing Routing Policy on Cisco IOS XR Software How to Implement Routing Policy Hi How to Implement Routing Policy This section contains the following procedures e Defining a Route Policy page RC 237 required e Attaching a Routing Policy to a BGP Neighbor page RC 238 required e Modifying a Routing Policy Using the Microemacs Editor page RC 240 optional Defining a Route Policy This task explains how to define a route policy amp Note If you want to modify an existing routing policy using the command line interface CLI you must redefine the policy by completing this task SUMMARY STEPS 1 configure 2 route policy name 3 end policy 4 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RP0 CPU0 router configure Step2 route policy name Enters route policy configuration mode e After the route policy has been entered a group of Example commands can be entered to define the route policy RP 0 RP0 CPU0 router config route policy sample1 Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HZ How to Implement Routing Policy Command or Action Purpose Step3 end policy Ends the definition of a route policy and exits route policy configuration mode Example RP 0 RPO
293. ocol BGP IMBGP in the figure Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W A multicast routing protocol such as PIM uses the multicast BGP database to perform Reverse Path Forwarding RPF lookups for multicast capable sources Thus packets can be sent and accepted on the multicast topology but not on the unicast topology Figure 2 Multicast BGP Environment Router B AS 200 Unicast ED Multicast IMBGP router Seon eee ally NAP IMBGP Unicast router Multicast router SnG AS 100 Unicast route gt lt Multicast route 6 11754 Router A Route Dampening Route dampening is a BGP feature that minimizes the propagation of flapping routes across an internetwork A route is considered to be flapping when it is repeatedly available then unavailable then available then unavailable and so on For example consider a network with three BGP autonomous systems autonomous system 1 autonomous system 2 and autonomous system 3 Suppose the route to network A in autonomous system 1 flaps it becomes unavailable Under circumstances without route dampening the eBGP neighbor of autonomous system 1 to autonomous system 2 sends a withdraw message to autonomous system 2 The border router in autonomous system 2 in turn propagates the withdrawal message to auton
294. ode The examples are based on the following session group configuration RP 0 RPO CPU0O router config router bgp 140 RP 0 RPO CPU0 router config bgp session group GROUP_1 RP 0 RPO CPU0 router config bgp sngrp use session group GROUP_2 RP 0 RPO CPU0 router config bgp sngrp update source Loopback 0 RP 0 RPO CPU0 router config bgp sngrp exit RP 0 RPO CPU0 router config bgp session group GROUP_2 RP 0 RPO CPU0 router config bgp sngrp use session group GROUP_3 RP 0 RPO CPU0 router config bgp sngrp ebgp multihop 2 RP 0 RPO CPU0 router config bgp sngrp exit RP 0 RPO CPU0 router config bgp session group GROUP_3 RP 0 RPO CPU0 router config bgp sngrp dmz link bandwidth The following is sample output from the show bgp session group command with the configuration keyword in EXEC mode Cisco 10S XR Routing Configuration Guide prcs Implementing BGP on Cisco IOS XR Software Information About Implementing BGP on Cisco 10S XR Software RP 0 RPO CPU0 router show bgp session group GROUP_1 configuration session group GROUP_1 ebgp multihop 2 s GROUP_2 update source LoopbackO dmz link bandwidth s GROUP_2 s GROUP_3 The following is sample output from the show bgp session group command with the inheritance keyword showing that the GROUP_1 session group inherits session parameters from the GROUP_3 and GROUP_2 session groups RP O0 RPO CPU0 router show bgp session g
295. ode is available for entering address family specific neighbor configurations In Cisco IOS XR the configuration is as follows Router config bgp af neighbor 2002 Router config bgp nbr remote as 2002 Router config bgp nbr address family ipv6 unicast Router config bgp nbr af next hop self Router config bgp nbr af route policy one in e You must enter neighbor specific IPv4 or IPv6 commands in neighbor address family configuration submode In Cisco IOS XR software the configuration is as follows Router config bgp router bgp 109 Router config bgp neighbor 192 168 40 24 Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HZ Information About Implementing BGP on Cisco 10S XR Software Router config bgp nbr remote as 1 Router config bgp nbr address family ipv4 unicast Router config bgp nbr af maximum prefix 1000 Configuration Templates The af group session group and neighbor group configuration commands provide template support for the neighbor configuration in Cisco IOS XR software The af group command is used to group address family specific neighbor commands within an IPv4 or IPv6 address family Neighbors that have the same address family configuration are able to use the address family group af group name for their address family specific configuration A neighbor inherits the configuration from an address family group by way of the use command If
296. of the grace LSA is the same as the originator of the grace LSA Cisco 10S XR Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software Information About Implementing OSPF on Cisco 10S XR Software W Upon entering helper mode a router performs its helper function for a specific period of time This time period is the lifetime value from the router that is in restart mode minus the value of Isage in the received grace LSA If the graceful restart succeeds in time the helper s timer is stopped before it expires If the helper s timer does expire the adjacency to the restarting router is brought down and normal OSPFv3 functionality resumes The dead timer is not honored by the router that is in helper mode A router in helper mode ceases to perform the helper function in any of the following cases The helper router is able to bring up a FULL adjacency with the restarting router The local timer for the helper function expires Graceful Restart Requirements and Restrictions The requirements for supporting the Graceful Restart feature include Cooperation of a router s neighbors during a graceful restart In relation to the router on which OSPFV3 is restarting each router is called a helper All neighbors of the router that does a graceful restart must be capable of doing a graceful restart A graceful restart does not occur upon the first time startup of a router OSPFv3 neighbor information and d
297. oftware How to Implement IS IS on Cisco IOS XR Software Hl How to Implement IS IS on Cisco IOS XR Software This section contains the following procedures amp Enabling IS IS and Configuring Level 1 or Level 2 Routing page RC 91 required Configuring Single Topology for IS IS page RC 93 required Configuring Multitopology for IS IS page RC 98 optional Controlling LSP Flooding for IS IS page RC 102 optional Configuring Nonstop Forwarding for IS IS page RC 106 optional Configuring Authentication for IS IS page RC 108 optional Configuring MPLS Traffic Engineering for IS IS page RC 110 optional Tuning Adjacencies for IS IS on Point to Point Interfaces page RC 113 optional Setting SPF Interval for a Single Topology IPv4 and IPv6 Configuration page RC 116 optional Enabling Multicast Intact for IS IS page RC 118 optional Note To save configuration changes you must commit changes when the system prompts you Enabling IS IS and Configuring Level 1 or Level 2 Routing amp This task explains how to enable IS IS and configure the routing level for an area Note Prerequisites SUMMARY STEPS Configuring the routing level in Step 4 is optional but is highly recommended to establish the proper level of adjacencies Although you can configure IS IS before you configure an IP address no IS IS routing occurs until at least one IP address is configured oF w N configure route
298. ommand syntax command modes command history defaults usage guidelines and examples Cisco IOS XR Routing Command Reference Release 3 2 Standards Standards Title draft ietf idr bgp4 26 txt A Border Gateway Protocol 4 by Y Rekhter T Li S Hares draft ietf idr bgp4 mib 15 txt Definitions of Managed Objects for the Fourth Version of Border Gateway Protocol BGP 4 by J Hass and S Hares draft ietf idr cease subcode 05 txt Subcodes for BGP Cease Notification Message by Enke Chen V Gillet MIBs MIBs MIBs Link e BGP4 MIB e CISCO BGP4 MIB To locate and download MIBs for selected platforms using Cisco IOS XR software use the Cisco MIB Locator found at the following URL http cisco com public sw center netmgmt cmtk mibs shtml RFCs RFCs Title RFC 1997 BGP Communities Attribute RFC 2385 Protection of BGP Sessions via the TCP MD5 Signature Option RFC 2439 BGP Route Flap Damping RFC 2545 Use of BGP 4 Multiprotocol Extensions for IPv6 Inter Domain Routing RFC 2796 BGP Route Reflection An Alternative to Full Mesh IBGP RFC 2858 Multiprotocol Extensions for BGP 4 RFC 2918 Route Refresh Capability for BGP 4 Cisco IOS XR Routing Configuration Guide RC 80 _ mplementing BGP on Cisco 10S XR Software Additional References W RFCs Title RFC 3065 Autonomous System Confederations for BGP RFC 3392 Capabilities Advertisement
299. ommit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RPO CPU0 router configure Step2 router bgp autonomous system number Enters BGP configuration mode allowing you to configure the BGP routing process Example RP 0 RPO CPU0 router config router bgp 120 Step3 neighbor ip address Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Step4 remote as autonomous system number Creates a neighbor and assigns it a remote autonomous system number of 2002 Example RP 0 RPO CPU0 router config bgp nbr remote as 2002 Cisco IOS XR Routing Configuration Guide RC 38 _ mplementing BGP on Cisco 10S XR Software How to Implement BGP on Cisco IOS XR Software Hl Command or Action Purpose Step5 address family ipv4 unicast ipv4 multicast Enters neighbor address family configuration mode for the ipv6 unicast ipv6 multicast IPv4 address family Example RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Step6 weight weight value Assigns a weight of 41150 to all IPv4 unicast routes learned through 172 168 40 24 Example RP 0 RPO CPU0 router config bgp nbr af weight 41150 Step7 end Saves configuration changes or e When you issue the end command t
300. omous system 3 When the route to network A reappears autonomous system 1 sends an advertisement message to autonomous system 2 which sends it to autonomous system 3 If the route to network A repeatedly becomes unavailable then available many withdrawal and advertisement messages are sent Route flapping is a problem in an internetwork connected to the Internet because a route flap in the Internet backbone usually involves many routes Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software W Information About Implementing BGP on Cisco 10S XR Software Note No penalty is applied to a BGP peer reset when route dampening is enabled Although the reset withdraws the route no penalty is applied in this instance even if route flap dampening is enabled Minimizing Flapping The route dampening feature minimizes the flapping problem as follows Suppose again that the route to network A flaps The router in autonomous system 2 in which route dampening is enabled assigns network A a penalty of 1000 and moves it to history state The router in autonomous system 2 continues to advertise the status of the route to neighbors The penalties are cumulative When the route flaps so often that the penalty exceeds a configurable suppression limit the router stops advertising the route to network A regardless of how many times it flaps Thus the route is dampened The penalty placed on network A is decaye
301. on authentication message digest null Example RP 0 RPO CPU0 router config ospf ar authentication Enables Type 1 plain text authentication that provides no security e The example specifies plain text authentication by not specifying a keyword Use the authentication key interface command to specify the plain text password interface type instance Example RP 0 RPO CPU0 router config ospf ar interface POS 0 1 0 0 Enters interface configuration mode and associates one or more interfaces to the nonbackbone area specified in Step 7 e All interfaces configured inherit the authentication parameter values configured for area 1 Repeat Step 12 for each interface that must communicate using the same authentication interface type instance Example RP 0 RPO CPU0 router config ospf ar interface POS 0 3 0 0 Enters interface configuration mode and associates one or more interfaces to a different authentication type Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco 10S XR Software Command or Action Purpose Step 15 authentication message digest null Specifies no authentication on POS interface 0 3 0 0 overriding the plain text authentication specified for area 1 Example e By default all of the interfaces configured in the same RP 0 RPO CPUO router config ospf ar if area inherit t
302. on and operation of OSPF amp Note To execute OSPFv3 commands for this task replace ospf with ospfv3 in Steps 1 through 7 SUMMARY STEPS 1 show ospf process name 2 show ospf process name border routers router id 3 show ospf process name database 4 show ospf process name area id flood list interface type instance 5 show ospf process name area id neighbor interface type interface instance neighbor id detail 6 clear ospf process name process 7 clear ospf process name statistics neighbor interface type interface instance ip address DETAILED STEPS Command or Action Purpose Step1 show ospf process name Optional Displays general information about OSPF routing processes Example RP 0 RPO CPU0 router show ospf group1 Step2 show ospf process name border routers Optional Displays the internal OSPF routing table entries lrout r id to an ABR and ASBR Example RP 0 RP0 CPU0 router show ospf group1 border routers Cisco 10S XR Routing Configuration Guide RC 180 l _ mplementing OSPF on Cisco 10S XR Software Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose Step 3 show ospf process name database Example RP 0 RPO CPU0O router show ospf group2 database Optional Displays the lists of information related to the OSPF database for a specific router e The various forms of this command deliver information about different OSPF L
303. on changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Resetting eBGP Session Immediately Upon Link Failure Immediately resetting BGP sessions of any directly adjacent external peers if the link used to reach them goes down is enabled by default Use the bgp fast external fallover disable command to disable automatic resetting The bgp fast external fallover disable command can also be used to turn the automatic reset back on Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software Logging Neighbor Changes Logging neighbor changes is enabled by default Use the log neighbor changes disable command to turn off logging The log neighbor changes disable command can also be used to turn logging back on if it has been disabled Adjusting BGP Timers Perform this task to set the timers for BGP neighbors BGP uses certain timers to control periodic activities such as the sending of keepalive me
304. on group level define address family independent commands the same commands as in the neighbor submode e Commands entered at the address family group level define address family dependent commands for a specified address family the same commands as in the neighbor address family configuration submode e Commands entered at the neighbor group level define address family independent commands and address family dependent commands for each address family the same as all available neighbor commands and define the use command for the address family group and session group commands Template Inheritance Rules In Cisco IOS XR software BGP neighbors or groups inherit configuration from other configuration groups For address family independent configurations e Neighbors can inherit from session groups and neighbor groups e Neighbor groups can inherit from session groups and other neighbor groups e Session groups can inherit from other session groups e Ifa neighbor uses a session group and a neighbor group the configurations in the session group are preferred over the global address family configurations in the neighbor group For address family dependent configurations e Address family groups can inherit from other address family groups e Neighbor groups can inherit from address family groups and other neighbor groups e Neighbors can inherit from address family groups and neighbor groups Configuration group inheritance rules are numbere
305. on of the NET must match exactly for all of the configured items is type level 1 level 1 2 level 2 only Example RP 0 RPO CPU0 router config isis is type level 2 only Optional Configures the system type area or backbone router e By default every IS IS instance acts as a level 1 2 router e The level 1 keyword configures the software to perform Level 1 intra area routing only Only Level 1 adjacencies are established The software learns about destinations inside its area only Any packets containing destinations outside the area are sent to the nearest level 1 2 router in the area e The level 2 only keyword configures the software to perform Level 2 backbone routing only and the router establishes only Level 2 adjacencies either with other Level 2 only routers or with level 1 2 routers e The level 1 2 keyword configures the software to perform both Level 1 and Level 2 routing Both Level 1 and Level 2 adjacencies are established The router acts as a border router between the Level 2 backbone and its Level area Cisco 10S XR Routing Configuration Guide _ Implementing IS IS on Cisco 10S XR Software How to Implement IS IS on Cisco IOS XR Software Hl Command or Action Purpose Step5 enad Saves configuration changes or e When you issue the end command the system prompts commie you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel
306. on session show ospf process name area id virtual links or show ospfv3 process name virtual links Example RP 0 RPO CPUO router show ospf 1 2 virtual links or RP 0 RPO CPU0 router show ospfv3 1 virtual links Optional Displays the parameters and the current state of OSPF virtual links Cisco 10S XR Routing Configuration Guide Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software Examples In the following example the show ospfv3 virtual links EXEC command verifies that the OSPF_VLO virtual link to the OSPFv3 neighbor is up the ID of the virtual link interface is 2 and the IPv6 address of the virtual link endpoint is 2003 3000 1 RP O0 RPO CPU0 router show ospfv3 virtual links Virtual Links for OSPFv3 1 Virtual Link OSPF_VLO to router 10 0 0 3 is up Interface ID 2 IPv6 address 2003 3000 1 Run as demand circuit DoNotAge LSA allowed Transit area 0 1 20 255 via interface POS 0 1 0 1 Cost of using 2 Transmit Delay is 5 sec State POINT_TO_POINT Timer intervals configured Hello 10 Dead 40 Wait 40 Retransmit 5 Hello due in 00 00 02 Adjacency State FULL Hello suppressed Index 0 2 3 retransmission queue length 0 number of retransmission 1 First 0 0 0 0 0 0 Next 0 0 0 0 0 0 Last retransmission scan length is 1 maximum is 1 Last retransmission scan time is 0 msec maximum is 0 msec Check for lines Virtual Link OSPF_VLO
307. onditions from simple conditions by means of Boolean operators Three Boolean operators exist negation not conjunction and and disjunction or In the policy language negation has the highest precedence followed by conjunction and then by disjunction Parentheses may be used to group compound conditions to override precedence or to improve readability The following simple condition med eq 42 is true only if the value of the MED in the route is 42 otherwise it is false A simple condition may also be negated using the not operator not next hop in 10 0 2 2 Any Boolean condition enclosed in parentheses is itself a Boolean condition destination in prefix list 1 A compound condition takes either of two forms It can be a simple expression followed by the and operator itself followed by a simple condition med eq 42 and next hop in 10 0 2 2 A compound condition may also be a simpler expression followed by the or operator and then another simple condition origin is igp or origin is incomplete An entire compound condition may be enclosed in parentheses med eq 42 and next hop in 10 0 2 2 The parentheses may serve to make the grouping of subconditions more readable or they may force the evaluation of a subcondition as a unit In the following example the highest precedence not operator applies only to the destination test the and operator combines the result of the not expression with the community test an
308. onents OSPF Domain BGP autonomous system 109 Area 0 backbone E S Ss a Area 2 stub area Ss BS a OSPF Domain BGP autonomous system 65200 88721 Autonomous Systems The autonomous system is a collection of networks under the same administrative control that share routing information with each other An autonomous system is also referred to as a routing domain Figure 6 shows two autonomous systems A and B An autonomous system can consist of one or more OSPF areas Cisco 10S XR Routing Configuration Guide RC 132 _ mplementing OSPF on Cisco 10S XR Software Areas Backbone Area Stub Area Information About Implementing OSPF on Cisco 10S XR Software W Areas allow the subdivision of an autonomous system into smaller more manageable networks or sets of adjacent networks As shown in Figure 6 autonomous system A consists of three areas Area 0 Area 1 and Area 2 OSPF hides the topology of an area from the rest of the autonomous system The network topology for an area is visible only to routers inside that area When OSPF routing is within an area it is called intra area routing This routing limits the amount of link state information flood into the network reducing routing traffic It also reduces the size of the topology information in each router conserving processing and memory requirements in each router Also the routers
309. onfig isis if lsp interval 100 Step11 csnp interval seconds level 1 2 Optional Configures the interval at which periodic CSNP Example RP 0 RPO CPU0 router config isis if csnp interval 30 level 1 packets are sent on broadcast interfaces e Sending more frequent CSNPs means that adjacent routers must work harder to receive them e Sending less frequent CSNP means that differences in the adjacent routers may persist longer Step12 retransmit interval seconds level 1 2 Example RP 0 RPO CPU0 router config isis if retransmit interval 60 Optional Configures the amount of time that the sending router waits for an acknowledgment before it considers that the LSP was not received and subsequently resends Step 13 retransmit throttle interval milliseconds level 1 2 Example RP 0 RPO CPU0 router config isis if retransmit throttle interval 1000 Optional Configures the amount of time between retransmissions on each LSP on a point to point interface e This time is usually greater than or equal to the Isp interval command time because the reason for lost LSPs may be that a neighboring router is busy A longer interval gives the neighbor more time to receive transmissions Step14 mesh group number blocked Example RP 0 RPO CPU0 router config isis if mesh group blocked Optional Optimizes LSP flooding in NBMA networks with highly meshed point to point topologies
310. onfiguration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Creating a Virtual Link with MD5 Authentication to Area 0 for OSPF This task explains how to create a virtual link to your backbone area 0 and apply MD5 authentication You must perform the steps described on both ABRs one at each end of the virtual link To understand virtual links see the Virtual Link and Transit Area for OSPF section on page RC 138 Note After you explicitly configure area parameter values they are inherited by all interfaces bound to that area unless you override the values and configure them explicitly for the interface An example is provided in the Virtual Link Configured with MD5 Authentication for OSPF Version 2 Example section on page RC 192 Prerequisites Meet the following prerequisites before you create a virtual link with MD5 authentication to area 0 e Have the router ID of the neighbor router at the opposite end of the link to configure the local router You can use the show ospf or show ospfv3 command on the remote end to get its router ID Hl Cisco IOS XR Routing Configuration Guide _ mplementing OSPF on Cisco 10S XR Software S How to Implement OSPF on Cisco 10S XR Software W For a virtual link to be successful you need a stable router ID at each end o
311. onfigure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process neighbor group name Example RP 0 RPO CPU0 router config bgp neighbor group nbr grp A Places the router in neighbor group configuration mode remote as autonomous system number Example RP 0 RPO CPU0 router config bgp nbrgrp remote as 2002 Creates a neighbor and assigns it a remote autonomous system number of 2002 advertisement interval seconds Example RP 0 RPO CPU0 router config bgp nbrgrp advertisement interval 10 Optional Sets the minimum time between sending BGP routing updates to 10 seconds description text Example RP 0 RPO CPU0 router config bgp nbrgrp description Neighbor on BGP 120 Optional Configures the description Neighbor on BGP 120 for neighbor group nbr grp A dmz link bandwidth Example RP 0 RPO CPU0 router config bgp nbrgrp dmz link bandwidth Optional Advertises the bandwidth of links on router bgp 120 ebgp multihop ttl value Example RP 0 RPO CPU0 router config bgp nbrgrp ebgp multihop Optional Allows a BGP connection to neighbor group nbr grp A local as autonomous system number Example RP 0 RPO CPU0 router config bgp nbrgrp local as 30 Optional Specifies that BGP use
312. or can recognize updates from route reflectors in the same cluster All route reflectors serving a cluster should be fully meshed and all of them should have identical sets of client and nonclient peers By default the clients of a route reflector are not required to be fully meshed and the routes from a client are reflected to other clients However if the clients are fully meshed the route reflector need not reflect routes to clients As the iBGP learned routes are reflected routing information may loop The route reflector model has the following mechanisms to avoid routing loops e Originator ID is an optional nontransitive BGP attribute It is a 4 byte attributed created by a route reflector The attribute carries the router ID of the originator of the route in the local autonomous system Therefore if a misconfiguration causes routing information to come back to the originator the information is ignored e Cluster list is an optional nontransitive BGP attribute It is a sequence of cluster IDs that the route has passed When a route reflector reflects a route from its clients to nonclient peers and vice versa it appends the local cluster ID to the cluster list If the cluster list is empty a new cluster list is created Using this attribute a route reflector can identify if routing information is looped back to the same cluster due to misconfiguration If the local cluster ID is found in the cluster list the advertisement is ignored
313. or nonbackbone area and then assign one or more interfaces on which OSPF runs Prerequisites Although you can configure OSPF before you configure an IP address no OSPF routing occurs until at least one IP address is configured SUMMARY STEPS 1 configure 2 router ospf process name or router ospfv3 process name router id ipv4 address interface type interface instance area area id interface type instance Repeat Step 5 for each interface that use OSPF log adjacency changes detail enable disable o Nn eo oo FP pW end or commit Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco IOS XR Software HT How to Implement OSPF on Cisco IOS XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router ospf process name or router ospfv3 process name Example RP 0 RPO CPU0 router config router ospf 1 or RP 0 RPO CPU0 router config router ospfv3 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode or Enables OSPFv3 routing for the specified routing process and places the router in router ospfv3 configuration mode Note The process name argument is any alphanumeric string no longer than 40 characters router id ipv4 address interface type int
314. or the specified routing process Example and places the router in router ospfv3 configuration mode RP 0 RPO CPU0 router config router ospf 1 r Note The process name argument is any alphanumeric string no longer than 40 characters RP 0 RP0 CPU0 router config router ospfv3 1 Cisco 10S XR Routing Configuration Guide EGH _ mplementing OSPF on Cisco 10S XR Software Step 3 Step 4 Step 5 Step 6 Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose router id ipv4 address interface type interface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IPv4 address as the router ID timers throttle spf spf start spf hold spf max wait Example RP 0 RPO CPU0 router config ospf timers throttle spf 10 4800 90000 Sets SPF throttling timers area area id Example RP 0 RPO CPU0 router config ospf area 0 Enters area configuration mode and configures a backbone area e The area id argument can be entered in dotted decimal or IPv4 address notation such as area 1000 or area 0 0 3 232 However you must choose one form or the other for an area We recommend using the IPv4 address notation interface type instance Example RP 0 RPO CPU0 router config ospf ar interface POS 0 1 0 3 Enters interface configuration mode and asso
315. ormation originate no summary Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software 6 stub or nssa 7 default cost cost 8 end or commit 9 Repeat this task on all other routers in the stub area or NSSA DETAILED STEPS Command or Action Purpose Step1 configure Example RP 0 RPO CPU0 router configure Enters global configuration mode Step 2 router ospf process name or router ospfv3 process name Example RP 0 RPO CPU0 router config router ospf 1 or RP 0 RPO CPU0 router config router ospfv3 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode or Enables OSPFv3 routing for the specified routing process and places the router in router ospfv3 configuration mode Note The process name argument is any alphanumeric string no longer than 40 characters Step3 router id ipv4 address interface type interface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IP address as the router ID Step4 area area id Example RP 0 RPO CPU0 router config ospf area 1 Enters area configuration mode and configures a nonbackbone area for the OSPF process e The area id argument can be entered in dotted decimal or IPv4 address
316. ose AS path ends with either the autonomous system AS number 42 or 127 To remove the named AS path set use the no as path set aset1 command line interface CLD command Inline Set Form The inline set form is a parenthesized list of comma separated expressions as follows ios regex _425 ios regex _127 Implementing Routing Policy on Cisco IOS XR Software community set extcommunity set Information About Implementing Routing Policy Hi This set matches the same AS paths as the previously named set but does not require the extra effort of creating a named set separate from the policy that uses it A community set holds community values for matching against the BGP community attribute A community is a 32 bit quantity Integer community values must be split in half and expressed as two unsigned decimal integers in the range from 0 to 65535 separated by a colon Single 32 bit community values are not allowed The following is the named set form Named Set Form community set cset1 12 34 12 56 12 78 internet end set Inline Set Form 12 34 12 56 12 78 as 34 Sas tagl 12 78 internet The inline form of a community set also supports parameterization Each 16 bit portion of the community may be parameterized See the Parameterization section on page RC 214 for more information RPL provides symbolic names for the standard well known community values internet is 0 0 no export is 65535 65281
317. outes for the given address family The range is from 1 to 128000 e This example sets the maximum number of static IPv4 routes to 10000 end or commit Example RP 0 RPO CPU0 router config end or RP 0 RPO CPU0 router config commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel1 cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco IOS XR Routing Configuration Guide _ mplementing Static Routes on Cisco 10S XR Software Configuration Examples W Configuration Examples This section provides the following configuration examples e Configuring Traffic Discard Example e Configuring a Fixed Default Route Example e Configuring a Floating Static Route Example Configuring Traffic Discard Example Configuring a static route to point at interface null 0 may b
318. outes with specific AS numbers in the path The following example shows the policy definition in three parts First the as path set command defines three regular expressions to match against an AS path Second the route policy command applies the AS path set to a route If the AS path attribute of the route matches the regular expression defined with the as path set command the protocol refuses the route Third the route policy is attached to BGP neighbor 10 0 1 2 BGP consults the policy named ignore_path_as on routes received imported from neighbor 10 0 1 2 as path set ignore_path ios regex _11_ ios regex _22_ ios regex _33_ end set route policy ignore_path_as if as path in ignore_path then drop else pass endif end policy router bgp 2 neighbor 10 0 1 2 address family ipv4 unicast policy ignore_path_as in Set community based on MED The following example shows how the policy tests the MED of a route and modifies the community attribute of the route based on the value of the MED If the MED value is 127 the policy adds the community 123 456 to the route If the MED value is 63 the policy adds the value 123 789 to the community attribute of the route Otherwise the policy removes the community 123 123 from the route In any case the policy instructs the protocol to accept the route route policy quickstart med if med eq 127 then set community 123 456 additive elseif med eq 63 then set community 123 789 additive
319. outing Policy on Cisco IOS XR Software Information About Implementing Routing Policy Hi RP 0 RPO CPU0 router show bgp policy route policy test2 10 0 0 0 8 is advertised to 10 0 101 2 Path info neighbor 10 0 1 2 neighbor router id 10 0 1 2 valid external best Attributes after inbound policy was applied next hop 10 0 1 2 MET ORG AS origin incomplete neighbor as 3 metric 10 aspath 3 Attributes after outbound policy was applied next hop 10 0 1 2 MET ORG AS origin incomplete neighbor as 3 metric 333 aspath 2 3 Table Policy The table policy attach point allows the user to configure traffic index values on routes as they are installed into the global routing table This attach point supports the BGP policy accounting feature BGP policy accounting uses the traffic indexes that are set on the BGP routes to track various counters This way router operators can select different sets of BGP route attributes using the matching operations and then set different traffic indexes for each different class of route they are interested in tracking The following example shows how to set the traffic index to 10 in IPv4 unicast routes that originated from autonomous system 10 Likewise any IPv4 unicast routes that originated from autonomous system 11 have their traffic index set to 11 when they are installed into the FIB These traffic indexes are then used to count traffic being forwarded on these routes in line cards by enabling the BGP policy
320. outing policy configuration to reduce system resources required to store and process these configurations and to simplify troubleshooting Note Contents For more information about routing policy on the Cisco IOS XR software and complete descriptions of the routing policy commands listed in this module see the Related Documents section of this module To locate documentation for other commands that might appear during execution of a configuration task search online in the Cisco IOS XR software master command index Feature History for Implementing Routing Policy on Cisco 10S XR Software Release Modification Release 2 0 This feature was introduced on the Cisco CRS 1 Release 3 0 No modification Release 3 2 Support was added for the Cisco XR 12000 Series Router e Prerequisites for Implementing Routing Policy page RC 206 e Information About Implementing Routing Policy page RC 206 e How to Implement Routing Policy page RC 237 e Configuration Examples for Implementing Routing Policy page RC 241 e Additional References page RC 244 Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HZ Prerequisites for Implementing Routing Policy Prerequisites for Implementing Routing Policy The following are prerequisites for implementing Routing Policy on Cisco IOS XR Software e To use this command you must be in a user group associated with a task group tha
321. p neighbor group TIMER config bgp nbrgrp timers 10 30 config bgp nbrgrp address family ipv4 unicast config bgp nbrgrp route policy POLICY_1 in config bgp nbrgrp exit config bgp exit config bgp neighbor 192 168 2 2 config bgp nbr remote as 1 config bgp nbr use session group ADV config bgp nbr use neighbor group TIMER The following output from the show bgp neighbors command shows that the advertisement interval used is 15 seconds Cisco 10S XR Routing Configuration Guide Implementing BGP on Cisco IOS XR Software HZ Information About Implementing BGP on Cisco 10S XR Software RP 0 RPO CPU0 router show bgp neighbors 192 168 2 2 BGP neighbor is 192 168 2 2 remote AS 1 local AS 140 external link Remote router ID 0 0 0 0 BGP state Idle Last read 00 00 00 hold time is 180 keepalive interval is 60 seconds Received 0 messages 0 notifications 0 in queue Sent 0 messages 0 notifications 0 in queue Minimum time between advertisement runs is 15 seconds For Address Family IPv4 Unicast BGP neighbor version 0 Update group 0 1 eBGP neighbor with no inbound or outbound policy defaults to drop Route refresh request received 0 sent 0 0 accepted prefixes Prefix advertised 0 suppressed 0 withdrawn 0 maximum limit 524288 Threshold for warning message 75 Connections established 0 dropped 0 Last reset 00 02 03 due to BGP neighbor initialized External BGP neighbor not directly connected 4 Oth
322. page RC 232 e IS IS Policy Attach Points page RC 234 See the Cisco IOS XR Routing Command Reference for more information on the attributes and operations BGP Policy Attach Points Aggregation This section describes each of the BGP policy attach points and provides a summary of the BGP attributes and operators The aggregation attach point generates an aggregate route to be advertised based on the conditional presence of subcomponents of that aggregate Policies attached at this attach point are also able to set any of the valid BGP attributes on the aggregated routes For example the policy could set a community value or a MED on the aggregate that is generated The specified aggregate is generated if any routes evaluated by the named policy pass the policy More specifics of the aggregate are filtered using the suppress route keyword Any actions taken to set attributes in the route affect attributes on the aggregate In the policy language the configuration is controlled by which routes pass the policy The suppress map was used to selectively filter or suppress specific components of the aggregate when the summary only flag is not set In other words when the aggregate and more specific components are being sent some of the more specific components can be filtered using a suppress map In the policy language this is controlled by selecting the route and setting the suppress flag The attribute map allowed the user to set specific attri
323. ple RP 0 RPO CPU0 router config bgp bgp bestpath compare routerid Step8 end Saves configuration changes or e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RPO CPU0 router config bgp end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP 0 RPO CPU0 router config bgp commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Indicating BGP Backdoor Routes Perform this task to set the administrative distance on an external Border Gateway Protocol eBGP route to that of a locally sourced BGP route causing it to be less preferred than an Interior Gateway Protocol IGP route SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast 4 network ip address prefix length ip address mask backdoor 5 end or commit Cisco 10S XR Routi
324. pv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Enters neighbor address family configuration mode for the IPv4 address family Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software How to Implement BGP on Cisco IOS XR Software W Command or Action Purpose Step6 send community ebgp Specifies that the router send community attributes which Example RP 0 RPO CPU0 router config bgp nbr af send community ebgp are disabled by default for eBGP neighbors to eBGP neighbor 172 168 40 24 for IPv4 multicast routes Step7 ena Saves configuration changes or e When you issue the end command the system prompts comma t you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RPO CPU0 router config bgp nbr af end cancel or Entering yes saves configuration changes to the RP 0 RP0 CPUO router Can Ete bgp nbr af i commit running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to
325. pv6 unicast all all unicast multicast all flap statistics route policy route policy name Example RP 0 RPO CPU0 router config show bgp flap statistics route policy policy_A Displays BGP flap statistics for route policy policy_A show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics ip address mask prefix length Example RP 0 RPO CPU0 router show bgp flap statistics 172 20 1 1 Displays BGP flap statistics for neighbor 172 20 1 1 show bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics ip address mask prefix length longer prefixes Example RP 0 RPO CPU0 router show bgp flap statistics 172 20 1 1 longer prefixes Displays BGP flap statistics for more specific entries for neighbor 172 20 1 1 clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast all flap statistics Example RP 0 RPO CPU0 router clear bgp all all flap statistics Clears BGP flap statistics for all routes Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Step 12 Step 13 Step 14 Step 15 Step 16 Step 17 Command or Action How to Implement BGP on Cisco IOS XR Software W Purpose clear bgp ipv4 unicast multicast all ipv6 unicast all all unicast multicast
326. r Implementing BGP on Cisco 10S XR Software BGP Neighbor Configuration Example The following example shows how BGP neighbors on an autonomous system are configured to share information In the example a BGP router is assigned to autonomous system 109 and two networks are listed as originating in the autonomous system Then the addresses of three remote routers and their autonomous systems are listed The router being configured shares information about networks 131 108 0 0 and 192 31 7 0 with the neighbor routers The first router listed is in a different autonomous system the second neighbor and remote as commands specify an internal neighbor with the same autonomous system number at address 131 108 234 2 and the third neighbor and remote as commands specify a neighbor on a different autonomous system router bgp 109 network 131 108 0 0 network 192 31 7 0 neighbor 131 108 200 1 remote as 167 neighbor 131 108 234 2 remote as 109 neighbor 150 136 64 19 remote as 99 BGP Confederation Example The following is a sample configuration that shows several peers in a confederation The confederation consists of three internal autonomous systems with autonomous system numbers 6001 6002 and 6003 To the BGP speakers outside the confederation the confederation looks like a normal autonomous system with autonomous system number 666 specified using the bgp confederation identifier command In a BGP speaker in autonomous system 6001 th
327. r isis instance id net network entity title is type level 1 level 1 2 level 2 only end or commit show isis instance instance id protocol Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Command or Action Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enables IS IS routing for the specified routing instance and places the router in router configuration mode e By default all IS IS instances are automatically Level 1 and Level 2 You can change the level of routing to be performed by a particular routing instance using the is type router configuration command net network entity title Example RP 0 RPO CPU0 router config isis net 47 0004 004d 0001 0001 0c11 1110 00 Configures network entity titles NETs for the routing instance e Specify a NET for each routing instance if you are configuring multi instance IS IS You can specify a name for a NET and for an address e This example configures a router with area ID 47 0004 004d 0001 and system ID 0001 0c11 1110 00 e To specify more than one area address specify additional NETs Although the area address portion of the NET differs the systemID porti
328. r routing domain e This command causes the router to become an ASBR Example are RP 0 RPO CPU0 router config ospf redistribute by definition bgp t leyel t e OSPF tags all routes learned through redistribution as or external RP 0 RP0 CPU0 router config router Seal atribet a bop L Teval 1 3 metricctype e The protocol and its process ID if it has one indicate the protocol being redistributed into OSPF e The metric is the cost you assign to the external route The default is 20 for all protocols except BGP whose default metric is 1 e The OSPF example redistributes BGP autonomous system 1 Level 1 routes into OSPF as Type 2 external routes e The OSPFv3 example redistributes BGP autonomous system 1 Level 1 and 2 routes into OSPF The external link type associated with the default route advertised into the OSPFv3 routing domain is the Type 1 external route Note RPL is not supported for OSPFv3 Cisco 10S XR Routing Configuration Guide RC 168 l _Implementing OSPF on Cisco 10S XR Software Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose Step 5 summary prefix address mask not advertise tag tag or summary prefix ipv6 prefix prefix length not advertise tag tag Example RP 0 RPO CPU0 router config ospf summary prefix 10 1 0 0 255 255 0 0 or RP 0 RPO CPU0 router config router summary prefix 2010 11 22 32 Optional Creates a
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330. ration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Redistributing Routes from One IGP into OSPF This task redistributes routes from an IGP could be a different OSPF process into OSPF Prerequisites For information about configuring routing policy see the Implementing Routing Policy on Cisco IOS XR Software module SUMMARY STEPS 1 configure 2 router ospf process name or router ospfv3 process name 3 router id ipv4 address interface type interface instance 4 redistribute protocol process id level 1 level 1 2 level 2 metric metric value metric type type value match internal external 1 2 nssa external 1 2 tag tag value route map map tag policy policy tag Cisco 10S XR Routing Configuration Guide _Implementing OSPF on Cisco 10S XR Software How to Implement OSPF on Cisco 10S XR Software W 5 summary prefix address mask not advertise tag tag or summary prefix ipv6 prefix prefix length not advertise tag tag 6 end or commit DETAILED STEPS Step 1 Step
331. rative distance of 1 A low number indicates a preferred route By default static routes are preferred to routes learned by routing protocols Therefore you can configure an administrative distance with a static route if you want the static route to be overridden by dynamic Cisco 10S XR Routing Configuration Guide RC 248 l _ mplementing Static Routes on Cisco 10S XR Software Information About Implementing Static Routes on Cisco IOS XR Software Ml routes For example you could have routes installed by the Open Shortest Path First OSPF protocol with an administrative distance of 120 To have a static route that would be overridden by an OSPF dynamic route specify an administrative distance greater than 120 Directly Connected Routes The routing table considers the static routes that point to an interface as directly connected Directly connected networks are advertised by IGP routing protocols if a corresponding interface command is contained under the router configuration stanza of that protocol In directly attached static routes only the output interface is specified The destination is assumed to be directly attached to this interface so the packet destination is used as the next hop address The following example shows how to specify that all destinations with address prefix 2001 0DB8 32 are directly reachable through interface GigabitEthernet 0 5 0 0 RP 0 RPO CPU0 router config route ipv6 unicast 2001 0DB8 32
332. rce Discovery Protocol MSDP However these routing protocols use internal data structures similar to what RIB uses and may internally refer to the data structures as a RIB For example BGP routes are stored in the BGP RIB BRIB and multicast routes computed by multicast routing protocols such as PIM and MSDP are stored in the Multicast RIB MRIB RIB processes are not responsible for the BRIB and MRIB which are handled by BGP and multicast processes respectively The table used by the line cards and RP to forward packets is called the Forwarding Information Base FIB RIB processes do not build the FIBs Instead RIB downloads the set of selected best routes to the FIB processes by the Bulk Content Downloader BCDL process onto each line card FIBs are then constructed Cisco IOS XR Routing Configuration Guide RC 196 Implementing and Monitoring RIB on Cisco 10S XR Software Information About RIB Configuration Tl RIB Administrative Distance Forwarding is done based on the longest prefix match If you are forwarding a packet destined to 10 0 2 1 you prefer 10 0 2 0 24 over 10 0 0 0 16 because the mask 24 is longer and more specific than a 16 Routes from different protocols that have the same prefix and length are chosen based on administrative distance For instance the Open Shortest Path First OSPF protocol has an administrative distance of 110 and the Intermediate System to Intermediate System IS IS pro
333. rchical CLI and CLI Inheritance RC 131 OSPF Routing Components RC 132 OSPF Process and Router ID RC 134 Supported OSPF Network Types RC 135 Route Authentication Methods for OSPF Version 2 RC 135 Neighbors and Adjacency for OSPF RC 136 Designated Router DR for OSPF RC 136 Default Route for OSPF RC 137 Link State Advertisement Types for OSPF Version 2 RC 137 Link State Advertisement Types for OSPFv3 RC 137 Virtual Link and Transit Area for OSPF RC 138 Route Redistribution for OSPF RC 139 OSPF Shortest Path First Throttling RC 139 Nonstop Forwarding for OSPF Version 2 RC 140 Load Balancing in OSPF Version 2 and OSPFv3 RC 141 Graceful Restart for OSPFv3 RC 141 Multicast Intact Feature RC 144 How to Implement OSPF on Cisco IOS XR Software RC 144 E Cisco IOS XR Routing Configuration Guide Contents W Enabling OSPF RC 145 Configuring Stub and Not so Stubby Area Types RC 147 Configuring Neighbors for Nonbroadcast Networks RC 150 Configuring Authentication at Different Hierarchical Levels for OSPF Version 2 RC 155 Controlling the Frequency that the Same LSA Is Originated or Accepted for OSPF RC 158 Creating a Virtual Link with MD5 Authentication to Area 0 for OSPF RC 160 Summarizing Subnetwork LSAs on an OSPF ABR RC 164 Redistributing Routes from One IGP into OSPF RC 166 Configuring OSPF Shortest Path First Throttling RC 170 Configuring Nonstop Forwarding for OSPF Version 2 RC 173 Configuring OSPF Version 2 for MPLS Tr
334. recognize this signal as a cue that the neighbor relationship with this router should not be reset As the NSF capable router receives signals from other routers on the network it can begin to rebuild its neighbor list After neighbor relationships are re established the NSF capable router begins to resynchronize its database with all of its NSF aware neighbors At this point the routing information is exchanged between the OSPF neighbors After this exchange is completed the NSF capable device uses the routing information to remove stale routes update the RIB and update the FIB with the new forwarding information OSPF on the router as well as the OSPF neighbors are now fully converged Note The standardized IETF version of NSF known as OSPF graceful restart RFC 3623 is also supported Load Balancing in OSPF Version 2 and OSPFv3 When a router learns multiple routes to a specific network by using multiple routing processes or routing protocols it installs the route with the lowest administrative distance in the routing table Sometimes the router must select a route from among many learned by using the same routing process with the same administrative distance In this case the router chooses the path with the lowest cost or metric to the destination Each routing process calculates its cost differently the costs may need to be manipulated to achieve load balancing OSPF performs load balancing automatically If OSPF finds
335. rigin igp then Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software Configuration Examples for Implementing Routing Policy W endif else set community 2 999 additive endif end policy router bgp 2 neighbor 10 0 1 2 address family ipv4 unicast route policy inbound tx in Modular Inbound Policy Example The following policy example shows how to build two inbound policies in 100 and in 101 for two different peers In building the specific policies for those peers the policy reuses some common blocks of policy that may be common to multiple peers It builds a few basic building blocks the policies common inbound filter bogons and set lpref prepend The filter bogons building block is a simple policy that filters all undesirable routes such as those from the RFC 1918 address space The policy set lpref prepend is a utility policy that can set the local preference and prepend the AS path according to parameterized values that are passed in The common inbound policy uses these filter bogons building blocks to build a common block of inbound policy The common inbound policy is used as a building block in the construction of in 100 and in 101 along with the set lpref prepend building block This is a simple example that illustrates the modular capabilities of the policy language prefix set bogon 10 0 0 0 8 ge 8 le 32 0 0 0 0 0 0 0 0 0 ge 27 le 32 192 168 0 0 16 ge 16 le 32
336. rmation About Implementing IS IS on Cisco 10S XR Software Hi Flood Blocking on Specific Interfaces With this technique certain interfaces are blocked from being used for flooding LSPs but the remaining interfaces operate normally for flooding This technique is simple to understand and configure but may be more difficult to maintain and more error prone than mesh groups in the long run The flooding topology that IS IS uses is fine tuned rather than restricted Restricting the topology too much blocking too many interfaces makes the network unreliable in the face of failures Restricting the topology too little blocking too few interfaces may fail to achieve the desired scalability To improve the robustness of the network in the event that all nonblocked interfaces drop use the csnp interval command in interface configuration mode to force periodic complete sequence number PDUs CSNPs packets to be used on blocked point to point links The use of periodic CSNPs enables the network to become synchronized Mesh Group Configuration Configuring mesh groups a set of interfaces on a router can help to limit flooding All routers reachable over the interfaces in a particular mesh group are assumed to be densely connected with each router having at least one link to every other router Many links can fail without isolating one or more routers from the network In normal flooding a new LSP is received on an interface and is flooded out over al
337. roup GROUP_1 inheritance Session s GROUP_2 s GROUP_3 The following is sample output from the show bgp session group command with the users keyword showing that both the GROUP_1 and GROUP_2 session groups inherit session parameters from the GROUP_3 session group RP 0 RPO CPU0 router show bgp session group GROUP_3 users Session s GROUP_1 s GROUP_2 show bgp neighbor group Use the show bgp neighbor group command to display neighbor groups e Use the configuration keyword to display the effective configuration for the neighbor group including any settings that have been inherited from neighbor groups used by this neighbor group e Use the inheritance keyword to display the address family groups session groups and neighbor groups from which this neighbor group is capable of inheriting configuration e Use the users keyword to display the neighbors and neighbor groups that inherit configuration from this neighbor group The examples are based on the following group configuration RP 0 RPO CPU0O router config router bgp 140 RP 0 RPO CPU0 router config bgp af group GROUP_3 address family ipv4 unicast RP 0 RPO CPU0 router config bgp afgrp remove private as RP 0 RPO CPU0 router config bgp afgrp soft reconfiguration inbound RP 0 RPO CPU0 router config bgp afgrp exit RP 0 RPO CPU0 router config bgp af group GROUP_2 address family ipv4 unicast RP 0 RPO CPU0 router config bgp afgrp use af group GROU
338. rovides the following output examples e Sample Output for the show ospf Command Before Configuring MPLS TE page RC 178 e Sample Output for the show ospf mpls traffic eng Command page RC 179 e Sample Output for the show ospf Command After Configuring MPLS TE page RC 180 Sample Output for the show ospf Command Before Configuring MPLS TE In the following example the show route ospf EXEC command verifies that POS interface 0 3 0 0 exists and MPLS TE is not configured RP 0 RPO CPU0 router show route ospf 1 0 O E2 192 168 10 0 24 110 20 via 192 168 1 2 00 02 50 POS 0 3 0 0 110 20 via 192 168 4 1 00 02 50 POS 0 3 0 1 O E2 192 168 11 0 24 110 20 via 192 168 1 2 00 02 50 POS 0 3 0 0 110 20 via 192 168 4 1 00 02 50 POS 0 3 0 1 O E2 192 168 244 0 24 110 20 via 192 168 1 2 00 02 50 POS 0 3 0 0 110 20 via 192 168 4 1 00 02 50 POS 0 3 0 1 O 192 168 12 0 24 110 2 via 192 168 1 2 00 02 50 POS 0 3 0 0 110 2 via 192 168 4 1 00 02 50 POS 0 3 0 1 Cisco 10S XR Routing Configuration Guide RC 178 _Implementing OSPF on Cisco 10S XR Software How to Implement OSPF on Cisco 10S XR Software W Sample Output for the show ospf mpls traffic eng Command In the following example the show ospf mpls traffic eng EXEC command verifies that the MPLS TE fragments are configured correctly RP 0 RPO CPU0 router show ospf 1 mpls traffic eng fragment OSPF Router with ID 192 168 4 3 Process ID 1 Area 0
339. rs global configuration mode Example RP 0 RPO CPU0 router configure Step2 router isis instance id Enables IS IS routing for the specified routing instance and places the router in router configuration mode Example e You can change the level of routing to be performed by RP 0 RPO CPU0 router config router isis isp a particular routing instance using the is type router configuration command Step3 nsf cisco ietf Enables NSF on the next restart e Enter the cisco keyword to run IS IS in heterogeneous Example networks that might not have adjacent NSF aware RP 0 RPO CPU0 router config isis nsf ietf networking devices e Enter the ietf keyword to enable IS IS in homogeneous networks where all adjacent networking devices support IETF draft based restartability Cisco 10S XR Routing Configuration Guide RC 106 _ Implementing IS IS on Cisco 10S XR Software Step 4 Step 5 Step 6 Step 7 Step 8 Command or Action How to Implement IS IS on Cisco IOS XR Software Hl Purpose nsf interface expires number Example RP 0 RPO CPU0 router config isis nsf interface expires 1 Configures the number of resends of an acknowledged NSF restart acknowledgment e Ifthe resend limit is reached during the NSF restart the restart falls back to a cold restart nsf interface timer seconds Example RP 0 RPO CPU0 router config isis interface timer 15 nsf Configures the number
340. s timers lsa min arrival seconds timers Isa group pacing seconds enw ef PF amp end or commit Cisco 10S XR Routing Configuration Guide RC 158 _Implementing OSPF on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router ospf process name or router ospfv3 process name Example RP 0 RPO CPU0 router config router ospf 1 or RP 0 RPO CPU0 router config router ospfv3 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode or Enables OSPFv3 routing for the specified routing process and places the router in router ospfv3 configuration mode Note The process name argument is any alphanumeric string no longer than 40 characters router id ipv4 address interface type interface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IP address as the router ID Perform Step 5 or Step 6 or both to control the frequency that the same LSA is originated or accepted timers lsa gen interval seconds Example RP 0 RPO CPU0 router config ospf timers lsa gen interval 10 Changes the minimum int
341. s added security measure ensures that routes cannot accidentally be accepted or advertised in the case of a configuration omission error Note This enforcement affects only eBGP neighbors neighbors in a different autonomous system than this router For internal BGP iBGP neighbors neighbors in the same autonomous system all routes are accepted or advertised if there is no policy In the following example for an eBGP neighbor if all routes should be accepted and advertised with no modifications a simple pass all policy is configured RP 0 RPO CPUO RP 0 RPO CPUO RP 0 RPO CPUO RP 0 RPO CPUO router router router router config route policy pass all config rpl pass config rpl end policy config commit Use the route policy BGP command in the neighbor address family configuration mode to apply the pass all policy to a neighbor The following example shows how to allow all IPv4 unicast routes to be received from neighbor 192 168 40 42 and advertise all IPv4 unicast routes back to it RP 0 RPO CPU0 router config router bgp 1 RP 0 RPO CPU0 router config bgp neighbor 192 168 40 24 RP 0 RPO CPU0 router config bgp nbr remote as 2 RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast RP 0 RPO CPU0 router config bgp nbr af route policy pass all in RP 0 RPO CPU0 router config bgp nbr af route policy pass all out RP 0 RPO CPU0 router config bgp nbr af commit Use the s
342. s adjacency log command RC 101 show isis command RC 93 show isis database command RC 105 show isis database log command RC 105 show isis interface command RC 116 show isis Isp log command RC 105 show isis mpls command RC 112 show isis mpls traffic eng adjacency log command RC 112 show isis mpls traffic eng advertisements command RC 112 show isis neighbors command RC 116 show isis spf log command RC 118 show isis topology command RC 97 show running config command RC 107 G graceful restart helper command RC 142 graceful restart interval command RC 142 graceful restart lifetime command RC 142 hello interval IS IS command RC 114 hello interval OSPF command RC 152 hello multiplier command RC 114 hello padding command RC 114 hello password command RC 110 RC 115 ignore lsp errors command RC 104 inheritance configurations BGP RC 7 monitoring RC 11 Cisco 10S XR Routing Configuration Guide E W index interior routers RC 134 IPv6 IS IS support multitopology RC 88 single topology RC 87 RIB support RC 197 routing RC 86 IS IS Intermediate System to Intermediate System adjacencies tuning RC 113 attached bit on an instance RC 90 authentication configuring RC 108 Cisco IOS and Cisco IOS XR software differences configuration grouped RC 85 configuration grouped configuration RC 85 Level 1 or Level 2 routing RC 91 multitopology RC 98 restrictions RC 84 single topology RC 93 customiz
343. s if the applied policy were cut and pasted into the applying policy route policy check as 1234 prime if as path passes through 1234 then drop else pass endif end policy You may have as many levels of hierarchy as desired However many levels may be difficult to maintain and understand Parameterization Cisco IOS XR Routing Configuration Guide In addition to supporting reuse of policies using the apply statement policies can be defined that allow for parameterization of some of the attributes The following example shows how to define a parameterized policy named param example In this case the policy takes one parameter mytag Parameters always begin with a dollar sign and consist otherwise of any alphanumeric characters Parameters can be substituted into any attribute that takes a parameter In the following example a 16 bit community tag is used as a parameter route policy param example Smytag set community 1234 mytag additive end policy This parameterized policy can then be reused with different parameterizations as shown in the following example In this manner policies that share a common structure but use different values in some of their individual statements can be modularized For details on which attributes can be parameterized see the individual attribute sections Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy i route policy origin 10
344. s into Multiprotocol BGP Perform this task to redistribute prefixes from another protocol into multiprotocol BGP Redistribution is the process of injecting prefixes from one routing protocol into another routing protocol This task shows how to inject prefixes from another routing protocol into multiprotocol BGP Specifically prefixes that are redistributed into multiprotocol BGP using the redistribute command are injected into the unicast database the multicast database or both SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast 4 redistribute connected metric metric value route policy route policy name or redistribute isis process id level 1 1 inter area 2 metric metric value route policy route policy name or redistribute ospf process id match external 1 2 internal nssa external 1 2 metric metric value route policy route policy name or redistribute ospfv3 process id match external 1 2 internal nssa external 1 2 metric metric value route policy route policy name or redistribute static metric metric value route policy route policy name 5 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Example RP 0 RPO CPU0 router configure Enters global configuration mode Step2 router bgp autonomous system number Enters BGP configuration mode allowi
345. se configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router ospf process name or router ospfv3 process name Example RP 0 RPO CPU0 router config router ospf 1 or RP 0 RPO CPU0 router config router ospfv3 1 Enables OSPF routing for the specified routing process and places the router in router configuration mode or Enables OSPFv3 routing for the specified routing process and places the router in router ospfv3 configuration mode Note The process name argument is any alphanumeric string no longer than 40 characters router id ipv4 address interface type interface instance Example RP 0 RPO CPU0 router config ospf router id 192 168 4 3 Configures a router ID for the OSPF process Note We recommend using a stable IPv4 address as the router ID area area id Example RP 0 RPO CPU0 router config ospf area 0 Enters area configuration mode and configures a nonbackbone area for the OSPF process e The area id argument can be entered in dotted decimal or IPv4 address notation such as area 1000 or area 0 0 3 232 However you must choose one form or the other for an area We recommend using the IPv4 address notation range ip address mask advertise not advertise or range ipv6 prefix prefix length advertise not advertise Example RP 0 RPO CPU0 router config ospf ar range 192 168 0 0 255 255 0 0 advertise or Example
346. se 3 2 Support was added for the Cisco XR 12000 Series Router e Prerequisites for Implementing BGP on Cisco IOS XR Software page RC 2 e Information About Implementing BGP on Cisco IOS XR Software page RC 2 e How to Implement BGP on Cisco IOS XR Software page RC 27 e Configuration Examples for Implementing BGP on Cisco IOS XR Software page RC 76 e Where to Go Next page RC 79 e Additional References page RC 80 Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software W Prerequisites for Implementing BGP on Cisco 10S XR Software Prerequisites for Implementing BGP on Cisco IOS XR Software To use this command you must be in a user group associated with a task group that includes the proper task IDs For detailed information about user groups and task IDs see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide Information About Implementing BGP on Cisco IOS XR Software To implement BGP you need to understand the following concepts e BGP Functional Overview page RC 2 e BGP Router Identifier page RC 3 e BGP Default Limits page RC 3 e BGP Validation of Local Next Hop Addresses page RC 4 e BGP Configuration page RC 4 e No Default Address Family page RC 15 e Routing Policy Enforcement page RC 16 e Update Groups page RC 18 e BGP Best Path Algorithm page RC 18 e Multiprotocol BGP page RC 21 e Route Dampening page RC 23
347. set med 8 if community matches any cs1 then set local preference 122 if community matches any cs2 then set med 12 endif endif The result is a route with a MED of 8 unless the community list of the route matches both cs1 and cs2 in which case the result is a route with a MED of 12 In the case in which the attribute being modified can contain only one value it is easy to think of this case as the last statement wins However a few attributes can contain multiple values and the result of multiple actions on the attribute is cumulative rather than as a replacement The first of these cases is the use of the additive keyword on community and extended community evaluation Consider a policy of the form route policy community add set community 10 23 set community 10 24 additive set community 10 25 additive end policy This policy sets the community string on the route to contain all three community values 10 23 10 24 and 10 25 The second of these cases is AS path prepending Consider a policy of the form route policy prepend example prepend as path 2 3 prepend as path 666 2 end policy This policy prepends the following to the AS path 666 666 2 2 2 This prepending is a result of all actions being taken and to AS path being an attribute that contains an array of values rather than a simple scalar value When Attributes Are Modified A policy does not modify route attribute values until all tests have been completed I
348. sit Area for OSPF page RC 138 Route Redistribution for OSPF page RC 139 OSPF Shortest Path First Throttling page RC 139 Cisco 10S XR Routing Configuration Guide RC 128 _ mplementing OSPF on Cisco 10S XR Software Information About Implementing OSPF on Cisco 10S XR Software W e Nonstop Forwarding for OSPF Version 2 page RC 140 e Load Balancing in OSPF Version 2 and OSPFv3 page RC 141 OSPF Functional Overview OSPF is a routing protocol for IP It is a link state protocol as opposed to a distance vector protocol A link state protocol makes its routing decisions based on the states of the links that connect source and destination machines The state of the link is a description of that interface and its relationship to its neighboring networking devices The interface information includes the IP address of the interface network mask type of network to which it is connected routers connected to that network and so on This information is propagated in various types of link state advertisements LSAs A router stores the collection of received link state advertisement LSA data in a link state database This database includes LSA data for the links of the router The contents of the database when subjected to the Dijkstra algorithm extract data to create an OSPF routing table The difference between the database and the routing table is that the database contains a complete collection of raw data the routing table cont
349. sk The default route is expressed as a prefix with length 0 e Interarea router LSA for ASBRs Type 4 Advertises an ASBR and the cost to reach it Routers that are trying to reach an external network use these advertisements to determine the best path to the next hop ABRs generate Type 4 LSAs e Autonomous system external LSA Type 5 Redistributes routes from another autonomous system usually from a different routing protocol into OSPF In OSPFVv3 addresses for these LSAs are expressed as prefix and prefix length instead of address and mask The default route is expressed as a prefix with length 0 e Link LSA Type 8 Has link local flooding scope and is never flooded beyond the link with which it is associated Link LSAs provide the link local address of the router to all other routers attached to the link or network segment inform other routers attached to the link of a list of IPv6 prefixes to associate with the link and allow the router to assert a collection of Options bits to associate with the network LSA that is originated for the link e Intra area prefix LSAs Type 9 A router can originate multiple intra area prefix LSAs for every router or transit network each with a unique link state ID The link state ID for each intra area prefix LSA describes its association to either the router LSA or network LSA and contains prefixes for stub and transit networks An address prefix occurs in almost all newly defined
350. ssages and the interval after which a neighbor is assumed to be down if no messages are received from the neighbor during the interval The values set using the timers bgp command can be overridden on particular neighbors using the timers command in the neighbor configuration mode SUMMARY STEPS 1 configure 2 router bgp autonomous system number 3 timers bgp keepalive hold time 4 neighbor ip address 5 timers keepalive hold time 6 end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP O0 RPO CPU0 router configure Step2 router bgp autonomous system number Enters BGP configuration mode allowing you to configure the BGP routing process Example RP 0 RPO CPU0 router config router bgp 120 Step3 timers bgp keepalive hold time Sets a default keepalive time of 30 seconds and a default hold time of 90 seconds for all neighbors Example RP 0 RPO CPU0 router config bgp timers bgp 30 90 Cisco IOS XR Routing Configuration Guide RC 34 _ mplementing BGP on Cisco 10S XR Software Step 4 Step 5 Step 6 How to Implement BGP on Cisco IOS XR Software Hl Command or Action Purpose neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer timers keepalive hold time
351. summary performance statistics DETAILED STEPS Step 1 Command or Action Purpose show bgp ipv4 ipv all unicast multicast all update group neighbor ip address process id index summary performance statistics Example RP 0 RPO CPU0 router show bgp update group 0 0 Displays information about BGP update groups The ip address argument displays the update groups to which that neighbor belongs The process id index argument selects a particular update group to display and is specified as follows process id dot index Process ID range is from 0 to 254 Index range is from 0 to 4294967295 The summary keyword displays summary information for neighbors in a particular update group If no argument is specified this command displays information for all update groups for the specified address family The performance statistics keyword displays performance statistics for an update group Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software WE Configuration Examples for Implementing BGP on Cisco 10S XR Software Configuration Examples for Implementing BGP on Cisco IOS XR Software This section provides the following configuration examples e Enabling BGP Example page RC 76 e Displaying BGP Update Groups Example page RC 77 e BGP Neighbor Configuration Example page RC 78 e BGP Confederation Example page RC 78 e BGP Route Reflector Example
352. systemid system id 11 show isis adjacency log 12 show isis instance instance id interface type instance brief detail level 1 2 13 show isis instance instance id neighbors interface type interface instance summary detail systemid system id Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HT How to Implement IS IS on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Command or Action Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router isis instance id Example RP 0 RPO CPU0 router config router isis isp Enables IS IS routing for the specified routing instance and places the router in router configuration mode e You can change the level of routing to be performed by a particular routing instance using the is type command log adjacency changes Example RP 0 RPO CPU0 router config isis log adjacency changes Generates a log message when an IS IS adjacency changes state up or down interface type number Example RP 0 RPO CPU0 router config isis interface POS 0 1 0 3 Enters interface configuration mode hello padding disable sometimes 2 level 1 Example RP 0 RP0 CPU0 router config isis if hello paddi ng sometimes Configures padding on IS IS hello PDUs for all IS IS interfaces on
353. t all dampening ip address mask length Cisco IOS XR Routing Configuration Guide RC 48 l _ mplementing BGP on Cisco 10S XR Software DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 How to Implement BGP on Cisco IOS XR Software Hi Command or Action Purpose configure Example RP 0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp address family ipv4 unicast Enters global address family configuration mode for the IPv4 address family bgp dampening max suppress time half life reuse suppress route policy route policy name Example RP 0 RPO CPUO router config bgp af bgp dampening 30 1500 10000 120 Configures BGP dampening for the IPv4 address family The half life argument is set to 30 the reuse argument is set to 1500 the suppress argument is set to 10000 and the max suppress time argument is set to 120 end or commit Example RP 0 RPO CPU0 router config bgp af end or RP 0 RPO CPU0 router config bgp af commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Un
354. t each authenticated by the old key and new key The software tracks which devices start using the new key and the software stops sending duplicate packets after it detects that all of its neighbors are using the new key The software then discards the old key The network administrator must then remove the old key from each the configuration file of each router Neighbors and Adjacency for OSPF Routers that share a segment Layer 2 link between two interfaces become neighbors on that segment OSPF uses the hello protocol as a neighbor discovery and keep alive mechanism The hello protocol involves receiving and periodically sending hello packets out each interface The hello packets list all known OSPF neighbors on the interface Routers become neighbors when they see themselves listed in the hello packet of the neighbor After two routers are neighbors they may proceed to exchange and synchronize their databases which creates an adjacency On broadcast and NBMA networks all neighboring routers have an adjacency Designated Router DR for OSPF On point to point and point to multipoint networks the Cisco IOS XR software floods routing updates to immediate neighbors No DR or backup DR BDR exists all routing information is flooded to each router On broadcast or NBMA segments only OSPF minimizes the amount of information being exchanged on a segment by choosing one router to be a DR and one router to be a BDR Thus the routers on the se
355. t element entry gt is an entry of an item appropriate to the type of usage such as a prefix or a community value The following is an example using an inline community set route policy sample inline if community matches any 10 15 100 then set local preference 100 endif end policy The following is an equivalent example using the named set test communities community set test communities 10 100 11 100 12 100 13 100 14 100 15 100 end set route policy sample if community matches any test communities then set local preference 100 endif end policy Both of these policies are functionally equivalent but the inline form does not require the configuration of the community set just to store the six values You can choose the form appropriate to the configuration context In the following sections examples of both the named set version and the inline form are provided where appropriate An AS path set comprises operations for matching an AS path attribute The only matching operation is a regular expression match Named Set Form The named set form uses the ios regex keyword to indicate the type of regular expression and requires single quotation marks around the regular expression The following is a sample definition of a named AS path set as path set asetl ios regex _42 ios regex _127 end set This AS path set comprises two elements When used in a matching operation this AS path set matches any route wh
356. t from the show bgp neighbor group command with the users keyword This output shows that the GROUP_1 neighbor group inherits session address family independent configuration parameters from the GROUP_2 neighbor group The GROUP_1 neighbor group also inherits IPv4 unicast configuration parameters from the GROUP_2 neighbor group RP 0 RPO CPU0 router show bgp neighbor group GROUP_2 users Session n GROUP_1 IPv4 Unicast n GROUP_1 No Default Address Family BGP does not support the concept of a default address family An address family must be explicitly configured under the BGP router configuration for the address family to be activated in BGP Similarly an address family must be explicitly configured under a neighbor for the BGP session to be activated under that address family It is not required to have any address family configured under the BGP router configuration level for a neighbor to be configured However it is a requirement to have an address family configured at the BGP router configuration level for the address family to be configured under a neighbor Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HZ Information About Implementing BGP on Cisco 10S XR Software Routing Policy Enforcement External BGP eBGP neighbors must have an inbound and outbound policy configured If no policy is configured no routes are accepted from the neighbor nor are any routes advertised to it Thi
357. t in e The keyword resets all BGP neighbors e The ip address argument specifies the address of the Example neighbor to be reset RP O0 RPO CPU0 router clear bgp ipv4 unicast e The as number argument specifies that all neighbors 10 0 0 1 soft in that match the autonomous system number be reset e The external keyword specifies that all external neighbors are reset Resetting Neighbors Using BGP Outbound Soft Reset Perform this task to trigger an outbound soft reset of the specified address families for the specified group or neighbors Resetting neighbors is useful if you change the outbound policy for the neighbors or any other configuration that affects the sending or receiving of routing updates If an outbound soft reset is triggered BGP resends all routes for the address family to the given neighbors To determine whether the neighbor has advertised the ROUTE_REFRESH capability use the show bgp neighbors command Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software SUMMARY STEPS 1 show bgp neighbors 2 clear bgp ipv4 ipv6 all unicast multicast all ip address as number external soft out DETAILED STEPS Command or Action Purpose Step1 show bgp neighbors Verifies that received route refresh capability from the neighbor is enabled Example RP 0 RPO CPU0 router show bgp neighbors Step2 cle
358. t includes the proper task IDs For detailed information about user groups and task IDs see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide e Border Gateway Protocol BGP integrated Intermediate System to Intermediate System IS IS or Open Shortest Path First OSPF must be configured in your network Information About Implementing Routing Policy To implement RPL you need to understand the following concepts e Routing Policy Language page RC 206 e Routing Policy Language page RC 206 e Routing Policy Configuration Basics page RC 213 e Policy Definitions page RC 213 e Parameterization page RC 214 e Semantics of Policy Application page RC 215 e Policy Statements page RC 219 e Attach Points page RC 223 e Attached Policy Modification page RC 235 e Nonattached Policy Modification page RC 235 Routing Policy Language This section contains the following information e Routing Policy Language Overview page RC 206 e Routing Policy Language Structure page RC 207 e Routing Policy Language Components page RC 211 e Routing Policy Language Usage page RC 211 Routing Policy Language Overview RPL was developed to support large scale routing configurations RPL has several fundamental capabilities that differ from those present in configurations oriented to traditional route maps access lists and prefix lists The first of these capabilities is the ability to buil
359. t intact for OSPFv2 routes that use IPv4 addresses Summary Steps 1 configure router ospf instance id mpls traffic eng multicast intact PF w N end or commit DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RP0 CPU0 router configure Step2 router ospf instance id Enables OSPF routing for the specified routing process and Example RP 0 RP0 CPU0 router config router ospf isp places the router in router configuration mode In this example the OSPF instance is called isp Cisco 10S XR Routing Configuration Guide RC 186 _ mplementing OSPF on Cisco 10S XR Software Step 3 Step 4 Command or Action Configuration Examples for Implementing OSPF on Cisco IOS XR Software Wi Purpose mpls traffic eng multicast intact Example RP 0 RPO CPU0 router config isis mpls traffic eng multicast intact Enables multicast intact end or commit Example RP 0 RPO CPU0 router config isis af end or RP 0 RPO CPU0 router config isis af commit Saves configuration changes When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configura
360. t is installed in RIB regardless of reachability Networking devices forward packets using route information that is either manually configured or dynamically learned using a routing protocol Static routes are manually configured and define an explicit path between two networking devices Unlike a dynamic routing protocol static routes are not automatically updated and must be manually reconfigured if the network topology changes The benefits of using static routes include security and resource efficiency Static routes use less bandwidth than dynamic routing protocols and no CPU cycles are used to calculate and communicate routes The main disadvantage to using static routes is the lack of automatic reconfiguration if the network topology changes Static routes can be redistributed into dynamic routing protocols but routes generated by dynamic routing protocols cannot be redistributed into the static routing table No algorithm exists to prevent the configuration of routing loops that use static routes Static routes are useful for smaller networks with only one path to an outside network and to provide security for a larger network for certain types of traffic or links to other networks that need more control In general most networks use dynamic routing protocols to communicate between networking devices but may have one or two static routes configured for special cases Default Administrative Distance Static routes have a default administ
361. t originate maximum prefix 2500 75 warning only route policy POLICY_1 in remove private AS send community ebgp send extended community ebgp GROUP_2 GROUP_2 a GROUP_3 GROUP_2 GROUP_2 a a GROUP_2 a GROUP_3 a a a The following example displays sample output from the show bgp af group command using the users keyword RP 0 RPO CPUO router show bgp af group GROUP_2 users IPv4 Unicast a GROUP_1 The following example displays sample output from the show bgp af group command using the inheritance keyword This shows that the specified address family group GROUP_1 directly uses the GROUP_2 address family group which in turn uses the GROUP_3 address family group RP 0 RPO CPU0 router show bgp af group GROUP_1 inheritance IPv4 Unicast a GROUP_2 a GROUP_3 show bgp session group Use the show bgp session group command to display session groups e Use the configuration keyword to display the effective configuration for the session group including any settings that have been inherited from session groups used by this session group e Use the inheritance keyword to display the session groups from which this session group is capable of inheriting configuration e Use the users keyword to display the session groups neighbor groups and neighbors that inherit configuration from this session group The examples that follow sample output from the show bgp session group command with the configuration keyword in EXEC m
362. t this URL http www cisco com discuss networking World class networking training is available from Cisco You can view current offerings at this URL http www cisco com en US learning index html Cisco IOS XR Routing Configuration Guide Implementing BGP on Cisco IOS XR Software The Border Gateway Protocol BGP is an Exterior Gateway Protocol EGP that allows you to create loop free interdomain routing between autonomous systems An autonomous system is a set of routers under a single technical administration Routers in an autonomous system can use multiple Interior Gateway Protocols IGP to exchange routing information inside the autonomous system and an EGP to route packets outside the autonomous system This module describes information that is unique to BGP for IP Version 4 IPv4 and IP Version 6 IPv6 implementation in Cisco IOS XR Software Note Contents For more information about BGP on the Cisco IOS XR software and complete descriptions of the BGP commands listed in this module you can see the Related Documents section of this module To locate documentation for other commands that might appear while executing a configuration task search online in the Cisco IOS XR software master command index Feature History for Implementing BGP on Cisco IOS XR Configuration Module Release Modification Release 2 0 This feature was introduced on the Cisco CRS 1 Release 3 0 No modification Relea
363. tabase filter all Example RP 0 RPO CPU0 router config ospf ar neighbor 10 34 16 6 or RP 0 RPO CPU0 router config ospf ar neighbor fe80 3203 a0ff fe9d f3f Configures the IPv4 address of OSPF neighbors interconnecting to nonbroadcast networks or Configures the link local IPv6 address of OSPFv3 neighbors e The ipv6 link local address argument must be in the form documented in RFC 2373 in which the address is specified in hexadecimal using 16 bit values between colons e The priority keyword notifies the router that this neighbor is eligible to become a DR or BDR The priority value should match the actual priority setting on the neighbor router The neighbor priority default value is zero This keyword does not apply to point to multipoint interfaces e The poll interval keyword does not apply to point to multipoint interfaces RFC 1247 recommends that this value be much larger than the hello interval The default is 120 seconds 2 minutes e Neighbors with no specific cost configured assumes the cost of the interface based on the cost command On point to multipoint interfaces cost number is the only keyword and argument combination that works The cost keyword does not apply to NBMA networks e The database filter keyword filters outgoing LSAs to an OSPF neighbor If you specify the all keyword incoming and outgoing LSAs are filtered Use with extreme caution since filtering may cause the routing
364. tached interface of the neighbor e Unlike in OSPFv2 multiple OSPFv3 processes can be run on a link e LSAs in OSPFV3 are expressed as prefix and prefix length instead of address and mask e The router ID is a 32 bit number with no relationship to an IPv6 address Importing Addresses into OSPFv3 When importing into OSPFV3 the set of addresses configured on an OSPFV3 interface users cannot select specific addresses to be imported Either all addresses are imported or no addresses are imported OSPF Hierarchical CLI and CLI Inheritance Cisco IOS XR software introduces new OSPF configuration fundamentals consisting of hierarchical CLI and CLI inheritance Hierarchical CLI is the grouping of related network component information at defined hierarchical levels such as at the router area and interface levels Hierarchical CLI allows for easier configuration maintenance and troubleshooting of OSPF configurations When configuration commands are displayed together in their hierarchical context visual inspections are simplified Hierarchical CLI is intrinsic for CLI inheritance to be supported With CLI inheritance support you need not explicitly configure a parameter for an area or interface In Cisco IOS XR the parameters of interfaces in the same area can be exclusively configured with a single command or parameter values can be inherited from a higher hierarchical level such as from the area configuration level or the rout
365. tact feature You can enable multicast intact in the IGP when multicast routing protocols PIM are configured and IGP shortcuts are configured on the router IGP shortcuts are MPLS tunnels that are exposed to IGP The IGPs route the IP traffic over these tunnels to destinations that are downstream from the egress router of the tunnel from an SPF perspective PIM cannot use IGP shortcuts for propagating PIM joins because reverse path forwarding RPF cannot work across a unidirectional tunnel When you enable multicast intact on an IGP the IGP publishes a parallel or alternate set of equal cost next hops for use by PIM These next hops are called mcast intact next hops The mcast intact next hops have the following attributes e They are guaranteed not to contain any IGP shortcuts e They are not used for unicast routing but are used only by PIM to look up an IPv4 next hop to a PIM source e They are not published to the FIB e When multicast intact is enabled on an IGP all IPv4 destinations that were learned through link state advertisements are published with a set equal cost mcast intact next hops to the RIB This attribute applies even when the native next hops have no IGP shortcuts e InIS IS the max paths limit is applied by counting both the native and mcast intact next hops together In OSPF V2 the behavior is slightly different Cisco IOS XR Routing Configuration Guide RC 90 _Implementing IS IS on Cisco 10S XR S
366. tance_10 using the policy ISIS redist This policy sets the level to level 1 2 for all redistributed routes OSPF routes with a tag of 10 have their metric set to 100 and IS IS routes with a tag of 20 have their IS IS metric set to 200 Any IS IS routes not carrying a tag of either 10 or 20 are not be redistributed into the IS IS database route policy ISIS redist set level level 1 2 if tag eq 10 then set metric 100 elseif tag eq 20 then set metric 200 else drop endif end policy router isis instance_10 address family ipv4 unicast redistribute ospf 1 policy ISIS redist IS IS Attributes and Operators Table 7 summarizes the IS IS attributes and operators Table 7 IS IS Attributes and Operators Attribute Match Set Destination in n a Level n a set metric n a set metric type n a set rib has route in n a route type is n a tag eq ge le n a Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy Hi Attached Policy Modification amp Policies that are in use do on occasion need to be modified In the traditional configuration model a policy modification would be done by completely removing the policy and re entering it However this model allows for a window of time in which no policy is attached and default actions to be used which is an opportunity for inconsistencies to exist To close this
367. tatement neighbor 1 2 3 4 address family ipv4 unicast policy sample1 in the configuration attempt is rejected because the policy sample2 does not exist Editing Routing Policy Configuration Elements RPL is based on statements rather than on lines That is within the begin end pair that brackets policy statements from the CLI a new line is merely a separator the same as a space character The CLI provides the means to enter and delete route policy statements RPL provides a means to edit the contents of the policy between the begin end brackets using a microemacs editor Editing Routing Policy Configuration Elements Using the EMACS Editor To edit the contents of a routing policy use the following CLI command in EXEC mode edit route policy prefix set as path set community set extended community set name A copy of the route policy is copied to a temporary file and the editor is launched After editing save the changes by using the save buffer command C X C S Control X Control S To exit the editor use the quit command Control X Control C When you quit the editor the buffer is committed If there are no parse errors the configuration is committed Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software Information About Implementing Routing Policy RP O0 RPO CPU0 router edit route policy policy_A MicroEMACS 3 8b rpl_edit 139281 if destination in 2001
368. te Generation and Update Groups The BGP Update Groups feature separates BGP update generation from neighbor configuration The BGP Update Groups feature introduces an algorithm that dynamically calculates BGP update group membership based on outbound routing policies This feature does not require any configuration by the network operator Update group based message generation occurs automatically and independently BGP Update Group When a change to the configuration occurs the router automatically recalculates update group memberships and applies the changes For the best optimization of BGP update group generation we recommend that the network operator keeps outbound routing policy the same for neighbors that have similar outbound policies This feature contains commands for monitoring BGP update groups For more information about the commands see the Monitoring BGP Update Groups section on page RC 75 BGP Best Path Algorithm BGP routers typically receive multiple paths to the same destination The BGP best path algorithm determines the best path to install in the IP routing table and to use for forwarding traffic This section describes the IOS XR implementation of BGP best path algorithm as specified in Section 9 1 of the Internet Engineering Task Force IETF Network Working Group draft ietf idr bgp4 24 txt document Cisco 10S XR Routing Configuration Guide RC 18 _ mplementing BGP on Cisco 10S XR Software Infor
369. te map to identify the level into which the default route is to be announced and you can specify other filtering options configurable under a route map You can use a route map to conditionally advertise the default route depending on the existence of another route in the routing table of the router Attached Bit on an IS IS Instance A The attached bit is set in a router that is configured with the is type command and level 1 2 keyword The attached bit indicates that the router is connected to other areas typically through the backbone This functionality means that the router can be used by Level routers in the area as the default route to the backbone The attached bit is usually set automatically as the router discovers other areas while computing its Level 2 SPF route The bit is automatically cleared when the router becomes detached from the backbone To simulate this behavior when using multiple processes to represent the level 1 2 keyword functionality you would manually configure the attached bit on the Level 1 process Caution If the connectivity for the Level 2 instance is lost the attached bit in the Level instance LSP would continue sending traffic to the Level 2 instance and cause the traffic to be dropped Multicast Intact Feature The multicast intact feature provides the ability to run multicast routing PIM when IGP shortcuts are configured and active on the router Both OSPFv2 and IS IS support the multicast in
370. te policy NetworkControl The redistribute attach point allows routes from other sources to be advertised by BGP The policy attached at this point is able to set any of the valid BGP attributes on the routes that are being redistributed Likewise selection operators allow a user to control what route sources are being redistributed and which routes from those sources The following example shows how to redistribute all routes from OSPF instance 12 into BGP If OSPF were carrying a default route it is dropped Routes carrying a tag of 10 have their local preference set to 300 and the community value of 2 666 and no advertise attached All other routes have their local preference set to 200 and a community value of 2 100 set route policy sample_redistribute if destination in 0 0 0 0 0 then drop endif if tag eq 10 then set local preference 300 set community 2 666 no advertise else set local preference 200 set community 2 100 endif end policy router bgp 2 address family ipv4 unicast redistribute ospf 12 route policy sample_redistribute Cisco 10S XR Routing Configuration Guide E Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy Show bgp The show bgp attach point allows the user to display selected BGP routes that pass the given policy Any routes that are not dropped by the attached policy are displayed in a manner similar to the output of the show ip bgp command
371. tents How to Implement BGP on Cisco IOS XR Software RC 27 Enabling BGP Routing RC 28 Configuring a Routing Domain Confederation for BGP RC 31 Resetting eBGP Session Immediately Upon Link Failure RC 33 Logging Neighbor Changes RC 34 Adjusting BGP Timers RC 34 Changing the BGP Default Local Preference Value RC 35 Configuring the MED Metric for BGP RC 36 Configuring BGP Weights RC 38 Tuning the BGP Best Path Calculation RC 39 Indicating BGP Backdoor Routes RC 41 Configuring Aggregate Addresses RC 43 Redistributing iBGP Routes into IGP RC 44 Redistributing Prefixes into Multiprotocol BGP RC 46 Configuring BGP Route Dampening RC 48 Applying Policy When Updating the Routing Table RC 52 Setting BGP Administrative Distance RC 53 Configuring a BGP Neighbor Group RC 55 Configuring a BGP Neighbor RC 58 Configuring a Route Reflector for BGP RC 60 Configuring BGP Route Filtering by Route Policy RC 62 Disabling Next Hop Processing on BGP Updates RC 64 Configuring BGP Community and Extended Community Filtering RC 65 Configuring Software to Store Updates from a Neighbor RC 67 Disabling a BGP Neighbor RC 69 Resetting Neighbors Using BGP Dynamic Inbound Soft Reset RC 71 Resetting Neighbors Using BGP Outbound Soft Reset RC 71 Resetting Neighbors Using BGP Hard Reset RC 72 Clearing Caches Tables and Databases RC 73 Displaying System and Network Statistics RC 73 Monitoring BGP Update Groups RC 75 Configuration Examples for Implementing BGP on Cisco IOS
372. terface loopback0O Enters interface configuration mode and associates one or more interfaces to the area Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco 10S XR Software Command or Action Purpose Step8 end Saves configuration changes or e When you issue the end command the system prompts commit you to commit changes Uncommitted changes found commit them before Example exiting yes no cancel RP 0 RPO CPU0 router config ospf ar if end cancel or Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode RP O0 RPO CPU0 router config ospf ar if commit Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Step9 show ospf process name area id mpls Optional Displays information about the links and traffic eng link fragment fragments available on the local router for MPLS TE Example RP O0 RPO CPU0 router show ospf 1 0 mpls traffic eng link Examples This section p
373. tes on Cisco IOS XR software Related Documents Related Topic Document Title Static routes commands complete command syntax command modes command history defaults usage guidelines and examples Static and Utility Routing Commands on Cisco IOS XR Software Release 3 2 Standards Standards Title No new or modified standards are supported by this feature and support for existing standards has not been modified by this feature MIBs MIBs MIBs Link There are no applicable MIBs for this module To locate and download MIBs for selected platforms using Cisco IOS XR software use the Cisco MIB Locator found at the following URL http cisco com public sw center netmgmt cmtk mibs shtml RFCs RFCs Title No new or modified RFCs are supported by this feature and support for existing RFCs has not been modified by this feature Technical Assistance Description Link The Cisco Technical Support website contains thousands of pages of searchable technical content including links to products technologies solutions technical tips and tools Registered Cisco com users can log in from this page to access even more content http www cisco com techsupport Cisco 10S XR Routing Configuration Guide HC Cisco IOS XR Interface and Hardware Component Configuration Guide Ic Cisco IOS XR IP Addresses and Services Configuration Guide MCC Cisco IOS
374. the running configuration file and remain within the configuration session Configuring Software to Store Updates from a Neighbor Perform this task to configure the software to store updates received from a neighbor The soft reconfiguration inbound command causes a route refresh request to be sent to the neighbor if the neighbor is route refresh capable If the neighbor is not route refresh capable the neighbor must be reset to relearn received routes using the clear bgp soft command See the Resetting Neighbors Using BGP Dynamic Inbound Soft Reset section on page RC 71 Note SUMMARY STEPS Storing updates from a neighbor works only if either the neighbor is route refresh capable or if the soft reconfiguration inbound command is configured Even if the neighbor is route refresh capable and the soft reconfiguration inbound command is configured the original routes are not stored unless the always option is used with the command The original routes can be easily retrieved with a route refresh request Route refresh sends a request to the peer to resend its routing information The soft reconfiguration inbound command stores all paths received from the peer in an unmodified form and refers to these stored paths during the clear Soft reconfiguration is memory intensive 1 configure 2 router bgp autonomous system number 3 neighbor ip address Cisco 10S XR Routing Configuration Guide Implementing BGP on Cisco IOS
375. tion If none of these methods for obtaining a router ID succeeds BGP does not have a router ID and cannot establish any peering sessions with BGP neighbors In such an instance an error message is entered in the system log and the show bgp summary command displays a router ID of 0 0 0 0 After BGP has obtained a router ID it continues to use it even if a better router ID becomes available This usage avoids unnecessary flapping for all BGP sessions However if the router ID currently in use becomes invalid because the interface goes down or its configuration is changed BGP selects a new router ID using the rules described and all established peering sessions are reset We strongly recommend that the bgp router id command is configured to prevent unnecessary changes to the router ID and consequent flapping of BGP sessions BGP Default Limits Cisco IOS XR BGP imposes maximum limits on the number of neighbors that can be configured on the router and on the maximum number of prefixes that are accepted from a peer for a given address family This limitation safeguards the router from resource depletion caused by misconfiguration either locally or on the remote neighbor The following limits apply to BGP configurations e The default maximum number of peers that can be configured is 1024 The default can be changed using the bgp maximum neighbor command The limit range is 1 to 1500 Any attempt to configure additional peers beyond the ma
376. tion Guide RC 134 _Implementing OSPF on Cisco 10S XR Software Information About Implementing OSPF on Cisco 10S XR Software W e The primary IPv4 address of the interface specified by the OSPF router id command e The 32 bit numeric value specified by the router id command in global configuration mode This value must be an IPv4 address assigned to an interface on this router e By using the highest IPv4 address on a loopback interface in the system if the router is booted with saved loopback address configuration e The primary IPv4 address of an interface over which this OSPF process is running We recommend that the router ID be set by the router id command in router configuration mode Separate OSPF processes could share the same router ID in which case they cannot reside in the same OSPF routing domain Supported OSPF Network Types OSPF classifies different media into the following three types of networks by default e NBMA networks POS e Point to point networks POS e Broadcast networks Gigabit Ethernet You can configure your Cisco IOS XR network as either a broadcast or an NBMA network Using this feature you can configure broadcast networks as NBMA networks when for example you have routers in your network that do not support multicast addressing Route Authentication Methods for OSPF Version 2 OSPF Version 2 supports two types of route authentication plain text authentication and MD5 authentication
377. tion changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software Configuring OSPF Shortest Path First Throttling This task explains how to configure SPF scheduling in millisecond intervals and potentially delay SPF calculations during times of network instability This task is optional Prerequisites See the OSPF Shortest Path First Throttling section on page RC 139 for information about OSPF SPF throttling SUMMARY STEPS 1 configure 2 router ospf process name or router ospfv3 process name 3 router id ipv4 address interface type interface instance 4 timers throttle spf spf start spf hold spf max wait 5 area area id 6 interface type instance 7 end or commit 8 show ospf process name or show ospfv3 process name DETAILED STEPS Command or Action Purpose Step1 configure Enters global configuration mode Example RP 0 RPO CPU0 router configure Step2 router ospf process name Enables OSPF routing for the specified routing process and or places the router in router configuration mode router ospfv3 process name or Enables OSPFv3 routing f
378. tion session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session Configuration Examples for Implementing OSPF on Cisco IOS XR Software This section provides the following configuration examples e Cisco IOS XR for OSPF Version 2 Configuration Example page RC 188 e CLI Inheritance and Precedence for OSPF Version 2 Example page RC 189 e MPLS TE for OSPF Version 2 Example page RC 190 e ABR with Summarization for OSPFv3 Example page RC 190 e ABR Stub Area for OSPFv3 Example page RC 190 e ABR Totally Stub Area for OSPFv3 Example page RC 191 e Route Redistribution for OSPFv3 Example page RC 191 e Virtual Link Configured Through Area for OSPFv3 Example page RC 191 Cisco 10S XR Routing Configuration Guide Implementing OSPF on Cisco 10S XR Software Configuration Examples for Implementing OSPF on Cisco IOS XR Software Cisco IOS XR for OSPF Version 2 Configuration Example The following example shows how an OSPF interface is configured for an area in Cisco IOS XR software In Cisco IOS XR software area 0 must be explicitly configured with the area command and all interfaces that are in the range from 10 1 2 0 to 10 1 2 2
379. tional Monitoring BGP Update Groups page RC 75 optional Enabling BGP Routing amp Perform this task to enable BGP routing and establish a BGP routing process Configuring BGP neighbors is included as part of enabling BGP routing Note Prerequisites At least one neighbor and at least one address family must be configured to enable BGP routing At least one neighbor with both a remote AS and an address family must be configured globally using the address family and remote as commands BGP must be able to obtain a router identifier for example a configured loopback address At least one address family must be configured in the BGP router configuration and the same address family must also be configured under the neighbor Cisco 10S XR Routing Configuration Guide RC 28 _ mplementing BGP on Cisco 10S XR Software How to Implement BGP on Cisco IOS XR Software Hi Restrictions If the neighbor is configured as an external BGP eBGP peer you must configure an inbound and outbound route policy on the neighbor using the route policy command SUMMARY STEPS 1 configure 2 route policy name 3 end policy 4 end or commit 5 configure 6 router bgp autonomous system number 7 bgp router id ip address interface type interface instance 8 neighbor ip address 9 remote as autonomous system number 10 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast 11 route policy route
380. tiple routers are in restart mode it terminates any local graceful restart operation This feature utilizes the available support for changing the purge time of existing OSPFVv3 routes in the routing information base RIB When graceful restart is enabled the purge timer is set to 90 seconds by default If graceful restart is disabled the purge timer setting is 0 This feature has an associated grace LSA This link scope LSA is type 11 According to the RFC the OSPFv3 process should flush all old self originated LSAs during a restart With the Graceful Restart feature however the router delays this flushing of unknown self originated LSAs during a graceful restart OSPFv3 can learn new information and build new LSAs to replace the old LSAs When the delay is over all old LSAs are flushed Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HT How to Implement OSPF on Cisco IOS XR Software If graceful restart is enabled the adjacency creation time of all the neighbors is saved in the system database SysDB The purpose for saving the creation time is so that OSPFv3 can use the original adjacency creation time to display the uptime for that neighbor after the restart Multicast Intact Feature The multicast intact feature provides the ability to run multicast routing PIM when IGP shortcuts are configured and active on the router Both OSPFv2 and IS IS support the multicast intact feature
381. to 100 and BGP routes with a tag of 20 have their OSPFVv3 cost set to 200 Any BGP routes not carrying a tag of either 10 or 20 are not be redistributed into the OSPFV3 link state database route policy OSPFv3 redist set metric type type 2 if tag eq 10 then set cost 100 elseif tag eq 20 then set cost 200 else drop endif end policy router ospfv3 1 redistribute bgp instance_15 policy OSPFv3 redist OSPFv3 Attributes and Operators Table 6 summarizes the OSPFv3 attributes and operators Table 6 OSPFv3 Attributes and Operators Attribute Match Set cost n a set destination in n a metric type n a set rib has route in n a route type is n a tag eq ge le set Cisco 10S XR Routing Configuration Guide Implementing Routing Policy on Cisco IOS XR Software HZ Information About Implementing Routing Policy IS IS Policy Attach Points This section describes each of the IS IS policy attach points and provides a summary of the BGP attributes and operators Redistribute The redistribute attach point within IS IS allows routes from other protocols to be readvertised by IS IS The policy is a set of control structures for selecting the types of routes that a user wants to redistribute into IS IS The policy can also control which IS IS level the routes are injected into and at what metric values The following example shows how to redistribute routes from IS IS instance 1 into IS IS instance ins
382. to router 10 0 0 3 is up Adjacency State FULL Hello suppressed State is up and Adjacency State is FULL Summarizing Subnetwork LSAs on an OSPF ABR If you configured two or more subnetworks when you assigned your IP addresses to your interfaces you might want the software to summarize aggregate into a single LSA all of the subnetworks that the local area advertises to another area Such summarization would reduce the number of LSAs and thereby conserve network resources This summarization is known as interarea route summarization It applies to routes from within the autonomous system It does not apply to external routes injected into OSPF by way of redistribution This task configures OSPF to summarize subnetworks into one LSA by specifying that all subnetworks that fall into a range are advertised together This task is performed on an ABR only SUMMARY STEPS 1 configure 2 router ospf process name or router ospfv3 process name 3 router id ipv4 address interface type interface instance 4 area area id 5 range ip address mask advertise not advertise or range ipv6 prefix prefix length advertise not advertise 6 interface type instance Cisco 10S XR Routing Configuration Guide RC 164 _Implementing OSPF on Cisco 10S XR Software 7 end or commit DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Command or Action How to Implement OSPF on Cisco 10S XR Software W Purpo
383. tocol has an administrative distance of 115 If IS IS and OSPF both download 10 0 1 0 24 to RIB RIB would prefer the OSPF route because OSPF has a lower administrative distance Administrative distance is used only to choose between multiple routes of the same length The default administrative distances for the common protocols are shown in Table 2 Table 2 Default Administrative Distances Protocol Administrative Distance Default Connected or local routes 0 Static routes 1 External BGP routes 20 OSPF routes 110 IS IS routes 115 Internal BGP routes 200 The administrative distance for some routing protocols for instance IS IS OSPF and BGP can be changed See the protocol specific documentation for the proper method to change the administrative distance of that protocol Note Changing the administrative distance of a protocol on some but not all routers can lead to routing loops and other undesirable behavior Doing so is not recommended RIB Support for IPv4 and IPv6 In Cisco IOS XR software RIB tables support multicast and unicast routing The default routing table for Cisco IOS XR RIB are the unicast and the multicast unicast RIB tables for IPv4 and IPv6 routing respectively For multicast routing routing protocols insert unicast routes into the multicast unicast RIB table Multicast protocols then use the information to build multicast routes which in turn are stored in the MRIB See the
384. tonomous system number Enters BGP configuration mode allowing you to configure the BGP routing process Example RP 0 RPO CPU0 router config router bgp 120 Step3 neighbor ip address Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Step4 remote as autonomous system number Creates a neighbor and assigns it a remote autonomous system number of 2002 Example RP 0 RPO CPU0 router config bgp nbr remote as 2002 Cisco 10S XR Routing Configuration Guide RC 64 _ mplementing BGP on Cisco 10S XR Software Command or Action How to Implement BGP on Cisco IOS XR Software Hi Purpose Step 5 address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Example RP 0 RPO CPU0 router config bgp nbr address family ipv4 unicast Enters neighbor address family configuration mode for the IPv4 address family Step 6 next hop self Example RP 0 RPO CPU0 router config bgp nbr af next hop self Sets the next hop attribute for all IPv4 unicast routes advertised to neighbor 172 168 40 24 to the address of the local router Disabling the calculation of the best next hop to use when advertising a route causes all routes to be advertised with the local network device as the next hop Step7 end or commit Example RP
385. traffic engineering TE tunnels Overload Bit on Router The overload bit is a special bit of state information that is included in an LSP of the router If the bit is set on the router it notifies routers in the area that the router is not available for transit traffic This capability is useful in four situations 1 During a serious but nonfatal error such as limited memory 2 During the startup and restart of the process The overload bit can be set until the routing protocol has converged However it is not employed during a normal NSF restart or failover because doing so causes a routing flap 3 During a trial deployment of a new router The overload bit can be set until deployment is verified then cleared 4 During the shutdown of a router The overload bit can be set to remove the router from the topology before the router is removed from service Cisco 10S XR Routing Configuration Guide I RC 89 Implementing IS IS on Cisco 10S XR Software HZ Information About Implementing IS IS on Cisco 10S XR Software Default Routes You can force a default route into an IS IS routing domain Whenever you specifically configure redistribution of routes into an IS IS routing domain the Cisco IOS XR software does not by default redistribute the default route into the IS IS routing domain The default information originate command generates a default route into IS IS which can be controlled by a route map You can use the rou
386. ts routes between these two groups The route reflector and its client peers form a cluster The nonclient peers must be fully meshed with each other but the client peers need not be fully meshed The clients in the cluster do not communicate with iBGP speakers outside their cluster Cisco 10S XR Routing Configuration Guide jL RC25 Implementing BGP on Cisco IOS XR Software W Information About Implementing BGP on Cisco 10S XR Software Figure 5 More Complex BGP Route Reflector Model Partially meshed autonomous system Route ee ba G Nonclient Routes advertised _ _ Router F Noe Nonclient Cluster Router E lt B Router d _ D Client Client Client Nonclient CG SS Router A External BGP speaker 6 Figure 5 illustrates a more complex route reflector scheme Router A is the route reflector in a cluster with routers B C and D Routers E F and G are fully meshed nonclient routers When the route reflector receives an advertised route depending on the neighbor it takes the following actions e A route from an external BGP speaker is advertised to all clients and nonclient peers e A route from a nonclient peer is advertised to all clients e A route from a client is advertised to all clients and nonclient peers Hence the clients need not be fully meshed Along with route reflector aware BGP speakers it is possible to have BGP speakers that
387. tween advertisement runs is 15 seconds For Address Family IPv4 Unicast BGP neighbor version 0 Update group eBGP neighbor with no outbound policy Route refresh request 0 1 defaults to sent 0 drop received 0 Inbound path policy configured Policy for incoming advertisements is POLICY_1 0 accepted prefixes Prefix advertised 0 suppressed 0 withdrawn 0 maximum limit 524288 Threshold for warning message 75 Connections established 0 Last reset 00 01 14 dropped 0 due to BGP neighbor initialized External BGP neighbor not directly connected To illustrate the same rule the following example shows how to set the advertisement interval to 15 from the session group The timers are set to the default 60 180 because the neighbor uses a session group thus hiding the timers command in the neighbor group The inbound policy is set to POLICY_1 from the neighbor group P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 P 0 PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C PO C AAA AAA AAA AA AAA DAADA AAA AAA AA AAA Be Rr OE I Ns RP ER ie Pre FR PD SSS eS SS ee router router router router router router router router router router router router router router config router bgp 140 config bgp session group ADV config bgp sngrp advertisement interval 15 config bgp sngrp exit config bg
388. uced on the Cisco CRS 1 Release 3 0 No modification Release 3 2 Support was added for the Cisco XR 12000 Series Router Release 3 2 2 Support was added for the multicast intact feature e Prerequisites for Implementing OSPF on Cisco IOS XR Software page RC 128 e Information About Implementing OSPF on Cisco IOS XR Software page RC 128 e How to Implement OSPF on Cisco IOS XR Software page RC 144 e Configuration Examples for Implementing OSPF on Cisco IOS XR Software page RC 187 e Where to Go Next page RC 192 e Additional References page RC 193 Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HI Prerequisites for Implementing OSPF on Cisco IOS XR Software Prerequisites for Implementing OSPF on Cisco IOS XR Software The following are prerequisites for implementing OSPF on Cisco IOS XR Software You must be in a user group associated with a task group that includes the proper task IDs for OSPF commands Task IDs for commands are listed in the Cisco IOS XR Task ID Reference Guide For detailed information about user groups and task IDs see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide Configuration tasks for OSPFv3 assume that you are familiar with IPv6 addressing and basic configuration See the Implementing Network Stack IPv4 and IPv6 on Cisco IOS XR Software module of the Cisco IOS XR IP Addresses and Services
389. understand a virtual link e The key id argument is a number in the range from 1 to 255 The key argument is an alphanumeric string of up to 16 characters The routers at both ends of the virtual link must have the same key identifier and key to be able to route OSPF traffic e The authentication key key command is not supported for OSPFv3 e Once the key is encrypted it must remain encrypted Repeat all of the steps in this task on the ABR that is at the other end of the virtual link Specify the same key ID and key that you specified for the virtual link on this router end or commit Example RP 0 RPO CPU0 router config ospf ar vl end or RP 0 RPO CPU0 router config ospf ar vl commit Saves configuration changes e When you issue the end command the system prompts you to commit changes Uncommitted changes found commit them before exiting yes no cancel cancel Entering yes saves configuration changes to the running configuration file exits the configuration session and returns the router to EXEC mode Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configurati
390. uniquely identifies an OSPF routing process The process name is any alphanumeric string no Example longer than 40 characters without spaces RP 0 RPO CPU0 singlel10 hfr config router ospfv3 test Step3 graceful restart helper Disables the helper capability Example RP 0 RPO CPU0 singlel10 hfr config ospfv3 grace ful restart helper disable Displaying Information About Graceful Restart This section describes the tasks you can use to display information about a graceful restart e To see if the feature is enabled and when the last graceful restart ran use the show ospf command To see details for an OSPFV3 instance use the show ospf process name database grace command Displaying the State of the Graceful Restart Feature The following screen output shows the state of the graceful restart capability on the local router RP 0 0 CPU0 LA show ospfv3 test database grace Routing Process ospfv3 test with ID 2 2 2 2 Initial SPF schedule delay 5000 msecs Minimum hold time between two consecutive SPFs 10000 msecs Maximum wait time between two consecutive SPFs 10000 msecs Initial LSA throttle delay 0 msecs Minimum hold time for LSA throttle 5000 msecs Maximum wait time for LSA throttle 5000 msecs Minimum LSA arrival 1000 msecs LSA group pacing timer 240 secs Interface flood pacing timer 33 msecs Retransmission pacing timer 66 msecs Maximum number of configured interfaces 255 Number of external LSA 0 Checksum Sum 0000
391. unity ebgp command is configured for a neighbor group or address family group all neighbors using the group inherit the configuration Configuring the command specifically for a neighbor overrides inherited values Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software HT How to Implement BGP on Cisco 10S XR Software SUMMARY STEPS 1 configure neighbor ip address send community ebgp 9 8 FP WS DS end or commit DETAILED STEPS Step 1 Step 2 Step 3 Step 4 Step 5 Command or Action router bgp autonomous system number remote as autonomous system number address family ipv4 unicast ipv4 multicast ipv6 unicast ipv6 multicast Purpose configure Example RP O0 RPO CPU0 router configure Enters global configuration mode router bgp autonomous system number Example RP 0 RPO CPU0 router config router bgp 120 Enters BGP configuration mode allowing you to configure the BGP routing process neighbor ip address Example RP 0 RPO CPU0 router config bgp neighbor 172 168 40 24 Places the router in neighbor configuration mode for BGP routing and configures the neighbor IP address 172 168 40 24 as a BGP peer remote as autonomous system number Example RP 0 RPO CPU0 router config bgp nbr remote as 2002 Creates a neighbor and assigns it a remote autonomous system number of 2002 address family ipv4 unicast i
392. urrent configuration session without exiting or committing the configuration changes e Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session E Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software How to Implement BGP on Cisco IOS XR Software Hi Resetting Neighbors Using BGP Dynamic Inbound Soft Reset Perform this task to trigger an inbound soft reset of the specified address families for the specified group or neighbors Resetting neighbors is useful if you change the inbound policy for the neighbors or any other configuration that affects the sending or receiving of routing updates If an inbound soft reset is triggered BGP sends a REFRESH request to the neighbor if the neighbor has advertised the ROUTE_REFRESH capability To determine whether the neighbor has advertised the ROUTE_REFRESH capability use the show bgp neighbors command SUMMARY STEPS 1 show bgp neighbors 2 clear bgp ipv4 ipv6 all unicast multicast all ip address as number external soft in DETAILED STEPS Command or Action Purpose Step1 show bgp neighbors Verifies that received route refresh capability from the neighbor is enabled Example RP O0 RPO CPU0 router show bgp neighbors Step2 clear bgp ipv4 ipv all unicast Soft resets a BGP neighbor multicast all ip address as number external sof
393. uster lengths the path with the shorter cluster length is selected If a path was not received with a cluster list attribute it is considered to have a cluster length of 0 Finally the path received from the neighbor with the lower IP address is chosen Locally generated paths for example redistributed paths are considered to have a neighbor IP address of 0 See Section 9 1 2 2g of draft ietf idr bgp4 24 txt Order of Comparisons The second part of the BGP best path algorithm implementation determines the order in which the paths should be compared The order of comparison is determined as follows 1 The paths are partitioned into groups such that within each group the MED can be compared among all paths The same rules as in the Comparing Pairs of Paths section on page RC 19 are used to determine whether MED can be compared between any two paths Normally this comparison results in one group for each neighbor AS If the bgp bestpath med always command is configured then there is just one group containing all the paths Cisco 10S XR Routing Configuration Guide _ mplementing BGP on Cisco 10S XR Software Information About Implementing BGP on Cisco IOS XR Software W 2 The best path in each group is determined Determining the best path is achieved by iterating through all paths in the group and keeping track of the best one seen so far Each path is compared with the best so far and if it is better it becomes the ne
394. ut the IS IS instance brief detail level 1 2 interface Example RP 0 RPO CPU0 router show isis interface POS 0 1 0 1 brief Step13 show isis instance instance id neighbors Optional Displays information about IS IS neighbors interface type interface instance summary detail systemid system id Example RP 0 RPO CPU0 router show isis neighbors summary Setting SPF Interval for a Single Topology IPv4 and IPv6 Configuration SUMMARY STEPS This task explains how to make adjustments to the SPF calculation to tune router performance This task is optional Because the SPF calculation computes routes for a particular topology the tuning attributes are located in the router address family configuration submode SPF calculation computes routes for Level 1 and Level 2 separately When IPv4 and IPv6 address families are used in a single topology mode only a single SPF for the IPv4 topology exists The IPv6 topology borrows the IPv4 topology therefore no SPF calculation is required for IPv6 To tune the SPF calculation parameters for single topology mode configure the address family ipv4 unicast command The incremental SPF algorithm can be enabled separately When enabled the incremental shortest path first ISPF is not employed immediately Instead the full SPF algorithm is used to seed the state information required for the ISPF to run The startup delay prevents the ISPF from running for a speci
395. v4 unicast distance 116 redistribute isis 2 level 2 l interface POS0 3 0 0 address family ipv4 unicast router isis 2 is type level 1 net 49 0002 0001 0001 0002 00 address family ipv4 unicast set attached bit interface POS0 1 0 0 address family ipv4 unicast Cisco 10S XR Routing Configuration Guide E Implementing IS IS on Cisco 10S XR Software HE Where to Go Next Where to Go Next To implement more IP routing protocols see the following document modules e Implementing OSPF on Cisco IOS XR Software e Implementing BGP on Cisco IOS XR Software Additional References The following sections provide references related to implementing IS IS on Cisco IOS XR software Related Documents Related Topic Document Title IS IS commands complete command syntax command modes command history defaults usage guidelines and examples Cisco IOS XR Routing Command Reference Release 3 2 MPLS TE feature information Implementing MPLS Traffic Engineering on Cisco IOS XR Software module in the Cisco IOS XR Multiprotocol Label Switching Configuration Guide Release 3 2 Standards Standards Title Draft ietf isis ipv6 05 txt Routing IPv6 with IS IS by Christian E Hopps Draft ietf isis wg multi topology 06 txt M ISIS Multi Topology MT Routing in IS IS by Tony Przygienda Naiming Shen and Nischal Sheth Draft ietf isis traffic 05 txt IS IS Extensions for Traffic Engineerin
396. vices Command Reference Limit LSP Flooding Limiting link state packets LSP may be desirable in certain meshy network topologies An example of such a network might be a highly redundant one such as a fully meshed set of point to point links over a nonbroadcast multiaccess NBMA transport In such networks full LSP flooding can limit network scalability One way to restrict the size of the flooding domain is to introduce hierarchy by using multiple Level areas and a Level 2 area However two other techniques can be used instead of or with hierarchy Block flooding on specific interfaces and configure mesh groups Both techniques operate by restricting the flooding of LSPs in some fashion A direct consequence is that although scalability of the network is improved the reliability of the network in the face of failures is reduced because a series of failures may prevent LSPs from being flooded throughout the network even though links exist that would allow flooding if blocking or mesh groups had not restricted their use In such a case the link state databases of different routers in the network may no longer be synchronized Consequences such as persistent forwarding loops can ensue For this reason we recommend that blocking or mesh groups be used only if specifically required and then only after careful network design Cisco 10S XR Routing Configuration Guide RC 86 l _ Implementing IS IS on Cisco 10S XR Software Info
397. viously the remote autonomous system is configured directly on neighbor group GROUP_1 and the send community setting is inherited from neighbor group GROUP_2 which in turn inherits the setting from address family group GROUP_3 RP 0 RPO CPU0 router show bgp neighbor group GROUP_1 configuration neighbor group GROUP_1 remote as 1982 timers 30 90 n GROUP_2 s GROUP_3 address family ipv4 unicast capability orf prefix list both n GROUP_2 a GROUP_2 remove private AS n GROUP_2 a GROUP_2 a GROUP_3 send community ebgp n GROUP_2 a GROUP_2 send extended community ebgp n GROUP_2 a GROUP_2 soft reconfiguration inbound n GROUP_2 a GROUP_2 a GROUP_3 weight 100 n GROUP_2 The following is sample output from the show bgp neighbor group command with the inheritance keyword This output shows that the specified neighbor group GROUP_1 inherits session address family independent configuration parameters from neighbor group GROUP_2 Neighbor group GROUP_2 inherits its session parameters from session group GROUP_3 It also shows that the GROUP_1 neighbor group inherits IPv4 unicast configuration parameters from the GROUP_2 neighbor group which in turn inherits them from the GROUP_2 address family group which itself inherits them from the GROUP_3 address family group RP 0 RPO CPU0 router show bgp neighbor group GROUP_1 inheritance Session n GROUP 2 s GROUP_3 IPv4 Unicast n GROUP_2 a GROUP_2 a GROUP_3 The following is sample outpu
398. w best so far and is compared with the next path in the group 3 A set of paths is formed containing the best path selected from each group in step 2 The overall best path is selected from this set of paths by iterating through them as in step 2 Best Path Change Suppression The third part of the implementation is to determine whether the best path change can be suppressed or not whether the new best path should be used or continue using the existing best path The existing best path can continue to be used if the new one is identical to the point at which the best path selection algorithm becomes arbitrary if the router id is the same Continuing to use the existing best path can avoid churn in the network Note This suppression behavior does not comply with the IETF Networking Working Group draft ietf idr bgp4 24 txt document but is specified in the IETF Networking Working Group draft ietf idr avoid transition 00 txt document The suppression behavior can be turned off by configuring the bgp bestpath compare routerid command If this command is configured the new best path is always preferred to the existing one Otherwise the following steps are used to determine whether the best path change can be suppressed 1 If the existing best path is no longer valid the change cannot be suppressed 2 If either the existing or new best paths were received from internal or confederation peers or were locally generated for examp
399. w cisco com go marketplace Ordering Documentation Beginning June 30 2005 registered Cisco com users may order Cisco documentation at the Product Documentation Store in the Cisco Marketplace at this URL http www cisco com go marketplace Nonregistered Cisco com users can order technical documentation from 8 00 a m to 5 00 p m 0800 to 1700 PDT by calling 1 866 463 3487 in the United States and Canada or elsewhere by calling 011 408 519 5055 You can also order documentation by e mail at tech doc store mkp external cisco com or by fax at 1 408 519 5001 in the United States and Canada or elsewhere at 011 408 519 5001 Cisco IOS XR Routing Configuration Guide xii Preface Documentation Feedback Hi Documentation Feedback You can rate and provide feedback about Cisco technical documents by completing the online feedback form that appears with the technical documents on Cisco com You can send comments about Cisco documentation to bug doc cisco com You can submit comments by using the response card if present behind the front cover of your document or by writing to the following address Cisco Systems Attn Customer Document Ordering 170 West Tasman Drive San Jose CA 95134 9883 We appreciate your comments Cisco Product Security Overview Cisco provides a free online Security Vulnerability Policy portal at this URL http www cisco com en US products products_security_vulnerability_policy html
400. ways more costly than an OSPF route and used only if no OSPF route exists Interior Routers The interior routers such as R1 in Figure 6 attached to one area for example all the interfaces reside in the same area OSPF Process and Router ID An OSPF process is a logical routing entity running OSPF in a physical router This logical routing entity should not be confused with the logical routing feature that allows a system administrator known as the Cisco IOS XR Owner to partition the physical box into separate routers A physical router can run multiple OSPF processes although the only reason to do so would be to connect two or more OSPF domains Each process has its own link state database The routes in the routing table are calculated from the link state database One OSPF process does not share routes with another OSPF process unless the routes are redistributed Each OSPF process is identified by a router ID The router ID must be unique across the entire routing domain OSPF v2 obtains a router ID from the following sources in order of decreasing preference OSPF attempts to obtain a router ID in the following ways in order of preference e The 32 bit numeric value specified by the OSPF router id command in router configuration mode This value can be any 32 bit value It is not restricted to the IPv4 addresses assigned to interfaces on this router and need not be a routable IPv4 address Cisco 10S XR Routing Configura
401. within an area cannot see the detailed network topology outside the area Because of this restricted view of topological information you can control traffic flow between areas and reduce routing traffic when the entire autonomous system is a single routing domain A backbone area is responsible for distributing routing information between multiple areas of an autonomous system OSPF routing occurring outside of an area is called interarea routing The backbone itself has all properties of an area It consists of ABRs routers and networks only on the backbone As shown in Figure 6 Area 0 is an OSPF backbone area Any OSPF backbone area has a reserved area ID of 0 0 0 0 A stub area is an area that does not accept or detailed network information external to the area A stub area typically has only one router that interfaces the area to the rest of the autonomous system The stub ABR advertises a single default route to external destinations into the stub area Routers within a stub area use this route for destinations outside the area and the autonomous system This relationship conserves LSA database space that would otherwise be used to store external LSAs flooded into the area In Figure 6 Area 2 is a stub area that is reached only through ABR 2 Area 0 cannot be a stub area Not so Stubby Area NSSA NSSA is similar to the stub area NSSA does not flood Type 5 external LSAs from the core into the area but can import autonomous system external
402. work protocols and all routers in the IS IS area for Level routing or the domain for Level 2 routing must support the identical set of network layer protocols on all interfaces Cisco 10S XR Routing Configuration Guide LRC Implementing IS IS on Cisco 10S XR Software HZ Information About Implementing IS IS on Cisco 10S XR Software When single topology support for IPv6 is used only narrow link metrics also known as old style type length and value TLV arguments may be employed During single topology operation one shortest path first SPF computation for each level is used to compute both IPv4 and IPv6 routes Using a single SPF is possible because both IPv4 IS IS and IPv6 IS IS routing protocols share a common link topology Because multitopology is the default behavior in the software you must explicitly configure IPv6 to use the same topology as IPv4 enable single topology IPv6 Configure the single topology command in IPv6 router address family configuration submode of the IS IS router stanza Multitopology IPv6 Support Multitopology IPv6 support on Cisco IOS XR software for IS IS assumes that multitopology support is required as soon as it detects interfaces configured for both IPv6 and IPv4 within the IS IS stanza Nonstop Forwarding On Cisco IOS XR software NSF minimizes the amount of time a network is unavailable to its users following a route processor RP failover The main objective of NSF is to continu
403. ximum limit or set the maximum limit to a number that is less than the number of peers currently configured will fail e To prevent a peer from flooding BGP with advertisements a limit is placed on the number of prefixes that are accepted from a peer for each supported address family The default limits can be overridden through configuration of the maximum prefix limit command for the peer for the appropriate address family The following default limits are used if the user does not configure the maximum number of prefixes for the address family Cisco 10S XR Routing Configuration Guide E Implementing BGP on Cisco IOS XR Software W Information About Implementing BGP on Cisco 10S XR Software 512K 524 288 prefixes for IPv4 unicast 128K 131 072 prefixes for IPv4 multicast 128K 131 072 prefixes for IPv6 unicast A cease notification message is sent to the neighbor and the peering with the neighbor is terminated when the number of prefixes received from the peer for a given address family exceeds the maximum limit either set by default or configured by the user for that address family It is possible that the maximum number of prefixes for a neighbor for a given address family has been configured after the peering with the neighbor has been established and a certain number of prefixes have already been received from the neighbor for that address family A cease notification message is sent to the neighbor and peering
404. xternal type 2 El OSPF external type 1 E2 OSPF external type 2 E EGP i ISIS L1 IS IS level 1 L2 IS IS level 2 ia IS IS inter area su IS IS summary null candidate default U per user static route o ODR L local sS 172 73 51 0 24 is directly connected 2d20h GigabitEthernet2 2 Backup oO E2 110 1 via 10 12 12 2 POS3 0 Output of show route best local Command Example The following is sample output from the show route best local command RP 0 RP0 CPU0 router show route best local 10 12 12 1 Routing entry for 10 12 12 1 32 Known via local distance 0 metric 0 connected Routing Descriptor Blocks 10 12 12 1 directly connected via POS3 0 Route metric is 0 Output of show route connected Command Example The following is sample output from the show route connected command RP O0 RPO CPU0 router show route connected Gateway of last resort is 172 23 54 1 to network 0 0 0 0 Cc 10 2 210 0 24 is directly connected 1d21h Ethernet0O Cc 172 20 16 0 24 is directly connected 1d21h ATM4 0 1 g 10 6 100 0 24 is directly connected 1d21h Loopback1 Output of show route local Command Example The following is sample output from the show route local command RP 0 RP0 CPU0 router show route local L 10 10 10 1 32 is directly connected 00 14 36 Loopback0 L 10 91 36 98 32 is directly connected 00 14 32 Ethernet0 0 L 172 22 12 1 32 is directly connected 00 13 35 POS3 0
405. y by diverting your traffic Cisco 10S XR Routing Configuration Guide E Implementing OSPF on Cisco 10S XR Software HZ information About Implementing OSPF on Cisco 10S XR Software Note MDS5 authentication supports multiple keys requiring that a key number be associated with a key Authentication Strategies Authentication can be specified for an entire process or area or on an interface or a virtual link An interface or virtual link can be configured for only one type of authentication not both Authentication configured for an interface or virtual link overrides authentication configured for the area or process If you intend for all interfaces in an area to use the same type of authentication you can configure fewer commands if you use the area authentication command and specify the message digest keyword if you want the entire area to use MD5 authentication This strategy requires fewer commands than specifying authentication for each interface Key Rollover To support the changing of a plain text key or MDS key in an operational network without disrupting OSPF adjacencies and hence the topology a key rollover mechanism is supported As a network administrator configures the new key into the multiple networking devices that communicate some time exists when different devices are using both a new key and an old key If an interface is configured with a new key the software sends two copies of the same packe

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