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Avaya Configuring IP Exterior Gateway Protocols (BGP and EGP) User's Manual

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1. IP00025A Figure 1 2 BGP Connecting Two Autonomous Systems Running OSPF 1 4 308628 15 0 Rev 00 Exterior Gateway Protocols BGP and EGP Nortel Networks supports BGP 3 and BGP 4 e BGP 3 assumes that each advertised network is a natural class network A B or C based on its high order bits BGP 3 cannot advertise subnets or supernets e BGP 4 has no concept of address classes Each network listed in the network layer reachability information NLRI portion of an update message contains a prefix length field which describes the length of the mask associated with the network The prefix length field allows for both supernet and subnet advertisement The supernet advertisement is what makes classless interdomain routing CIDR possible See Classless Interdomain Routing on page 1 4 In addition BGP 4 supports BGP confederations and TCP MD5 message authentication This section covers the following topics Equal Cost Multipath Topic Page Peer to Peer Sessions 1 5 Stub and Multihomed Autonomous Systems 1 6 Interior BGP Routing 1 6 IBGP Route Reflector 1 7 BGP Updates Path Attributes BGP OSPFE Interaction BGP 4 Confederations BGP 4 TCP MD5 Message Authentication Peer to Peer Sessions A BGP router employs a BGP speaker which is an entity within the router that transmits and receives BGP messages and acts upon them A BGP spe
2. message to BGP speaker A Open message A to B lt speakerA speaker B N Open message B to A Keepalive message Ato B _ speaker A lt speaker B Keepalive message B to A IP0022B Figure 4 1 Establishing and Confirming a Connection Between BGP Peers All BGP speakers respond to connection requests from other speakers By default BGP attempts to initiate a connection on each interface configured for peer to peer communication If the attempt is unsuccessful BGP retries every 120 seconds default interval You can use the BCC or Site Manager to change the default retry interval or disable the initiation function by setting the retry parameter to 0 4 4 308628 15 0 Rev 00 Using the BCC Configuring BGP Peers To set the retry interval go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter retry lt interval gt interval is the number of seconds from 1 through 2 147 483 647 between attempts to initiate a peer to peer session Setting this value to 0 disables attempts to initiate a peer to peer session For example the following command causes BGP to retry every 60 seconds to establish a peer to peer session between IP interfaces 2 2 2 2 and 2 2 2 3 peer 2 2 2 2 2 2 2 3 retry 60 peer 2 2 2 2 2 2 2 3 Using Site Manager To set the retry interval complete the following steps Site Manager Procedure You do this System responds
3. Topic Page EGP Concepts and Terminology 8 2 EGP Implementation Notes 8 5 Customizing EGP on the Router 8 6 Configuring a Neighbor 8 7 308628 15 0 Rev 00 8 1 Configuring IP Exterior Gateway Protocols BGP and EGP EGP Concepts and Terminology EGP 2 is an exterior gateway protocol used to exchange network reachability information between routers in different autonomous systems In each AS routers share routing information using one or more interior gateway protocols for example RIP or OSPF The routers that serve as end points of a connection between two ASs run an exterior gateway protocol such as EGP 2 Figure 8 1 AS1 AS2 BGP connection Figure 8 1 IP00026A EGP Connection Between Two Autonomous Systems Running RIP The Nortel Networks implementation of EGP complies with RFCs 827 and 904 EGP runs over the same LAN and WAN media protocols that IP runs over including Ethernet token ring synchronous Nortel Networks Proprietary Synchronous frame relay SMDS X 25 DDN PDN Pt to Pt ATM PVC FDDI T1 El HSSI and PPP Note EGP assumes that each advertised network is a natural class network A B or C based on its h
4. 308628 15 0 Rev 00 1 9 Configuring IP Exterior Gateway Protocols BGP and EGP In addition the BGP 4 update message can include the optional path attributes listed in Table 1 3 Table 1 3 BGP 4 Optional Path Attributes Attribute Description Multiexit discriminator Chooses between paths to the destinations listed Local preference Allows AS border routers to indicate the preference they assigned to a chosen route when advertising it to IBGP peers Atomic aggregate Ensures that certain network layer reachability information NLRI is not deaggregated Aggregator Identifies which AS performed the most recent route aggregation This attribute contains the last AS number that formed the aggregate route followed by the IP address of the BGP speaker that formed the aggregate route Cluster list Lists the members of a route reflector cluster Originator ID Identifies the originator of the route into a route reflector cluster BGP community Identifies the communities to which the route belongs A community is a group of destinations that share some common property BGP OSPF Interaction RFC 1745 defines the interaction between BGP and OSPF when OSPF is the IGP within an autonomous system For routers running both protocols the OSPF router ID and the BGP ID must be the same IP address A BGP route policy must be configured to allow BGP advertisement of OSPF routes Interaction between BGP 4 a
5. Choose BGP 3 Global The Edit BGP 3 Global Parameters menu opens 11 Set the Enable parameter Click on Help or see the parameter description on page A 11 12 Click on OK You return to the Configuration Manager window 13 In the Configuration Manager window The Protocols menu opens choose Protocols 14 Choose IP The IP menu opens 15 Choose BGP The BGP menu opens 16 Choose BGP 4 Global The Edit BGP 4 Global Parameters window opens 17 Set the Enable parameter Click on Help or see the parameter description on page A 11 18 Click on OK You return to the Configuration Manager window 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Supplying a BGP Router ID The BGP identifier is the IP address of an interface on the router When you enable BGP on the router you must specify a configured IP address as the router ID You can change the router ID to the IP address of another router IP interface Note If both OSPF and BGP are running on the router the OSPF router ID and the BGP router ID must be identical In addition the router ID must match one of the IP addresses configured on the router You can use the BCC or Site Manager to supply a BGP identifier for the router Using the BCC To change the BGP router ID go to the BGP prompt for example box ip bgp and enter router id lt ijp_address gt ijp_address is the address of an
6. 1 In the Configuration Manager window choose Protocols The Protocols menu opens want to edit BGP peer parameters 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to edit parameters The parameters for that peer appear in the window Set the Connect Retry Timer parameter Click on Help or see the parameter description on page A 14 Click on Apply and then click on Done You return to the IP Interface List for BGP window 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Negotiating the BGP Version BGP peers negotiate the version of BGP that they will use to exchange routing information If you enable both BGP 3 and BGP 4 the router first attempts to use BGP 4 If the BGP peer is not a BGP 4 speaker the router uses BGP 3 By default BGP considers BGP 4 as both the minimum and maximum acceptable version for negotiation You can use the BCC or Site Manager to specify BGP 3 as the minimum or maximum acceptable version Using the BCC To specify the minimum version go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter min version lt version gt version is either bgp3 or bgp4 def
7. cccssceeeeeeeeseeeeeeeeeeeeaeeeeeeeees 3 7 Enabling BGP Interaction with OSPF and RIP osce ecccsiwceteetisietunteeenincinsretne deneeiees 3 9 Setting the Upate Interval TIMET cxicocccnpsirecencacaxesctasaraoteenaxeanntnnacarsnaaearteresdionnanaaeets 3 10 Allowing Redundant Connectione asnsucsissisiro n a 3 11 Enapling Mutibop Can MECN srsti iiavis siarada AN 3 13 Disabling and Reenabling Dynamic Policy Configuration sseseseesseesseeeeseeesseereeeee 3 15 Gontiguring the BGP Soloist Slot MaSK siasii aiiveei trusses ietivgnin phiceaa shiveless 3 16 Disabling and Reenabling Route Aggregation ccccesccccceeesecceceeeeeeeeeeeeesseeeeenenees 3 17 Enabling and Disabling Black Hole PUNCHING ccisiseccccccsenrdccmerrececemncncdeemmenceteramrancetaes 3 18 Disabling and Reenabling the BGP 4 MED Attribute oo eee eeeeeeneeeseeeneeeaaes 3 20 Goniig ring BGP 4 Confederations seperangan enaa Aa AEA 3 21 Disabling BayRS Local Preference Calculation and Route Selection cceee 3 25 Calculating BGP 4 Local Preference Values cccccccesseeeeeeeeeeeaeeeeeeeeeteeeeenaeeeee 3 25 Besi Rote UCT x ca det caccinened se scasedcascasentd seat a aaa E ENAR 3 27 Goniguring BGP Message Logging st ccisssssancegnrsenevainardesnteneaaauiiieenienieciaien 3 29 Configuring EBGP Route Flap Damping icsistacdicsseiacviconesstolesectacsiaaseiatesaasebesadedsseranpnleace 3 31 Assigning Weight Classes and Values to an AS 0 ecccc
8. Choose Accept Policies Click on the policy that you want to modify The BGP4 Accept Policy Filters window opens The parameter values for that policy appear in the window Edit one or more of the following parameters e Injection List Local Preference AS Prepend BGP Community to accept BGP Community attribute action Multi Exit Discriminator Multi Exit Discriminator Value Click on Help or see the parameter descriptions beginning on page A 40 Click on Apply and then click on Done You return to the Configuration Manager window 5 12 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies Configuring a BGP Announce Policy BGP announce policies determine which routes in the routing table BGP advertises to other routers To configure a BGP announce policy you must do the following e Supply a name for the new announce policy e Specify whether BGP ignores or advertises an update that matches the policy e Rank the policy according to precedence You can use the BCC or Site Manager to configure BGP announce policies You can configure up to 32 BGP announce policies Announce Policy Guidelines When you configure an announce policy with an empty network list and you have multiple policies configured make sure that you specify the lowest possible value for the precedence BCC or Rule Precedence Site Manager parameter in the policy that has the empty list
9. 11 12 13 14 15 16 17 18 19 Converting Cisco to Nortel Networks Equivalents Announce advertisements to peer 1 1 1 1 if the update includes an AS Path that matches 350 400 and deny updates of AS Path that contains 350 400 500 as specified by Cisco as path access list 5 and the Nortel Networks policies DenyAS and AllowAS Create a peer group named MyPeers with the following elements peer router AS is 333 advertise networks as specified by route map AdvertiseMap and accept incoming networks as specified by FilterMap Assign peer routers 1 1 1 1 and 2 2 2 2 to peer group MyPeers Nortel Networks handles the peer group concept by specifying the peer routers and AS in the similar AdvertiseMap announce policy and FilterMap accept policy Advertise the aggregate address 195 89 8 0 mask 255 255 248 0 195 89 8 0 21 as well as the more specific addresses that is 195 89 8 0 to 195 89 15 0 Advertise the aggregate address 195 89 8 0 mask 255 255 248 0 195 89 8 0 21 only To redistribute BGP routes of AS 2000 into OSPF AS 101 set the Nortel Networks global OSPF parameter AS boundary Router to true in the BCC YES in Site Manager and disable BGP s Intra AS parameter To redistribute OSPF and static routes of AS 101 into BGP AS 2000 set the BCC protocol source parameter or the Site Manager Route Source parameter to OSPF and static in the router announce policy The keepalive tim
10. 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers 7 Click on the peer for which you want to edit parameters 8 Set the Local AS to Advertise to Peer parameter Click on Help or see the parameter description on page A 16 The BGP Peer List window opens The parameters for that peer appear in the window You return to the IP Interface List for BGP window 9 Click on Apply and then click on Done Specifying a Maximum Update Size By default a BGP speaker sends update messages with a maximum size of 800 bytes You can reset the maximum update message size If the update message that advertises a single route is larger than the configured message size the actual message size can override the configured value You can use the BCC or Site Manager to specify a maximum update message size 4 14 308628 15 0 Rev 00 Using the BCC Configuring BGP Peers To specify a maximum update size go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter max update size lt bytes gt bytes is the maximum size from 64 through 4096 of updates that BGP sends on this peer session For example the following command specifies a maximum size of 950 bytes for updates sent on the peer session established between inter
11. If you use the default an empty list the actual IDs are advertised By default BGP 4 aggregates subnets into their natural network IDs If you supply a list that includes the encoding 255 255 255 255 255 255 255 255 the actual network IDs are advertised along with the other IDs in the advertise list This allows advertisement of an aggregate or default route along with the actual network If the actual network is a subnet and the advertising protocol supports subnet advertisements the subnet is advertised EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 10 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 10 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 10 A 56 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters From RIP Gateway Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of IP addresses Specifies the addresses of one or more routers that could send RIP updates to this router This policy applies to RIP advertisements from routers on this list and applies only to RIP sourced routes when RIP is included as a route source Specify one or more IP addresses Use
12. Set the following parameters Hello Timer e Poll Timer Click on Help or see the parameter descriptions beginning on page A 28 Click on Apply and then click on Done You return to the IP Interface List for EGP window 10 Click on Done You return to the Configuration Manager window 308628 15 0 Rev 00 8 13 Appendix A Site Manager Parameters This appendix contains the Site Manager parameter descriptions for BGP and EGP services Parameter descriptions are also provided for accept and announce policies You can display the same information using Site Manager online Help For information about the IP parameters that you set when enabling BGP and EGP see Configuring IP ARP RARP RIP and OSPF Services This appendix contains the following information Topic Page BGP Parameters A 2 EGP Parameters A 25 Routing Policy Parameters A 29 For each parameter this appendix provides the following information e Parameter name e Configuration Manager menu path e Default setting e Valid parameter options e Parameter function e Instructions for setting the parameter e Management information base MIB object ID 308628 15 0 Rev 00 A 1 Configuring IP Exterior Gateway Protocols BGP and EGP The Technician Interface allows you to modify parameters by issuing set and commit commands with the MIB object ID This process is equivalent to modifying parameters using
13. The following command sequence configures the router to drop advertisements to peer 1 1 1 1 if the update includes an AS path that matches 350 or 400 announce pol_4 bgp action ignore announce pol_4 bgp match match bgp announce pol_4 as path pattern 350 400 match bgp announce pol_4 Outbound peer 1 1 1 1 outbound peer 1 1 1 1 bgp announce pol_4 5 20 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies Using Site Manager To specify match criteria for a BGP 4 announce policy complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens Choose IP The IP menu opens Choose Policy Filters The Policy Filters menu opens Choose BGP 4 The BGP 4 Policies menu opens ay oO hy Choose Announce Policies 6 Click on the policy that you want to edit The BGP4 Announce Policy Filters window opens The parameter values for that policy appear in the window 7 Set the following parameters Networks Route Source External Route Source From Rip Gateway Received on Rip Interface From Ospf Router Id Received Ospf Type Received Ospf Tag From Egp Peer From Egp As Received Egp Gateway From Bgp Peer From Bgp Peer As Received Bgp Next Hop Outbound Peer As Outbound Peers As Pattern BGP Communities to match Click on Help
14. Indicate optional elements in syntax descriptions Do not type the brackets when entering the command Example If the command syntax is show ip interfaces alerts you can enter either show ip interfaces or show ip interfaces alerts Indicate that you repeat the last element of the command as needed Example If the command syntax is ethernet 2 1 lt parameter gt lt value gt you enter ethernet 2 1 and as many parameter value pairs as needed xvi 308628 15 0 Rev 00 italic text screen text separator gt vertical line Preface Indicates new terms book titles and variables in command syntax descriptions Where a variable is two or more words the words are connected by an underscore Example If the command syntax is show at lt valid_route gt valid_route is one variable and you substitute one value for it Indicates system output for example prompts and system messages Example set Trap Monitor Filters Shows menu paths Example Protocols gt IP identifies the IP option on the Protocols menu Separates choices for command keywords and arguments Enter only one of the choices Do not type the vertical line when entering the command Example If the command syntax is show ip alerts routes you enter either show ip alerts or show ip routes but not both 308628 15 0 Rev 00 xvii Configuring IP Exterior Gateway Protocols BGP and EGP Acronyms
15. 308628 15 0 Rev 00 Using Site Manager Configuring BGP Peers To set BGP 4 authentication parameters complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP 4 Choose Peers The BGP menu opens The IP Interface List for BGP window opens 5 Click on the interface that you want to edit The parameter values for that interface appear in the window 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer that you want to edit The parameter values for that peer appear in the window 8 Set the following parameters Tcp Authentication Tcp Md5 Key Storage Node Protection Key Tcp Md5 Key Click on Help or see the parameter descriptions beginning on page A 18 Note The Tcp Md5 Key Storage and Tcp Md5 Key parameters are grayed out until you select MD5 as the Tcp Authentication value 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window 10 Click on Done You return to the Configuration Manager window 308628 15 0 Rev 00 4 27 Chapter 5 Configuring BGP Accept and Announce Policies Accept and announce policies control the flow of routing information in and out of the routing table as follows e An accept po
16. Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies Disable Enable Disable Enables or disables route flap dampening Route flap dampening applies only to EBGP learned routes Accept the default Disable or specify Enable to enable route flap dampening 1 3 6 1 4 1 18 3 5 3 2 6 9 1 26 308628 15 0 Rev 00 A 45 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID BGP Route Flap Dampening Template Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies default when the Route Flap Dampening parameter is set to Enable Name of a configured route flap dampening template Specifies the name of the configured route flap dampening template to apply to the routes specified by this accept policy Enter the name of a configured route flap dampening template or accept the default template 1 3 6 1 4 1 18 3 5 3 2 6 9 1 27 Multi Exit Discriminator Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies Passthru Passthru Override Generate Delete Indicates whether to accept a multiexit discriminator value for a network matching this filter and if accepted what value to use This parameter is valid only if the value of the Ac
17. communities in the matching update Specify List of BGP a well known community name no export communities no advertise no export subconfed or enter a four octet community number in the form AS_number value Entering 0 in the two most significant bits causes the router to match on the lower 16 bits inject List of IP addresses Specifies a list of networks that BGP inserts into the routing table in place of or in addition to the advertised network This item is a BCC object with parameters of its own To specify multiple items create multiple objects For example the following command sequence specifies an override MED value of 10 for EGP routes that match accept policy pol_l accept pol_1 bgp action accept accept pol_1 bgp match match bgp accept pol_1 origin egp match bgp accept pol_1 modify modify bgp accept pol_1 med method override modify bgp accept pol_1 med 10 modify bgp accept pol_l 308628 15 0 Rev 00 5 11 Configuring IP Exterior Gateway Protocols BGP and EGP Using Site Manager To supply modification values for a BGP accept policy complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens Choose IP The IP menu opens Choose Policy Filters The Policy Filters menu opens Choose BGP 4 The BGP 4 Policies menu opens ay oO
18. deleting BGP 2 4 BGP 3 2 4 EGP 2 7 Detect Redundant Connections parameter 3 13 A 6 dynamic policy configuration for BGP enabling and disabling 3 15 E EBGP route and traffic balancing configuring 7 5 ECMP equal cost multipath configuring BGP route and traffic balancing 7 1 described 1 8 Index 2 EGP deleting from the router 2 7 enabling and disabling 8 6 implementation notes 8 5 local AS number for 8 7 neighbor acquisition mode for 8 11 enabling and disabling 8 10 gateway mode for 8 9 poll mode for 8 12 specifying address of 8 8 timers for 8 13 overview of 8 2 starting 2 6 Enable parameter BGP peer A 13 BGP weight assignments A 23 BGP 3 3 3 A 11 BGP 4 3 3 A 11 EGP 8 6 A 25 EGP neighbor 8 10 A 27 equal cost multipath ECMP configuring BGP route and traffic balancing 7 1 described 1 8 Exterior Gateway Protocol EGP 1 3 External Advertisement Timer parameter 4 10 A 14 external advertisement timer setting for BGP peers 4 9 G Gateway Mode parameter EGP neighbor 2 6 8 9 A 26 gateway protocols 1 1 H Hello Timer parameter 8 13 A 28 holddown time setting for BGP peers 4 11 Holdtime parameter 4 12 A 15 308628 15 0 Rev 00 IBGP interior BGP configuring route and traffic balancing 7 1 described 1 6 route reflector configuring 6 1 route reflector described 1 7 TTL setting 4 16 IBGP ECMP Method parameter 7 5 A 9 ibgp ecmp method command
19. By default the NEXT_HOP attribute can specify the IP address of a router other than this BGP router Configuring the peer to advertise a next hop other than itself can eliminate extra forwarding hops However you can configure the router to always send the local BGP peer s IP address as the next hop in all advertisements Using the BCC To specify whether the BGP peer router sends its own address as the next hop in advertisements go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter next hop self lt state gt state is either enabled or disabled default For example the following command causes BGP to send the local peer s IP address as the next hop in all advertisements peer 2 2 2 2 2 2 2 5 next hop self enabled peer 2 2 2 2 2 2 2 5 Using Site Manager To specify whether the BGP peer router sends its own address as the next hop in advertisements complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens continued 308628 15 0 Rev 00 4 17 Configuring IP Exterior Gateway Protocols BGP and EGP Site Manager Procedure continued You do this 5 Click on the IP interface for which you want to edit
20. Direct Static RIP OSPF with type 2 metric EGP and BGP Direct Static RIP OSPF with type 2 metric EGP BGP Specifies one or more external route source identifiers If you specify an external route source a route from that source that meets the other criteria of this policy matches the policy This parameter applies only to OSPF routes that use the new ASE type 2 metric The protocol from which OSPF received the route is encoded in the ASE metric along with the route s metric To specify any external route source use the default 1 3 6 1 4 1 18 3 5 3 2 6 10 1 9 Outbound Peer AS Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of AS numbers Specifies a list of autonomous system numbers If an AS number is included in this list this policy applies to BGP advertisements being sent to BGP peers in that AS Specify one or more AS numbers Configure an empty list to indicate that this policy applies to BGP advertisements going to peers in any AS 1 3 6 1 4 1 18 3 5 3 2 6 10 1 22 A 74 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Outbound Peers Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of IP ad
21. If you want only one BGP connection to the same router to be maintained use the default If you want to allow redundant connections enter Disable 1 3 6 1 4 1 18 3 5 3 2 5 1 1 16 A 6 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Multi hop EBGP Connection Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Disable Enable Disable Specifies whether BGP allows multihop connections to an external BGP peer By default BGP enforces the rule that requires an external BGP peer to be located on a directly attached network Use this parameter to override the restriction Enabling multihop BGP connections is dangerous because it can cause BGP speakers to establish BGP connections that traverse a third party AS possibly violating policy considerations and introducing forwarding loops 1 3 6 1 4 1 18 3 5 3 2 5 1 1 6 BGP Dynamic Policy Change Support Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Enable Enable Disable Specifies whether BGP dynamically reevaluates all routes affected by a policy when you modify the policy Select Disable if you want BGP to restart all connections when you modify a policy 1 3 6 1 4 1 18 3 5 3 2 5 1 1 19
22. Table 3 2 Slot Mask Parameter Values Value Meaning all slots default The BGP soloist can run on all slots 1 to 14 The BGP soloist can run only on the specified slots For example the following command configures slots 2 3 and 4 to be eligible to run the BGP soloist bgp slot mask 2 3 4 bgp 3 16 308628 15 0 Rev 00 Configuring Global BGP Parameters Using Site Manager To configure the BGP slot mask complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the BGP Soloist Slots parameter Click on Help or see the parameter description on page A 7 6 Click on OK You return to the Configuration Manager window Disabling and Reenabling Route Aggregation By default BGP aggregates non BGP originated subnet routes to their corresponding natural network routes for advertisement to BGP peers Disabling route aggregation causes BGP to advertise each subnet You can use the BCC or Site Manager to disable this feature This switch does not affect the advertisement of BGP originated routes Using the BCC To disable or reenable route aggregation for non BGP originated subnet routes go to the BGP prompt for example box ip bgp
23. This guide uses the following acronyms ARP AS ATM BGP CIDR DES EBGP ECMP EGP FDDI HSSI IBGP ICMP IGP IP ISP LAN MD5 MED MEK MIB MSS NLRI NPK NVRAM OSPF Address Resolution Protocol autonomous system asynchronous transfer mode Border Gateway Protocol classless interdomain routing data encryption standard Exterior Border Gateway Protocol equal cost multipath Exterior Gateway Protocol Fiber Distributed Data Interface High Speed Serial Interface Interior Border Gateway Protocol Internet Control Message Protocol interior gateway protocol Internet Protocol Internet service provider local area network Message Digest 5 multiexit discriminator message encryption key management information base maximum segment size network layer reachability information node protection key nonvolatile random access memory Open Shortest Path First xviii 308628 15 0 Rev 00 PPP PVC RARP RFC RIP RR SMDS TCP UDP WAN Preface Point to Point Protocol permanent virtual circuit Reverse Address Resolution Protocol request for comments Routing Information Protocol route reflector Switched Multimegabit Data Service Transmission Control Protocol User Datagram Protocol wide area network 308628 15 0 Rev 00 xix Configuring IP Exterior Gateway Protocols BGP and EGP Related Publications For more information about IP services refer to the following publications Reference for BCC
24. and enter subnet aggregation lt state gt state is either enabled default or disabled For example the following command disables subnet aggregation bgp subnet aggregation disabled bgp 308628 15 0 Rev 00 3 17 Configuring IP Exterior Gateway Protocols BGP and EGP Using Site Manager To disable or reenable route aggregation complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the Aggregate Subnets parameter Click on Help or see the parameter description on page A 8 6 Click on OK You return to the Configuration Manager window Enabling and Disabling Black Hole Punching If BGP advertises aggregate routes you can configure BGP to submit each aggregate route to the routing table as a black hole This setting forces the router to drop a packet whose longest matching destination prefix is the black hole route For more information about black hole routes see Configuring IP ARP RARP RIP and OSPF Services By default BGP does not submit a black hole route to the IP routing table for an aggregate route that it advertises to a BGP peer You can use the BCC or Site Manager to enable black hole punching You can also configur
25. bgp Protocols gt IP gt Policy Filters gt BGP 4 gt neighbor 1 1 1 1 filter list 5 in lp as path access list 5 permit 1000 5000 accept IncomingRoutes action accept match as path pattern 41000 5000 peer 1 1 1 1 Accept Policies gt Add Name IncomingRoutes Action ACCEPT AS Pattern 1000 45000 Peer Address 1 1 1 1 continued 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Table B 1 Cisco to Nortel Networks BGP Translation continued Item Cisco Configuration Text BCC Command Site Manager Logical Steps 9 neighbor 1 1 1 1 filter list ip bgp Protocols gt IP gt Policy Filters gt BGP 4 gt 10 out lp as path access list 10 deny 350_400_500 ip as path access list 10 permit 350_40 announce DenyAS action ignore precedence 2 match as path pattern 350 400 500 outbound peer 1 1 1 1 ip bgp announce AllowAS action announce precedence 1 match as path pattern 350 400 outbound peer 1 1 1 1 Announce Policies gt Add Name DenyAS Action IGNORE AS Pattern 350 400 500 Rule Precedence 2 Peer Address 1 1 1 1 Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies gt Add Name AllowAS Action ANNOUNCE AS Pattern 350 400 Rule Precedence 1 Peer Address 1 1 1 1 10 neighbor MyPeers peer group neighbor MyPeers remote as 333 neighbor MyPeers route map AdvertiseMap out neighbor MyPeers route map FilterMap in neighbor 1
26. gt BGP 4 gt Announce Policies Null An IP address Overrides the Next Hop path attribute with the IP address you specify To allow the existing Next Hop attribute use the default null value 1 3 6 1 4 1 18 3 5 3 2 6 10 1 30 Atomic Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies Default Default Force Ignore Allows control over the atomic path attribute By default the router automatically sets this attribute if it knows that certain networks in an aggregate range have not been included in an aggregate advertisement To include the atomic attribute even if the router does not assume one is required set the parameter to Force 1 3 6 1 4 1 18 3 5 3 2 6 10 1 31 A 78 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters As Pattern Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies Empty string Any regular expression or empty string Allows AS_PATH pattern matching Enter a valid regular expression to indicate an AS and its position in a path The policy applies to all routes whose AS path includes the AS in that position For example the expression 200 means that the policy applies to all routes whose AS_PATH attribute contains AS 200 as the last AS in
27. gt Weights 8 1 to 15 plus the infinity value of 16 Specifies the class 7 weight value to add to this AS This weight value is added to the other AS weight values in a route to determine the preference of the route and aid in route selection Either accept the current AS weight value or enter a new value Any route that traverses an AS with an AS weight of 16 infinity will not be used 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 5 A 22 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Weight Value 8 Configuration Manager gt Protocols gt IP gt BGP gt Weights 8 1 to 15 plus the infinity value of 16 Specifies the class 8 weight value to add to this AS This weight value is added to the other AS weight values in a route to determine the preference of the route and aid in route selection Either accept the current AS weight value or enter a new value Any route that traverses an AS with an AS weight of 16 infinity will not be used 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 5 Enable Configuration Manager gt Protocols gt IP gt BGP gt Weights Enable Enable Disable Enables or disables a weight assignment for a particular AS Set to Disable to disable the weight assignment for this AS set to Enable if you previously disabled this weight assignment and now want
28. the following command configures global BGP with a router ID local IP address of 2 2 2 2 ip bgp router id 2 2 2 2 bgp BGP is now running on the router with default values for all BGP parameters You customize BGP by modifying BGP parameters as described in Chapter 3 Configuring Global BGP Parameters Step 2 Defining a Peer to Peer Connection For BGP to exchange routing information with BGP peers located in other autonomous systems or within the same AS you must configure at least one peer connection To define a peer to peer connection go to the BGP prompt for example box ip bgp and enter peer local lt ocal_ip_address gt remote lt remote_ip_address gt as lt as_number gt local_ip_address is the address expressed in dotted decimal format of an IP interface on the local router remote_ip_address is the address of an IP interface on the remote peer router as_number is the number of the AS in which the remote peer is located For example the following command defines a peer to peer connection between local IP interface 2 3 3 3 and remote interface 2 3 3 4 The remote BGP peer is located in AS 4 bgp peer local 2 3 3 3 remote 2 3 3 4 as 4 peer 2 3 3 3 2 3 3 4 The BGP peer to peer relationship is established with default values for all BGP peer parameters You customize the peer to peer connection by modifying BGP peer parameters as described in Chapter 4 Configuring BGP Peers 2 2
29. 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID From EGP Peer Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of IP addresses Specifies the IP address of one or more EGP peers This policy applies to EGP advertisements authored by a router on this list and applies only to EGP source routes when EGP is included as a route source Specify one or more IP addresses Use the default empty list to indicate that this policy applies to EGP advertisements from any router EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 16 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 16 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 16 308628 15 0 Rev 00 Site Manager Parameters Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID From EGP AS Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Pol
30. 1 1 1 peer group MyPeers neighbor 2 2 2 2 peer group MyPeers 11 aggregate address 195 89 8 0 255 255 248 0 ip bgp announce AdvertiseMap action announce match outbound peer 1 1 1 1 back outbound peer 2 2 2 2 back outbound as 333 ip bgp accept FilterMap action accept match peer 1 1 1 1 back peer 2 2 2 2 back as 333 ip bgp announce AggregateNets action announce match network 195 89 8 0 255 255 248 0 range back back modify advertise 195 89 8 0 255 255 248 0 back advertise 255 255 255 255 255 255 255 255 Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies gt Add Name AdvertiseMap Action ANNOUNCE Outbound Peers 1 1 1 1 2 2 2 2 Outbound AS 333 Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies gt Add Name FilterMap Action ACCEPT Peer Address 1 1 1 1 2 2 2 2 Peer AS 333 Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies gt Add Name AggregateNets Action ANNOUNCE Network List 195 89 8 0 255 255 248 0 range Advertise List 195 89 8 0 255 255 248 0 255 255 255 255 255 255 255 255 continued 308628 15 0 Rev 00 Converting Cisco to Nortel Networks Equivalents Table B 1 Cisco to Nortel Networks BGP Translation continued Item Cisco Configuration Text BCC Command Site Manager Logical Steps 12 aggregate address ip bgp Protocols gt IP gt Policy Filters gt BGP 4 gt 195 89 8 0 255 255 248 0 announce Aggreg
31. 1 18 3 5 3 2 5 1 2 1 42 Tcp Authentication Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers None None MDS Specifies whether to use MD5 authentication for this connection Specify MD5 to enable BGP TCP MD5 authentication for this connection This also makes Tcp Md5 Key Storage and Tcp Md5 Key parameters accessible Accept the default None to disable BGP TCP MD5 authentication for this connection 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 45 A 18 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Tcp Md5 Key Storage Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers None if TCP Authentication is None Clear Text if TCP Authentication is MDS Clear Text Encrypted Specifies whether the MD5 authentication key is stored as clear text or encrypted Accept the default value Clear Text to specify no encryption for the stored key Set this parameter to Encrypted to store the MDS key in encrypted form Setting this parameter to Encrypted also makes the NPK parameter visible 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 46 Node Protection Key Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers An 8 byte value If TCP Authentication is MD5 and Tcp Md5 Key Storage is Encrypted this value
32. 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 5 308628 15 0 Rev 00 A 21 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Weight Value 5 Configuration Manager gt Protocols gt IP gt BGP gt Weights 8 1 to 15 plus the infinity value of 16 Specifies the class 5 weight value to add to this AS This weight value is added to the other AS weight values in a route to determine the preference of the route and aid in route selection Either accept the current AS weight value or enter a new value Any route that traverses an AS with an AS weight of 16 infinity will not be used 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 5 Weight Value 6 Configuration Manager gt Protocols gt IP gt BGP gt Weights 8 1 to 15 plus the infinity value of 16 Specifies the class 6 weight value to add to this AS This weight value is added to the other AS weight values in a route to determine the preference of the route and aid in route selection Either accept the current AS weight value or enter a new value Any route that traverses an AS with an AS weight of 16 infinity will not be used 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 5 Weight Value 7 Configuration Manager gt Protocols gt IP gt BGP
33. 308628 15 0 Rev 00 Starting BGP and EGP Services Starting IP and BGP with Site Manager Before you can select a protocol to run on the router you must configure a circuit that the protocol can use as an interface to an attached network For information and instructions see Configuring WAN Line Services and Configuring Ethernet FDDI and Token Ring Services After you configure the circuit you can access the Site Manager Select Protocols window Note Before you configure BGP 4 see BGP Implementation Notes on page 1 12 for information To start IP and BGP from the Select Protocols window complete the following steps Site Manager Procedure You do this System responds 1 Inthe Select Protocols window select the The IP Configuration window opens following protocols IP BGP Then click on OK 2 Set the following parameters IP Address Subnet Mask Transmit Beast Addr UnNumbered Assoc Address Click on Help or see the parameter descriptions in Configuring IP ARP RARP RIP and OSPF Services 3 Click on OK The BGP Configuration window opens 4 Set the following parameters Identifier e Local AS Click on Help or see the parameter descriptions on page A 3 5 Click on OK The BGP Peer window opens continued 308628 15 0 Rev 00 2 3 Configuring IP Exterior Gateway Protocols BGP and EGP Site Manager Procedure continued You do th
34. 4 1 18 3 5 3 2 5 1 2 1 4 Peer Mode Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers None None Reflector Internal Reflector External Indicates the route reflector mode of the remote BGP peer If the peer is a node use the default None If the peer is a route reflector in the same cluster specify Reflector Internal If the peer is a route reflector in a different cluster specify Reflector External 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 35 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Enable Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers Enabled Enabled Disabled Enables or disables a BGP peer relationship with the specified IP address Set this parameter to Disabled if you want to temporarily disable this peer relationship rather than delete it Or set it to Enabled if you previously disabled this peer relationship and now want to reenable it 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 2 Min BGP Version Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 4 3 or 4 Specifies the minimum acceptable BGP version to run on this peer connection Specify BGP 3 or BGP 4 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1
35. 8 Max BGP Version Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 4 3 or 4 Specifies the maximum acceptable BGP version to run on this peer connection Specify BGP 3 or BGP 4 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 9 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID External Advertisement Timer Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 30 seconds 1 to 2 147 483 647 Specifies the minimum number of seconds allowed between BGP updates for this peer connection The external advertisement interval controls how often the IP routing table is examined for changes BGP update messages for routes that originate outside this AS will be issued no faster than the number of seconds you specify with this parameter Either accept the current value or enter a value greater than 0 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 11 Connect Retry Timer Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 120 seconds 0 to 2 147 483 647 Specifies the maximum number of seconds allowed between TCP connection attempts for this peer connection Either accept the current value or set this parameter to some other value A value of 0 indicates that no active attempt to establish
36. BGP 4 gt Announce Policies An empty list A list of network identifiers Each identifier consists of a network number a mask and a flag to indicate whether the ID refers to a specific network or a range of networks Specifies which networks will match this policy Enter a specific encoding of 0 0 0 0 0 0 0 0 to match the default route Enter a range encoding of 0 0 0 0 0 0 0 0 to match any route Enter an empty list to match any route EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 5 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 5 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 5 308628 15 0 Rev 00 Parameter Path Path Path Default Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters Action Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies EGP Announce BGP 3 and BGP 4 Ignore Announce Ignore Specifies whether or not to advertise a route that matches this policy To advertise the route specify Announce To drop the route specify Ignore EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 6 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 6 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 6 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and
37. BGP Soloist Slots Configuration Manager gt Protocols gt IP gt BGP gt BGP Global All slots Slots 1 to 14 Specifies slots on which the BGP soloist is eligible to run Accept the default All slots to enable BGP to run on all slots To configure BGP to run as a soloist on a particular slot click on Values and specify the slot numbers 1 3 6 1 4 1 18 3 5 3 2 5 1 1 20 308628 15 0 Rev 00 A 7 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Cluster Identifier Configuration Manager gt Protocols gt IP gt BGP gt BGP Global 0 0 to 4294967295 Associates the IBGP route reflector with a cluster If this BGP router is configured as an IBGP route reflector in a cluster you must specify a cluster ID All IBGP route reflectors in the same cluster must have the same cluster ID 1 3 6 1 4 1 18 3 5 3 2 5 1 1 18 Aggregate Subnets Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Enable Enable Disable Specifies whether subnet routes from non BGP sources are aggregated to their corresponding natural network routes for advertisement to BGP peers Advertisement of BGP originated routes is not affected by this switch Set this parameter as r
38. Cisco access list 5 or the Nortel Networks policy IncomingRoutes 4 Announce advertisement of network 195 89 32 0 mask 255 255 224 0 to peer IP address 1 1 1 1 as specified by Cisco access list 10 or the Nortel Networks policy OutgoingRoutes 5 Accept incoming advertisements from peer 1 1 1 1 match on AS Path that contains either AS 333 444 or 345 and set Local Preference to 125 as specified by Cisco route map and the Nortel Networks policy IncomingMap 6 Announce advertisements to peer 1 1 1 1 and append AS Path 123 123 to all outgoing updates as specified by Cisco route map and the Nortel Networks policy setASPath Note that in the Nortel Networks command if you use as path instead of as path prepend the AS path is replaced instead of appended to 7 Announce advertisement of network 192 10 20 0 mask 255 255 255 0 to peer IP address 1 1 1 1 setting multiexit discriminator MED to 100 as specified by Cisco route map and the Nortel Networks policy AdvertiseMap In addition advertise any other networks with MED set to 50 The Nortel Networks definition requires two separate announce policies with the more specific network advertised given the higher rule precedence 8 Accept incoming advertisements from peer 1 1 1 1 of AS Path that contains either exactly AS 1000 or 5000 as specified by Cisco as path access list 5 and the Nortel Networks policy IncomingRoutes B 6 308628 15 0 Rev 00 10
39. Filters gt BGP 4 gt Announce Policies Enable Enable Disable Enables or disables this policy Set to Disable to disable the policy EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 2 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 2 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 2 A 50 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters Name Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies None Any alphanumeric character string Identifies this policy Enter a unique name for the policy EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 4 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 4 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 4 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Networks Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt
40. Gateway Protocols BGP and EGP BGP 3 Specific Announce Policy Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID External Route Source Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Any Direct Static RIP OSPF with Type 2 metric EGP BGP Any Specifies one or more external route source identifiers If you specify an external route source a route from that source that meets the other criteria of this policy matches the policy This parameter applies only to OSPF external routes that use the new ASE type 2 metric The protocol from which OSPF received the route is encoded in the ASE metric along with the route s metric To specify any external route source use the default 1 3 6 1 4 1 18 3 5 3 2 6 8 1 9 Outbound Peer AS List Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies An empty list A list of AS numbers Specifies a list of autonomous system numbers If an AS number is included in this list this policy applies to BGP advertisements being sent to BGP peers in that AS Specify one or more AS numbers Use the default empty list to indicate that this policy applies to BGP advertisements going to peers in any AS 1 3 6 1 4 1 18 3 5 3 2 6 8 1 22 A 70 308628 15 0 Rev 00 Pa
41. IP gt BGP gt BGP Debug Disable Disable Open Update Notification Keepalive Specifies which BGP messages on the specified connection are logged Use the default or select one or more BGP message types by clicking on Values 1 3 6 1 4 1 18 3 5 3 2 5 1 5 1 5 A 24 308628 15 0 Rev 00 Site Manager Parameters EGP Parameters Topic Page EGP Global Parameters A 25 EGP Neighbor Parameters A 26 EGP Global Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Enable Configuration Manager gt Protocols gt IP gt EGP gt Global Enable Enable Disable Globally enables or disables EGP on all router interfaces Set to Disable if you want to disable EGP for the entire router Set to Enable if you previously disabled EGP and now want to reenable it 1 3 6 1 4 1 18 3 5 3 2 4 1 2 Local Autonomous System ID Configuration Manager gt Protocols gt IP gt EGP gt Global 1 1 to 65535 Identifies the local autonomous system the AS to which this router belongs by the NIC assigned decimal number Either accept the current value for this parameter or enter a new value 1 3 6 1 4 1 18 3 5 3 2 4 1 7 308628 15 0 Rev 00 A 25 Configuring IP Exterior Gateway Protocols BGP and EGP EGP Neighbor Parameters Parameter Path Default Options Function
42. IP interface on the router For example the following command specifies IP address 2 2 2 2 for the BGP router ID bgp router id 2 2 2 2 bgp Using Site Manager To change the BGP router ID complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens continued 3 4 308628 15 0 Rev 00 Configuring Global BGP Parameters Site Manager Procedure continued You do this System responds 5 Set the BGP Identifier parameter Click on Help or see the parameter description on page A 4 6 Click on OK You return to the Configuration Manager window Identifying the Local AS Each autonomous system in the Internet has a unique AS ID You can use the BCC or Site Manager to supply the ID of the AS in which the BGP router is located Using the BCC To specify the ID of the local AS go to the BGP prompt for example box ip bgp and enter local as lt ocal_as gt local_as is the number of the AS from 0 through 65535 where the router resides For example the following command specifies AS 5 as the local AS bgp local as 5 bgp Using Site Manager To specify the ID of the local AS complete the following steps
43. IP show Commands part number 308603 14 20 Rev 00 Provides descriptions of all show commands for IP services including the commands that display BGP configuration and statistical data Configuring IP ARP RARE RIP and OSPF Services part number 308627 15 0 Rev 00 Provides a description of IP ARP RARP RIP and OSPF services and instructions for configuring them Configuring GRE NAT RIPSO and BFE Services part number 308625 14 20 Rev 00 Provides a description of Generic Routing Encapsulation GRE Network Address Translation NAT Revised IP Security Option RIPSO and Blacker front end services and instructions for configuring them You can print selected technical manuals and release notes free directly from the Internet Go to the www nortelnetworks com documentation URL Find the product for which you need documentation Then locate the specific category and model or version for your hardware or software product Use Adobe Acrobat Reader to open the manuals and release notes search for the sections you need and print them on most standard printers Go to Adobe Systems at the www adobe com URL to download a free copy of the Adobe Acrobat Reader You can purchase selected documentation sets CDs and technical publications through the Internet at the www1 fatbrain com documentation nortel URL XX 308628 15 0 Rev 00 Preface How to Get Help If you purchased a service contract for your Nortel Networks p
44. Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Remote Peer IP Address Configuration Manager gt Protocols gt IP gt EGP None Any IP address Specifies the IP address of the remote router that will form an EGP neighbor relationship with this router Enter the IP address in dotted decimal notation 1 3 6 1 4 1 18 3 5 3 2 4 3 1 5 Remote Autonomous System IP Address Configuration Manager gt Protocols gt IP gt EGP gt Neighbors gt EGP Neighbor gt Add None Any IP address Specifies the IP address of the remote router that will form an EGP neighbor relationship with this router Enter the IP address in dotted decimal notation 1 3 6 1 4 1 18 3 5 3 2 4 3 1 5 Gateway Mode Configuration Manager gt Protocols gt IP gt EGP gt Neighbors gt EGP Neighbor Core Core Non Core Specifies the gateway mode for this EGP neighbor If you choose Core the default the local AS to which this EGP neighbor belongs will act as a transit AS That is it will advertise networks that reside within the AS as well as within external networks If you choose Non Core the AS to which this EGP neighbor belongs will act as a stub AS That is it will advertise only networks that reside within the AS Set this parameter to Core or Non Core depending on how you want this EGP neighbo
45. Matches 0 or more sequences of the pattern Plus sign Matches 1 or more sequences of the pattern Question mark Matches 0 or 1 occurrences of the pattern Caret A Matches the beginning of the input string Dollar sign Matches the end of the input string Underscore _ Matches a comma left brace right brace left parenthesis right parenthesis the beginning of the input string the end of the input string or a space Brackets Designates a range of single character patterns Hyphen Separates the end points of a range 308628 15 0 Rev 00 Converting Cisco to Nortel Networks Equivalents Nortel Networks AS Path Pattern Matching Symbols Table B 5 summarizes the symbols used in Nortel Networks AS path pattern matching Table B 5 Nortel Networks AS Path Pattern Matching Symbols Symbol or Operator Meaning lt Denotes beginning of an AS sequence segment gt Denotes end of an AS sequence segment Denotes beginning of an AS set segment Denotes end of an AS set segment period Matches any single character including white space lt seq gt set Denotes an AS path containing a sequence in the first segment and a set in the second segment Denotes the preceding pattern occurs at the end of the AS path Denotes logical OR match this or that X Matches exactly the AS specified by X _X Matches the AS pattern beginning with X for example _99 matches 99 991 9934 X_ M
46. OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE In addition the program and information contained herein are licensed only pursuant to a license agreement that contains restrictions on use and disclosure that may incorporate by reference certain limitations and notices imposed by third parties ji 308628 15 0 Rev 00 Nortel Networks Inc Software License Agreement NOTICE Please carefully read this license agreement before copying or using the accompanying software or installing the hardware unit with pre enabled software each of which is referred to as Software in this Agreement BY COPYING OR USING THE SOFTWARE YOU ACCEPT ALL OF THE TERMS AND CONDITIONS OF THIS LICENSE AGREEMENT THE TERMS EXPRESSED IN THIS AGREEMENT ARE THE ONLY TERMS UNDER WHICH NORTEL NETWORKS WILL PERMIT YOU TO USE THE SOFTWARE If you do not accept these terms and conditions return the product unused and in the original shipping container within 30 days of purchase to obtain a credit for the full purchase price 1 License grant Nortel Networks Inc Nortel Networks grants the end user of the Software Licensee a personal nonexclusive nontransferable license a to use the Software either on a single computer or if applicable on a single authorized device identified by host ID for which it was originally acquired b to copy the Software solely for backup purposes in support of authorized use of the Software and c to use and co
47. Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Next Hop Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Null An IP address Overrides the Next Hop path attribute with the IP address you specify To allow the existing Next Hop attribute use the default null value 1 3 6 1 4 1 18 3 5 3 2 6 8 1 28 BGP Communities to Match Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies An empty list A list of BGP communities Specifies one or more BGP communities This policy applies to all BGP advertisements that match the list Supply an octet string using the following format each community ID is 4 bytes long 0 in the two most significant bits causes the router to perform the match on the lower 16 bits the default empty list means match any list 1 3 6 1 4 1 18 3 5 3 2 6 8 1 31 308628 15 0 Rev 00 A 73 Configuring IP Exterior Gateway Protocols BGP and EGP BGP 4 Specific Announce Policy Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID External Route Source Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies
48. Peers Using Site Manager To define a peer to peer session complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP 4 Choose Peers The BGP menu opens The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on Add 8 Set the following parameters e Peer Address Peer AS e Local Address Peer Mode Click on Help or see the parameter descriptions beginning on page A 11 The BGP Peer window opens 9 Click on OK You return to the BGP Peer List window 10 Click on Apply and then click on Done You return to the IP Interface List for BGP window 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Initiating a Peer to Peer Session A BGP speaker initiates a peer to peer connection by periodically issuing an open message BGP speakers respond to connection requests by returning open messages In Figure 4 1 for example BGP speaker A sends an open message to BGP speaker B to request a connection BGP speaker B responds by sending an open
49. RR client session with the IBGP route reflector For information about the IBGP route reflector see Chapter 6 Configuring a Route Reflector Equal Cost Multipath Equal cost multipath ECMP support allows a BGP speaker to perform route or traffic balancing within an AS by using multiple equal cost routes submitted to the routing table by OSPF RIP or static routes For instructions on configuring route and traffic balancing see Chapter 7 Configuring Route and Traffic Balancing For more information about equal cost multipath see Configuring IP ARP RARP RIP and OSPF Services BGP Updates BGP 3 and BGP 4 speakers exchange routing updates that include a network number and a list of autonomous systems that the routing information has passed through the AS path as well as a list of unreachable networks In addition an update includes the following e List of path attributes e Local preference value BGP 4 only See Disabling BayRS Local Preference Calculation and Route Selection on page 3 25 1 8 308628 15 0 Rev 00 Path Attributes Exterior Gateway Protocols BGP and EGP A BGP 3 update message has a variable length sequence of path attributes Each attribute includes an attribute value and an attribute description Table 1 1 lists the mandatory and optional BGP 3 path attributes Table 1 1 Attribute BGP 3 Path Attributes Description AS path Mandatory attribute containi
50. Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens continued 308628 15 0 Rev 00 3 5 Configuring IP Exterior Gateway Protocols BGP and EGP Site Manager Procedure continued You do this System responds 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the BGP Local AS parameter Click on Help or see the parameter description on page A 4 6 Click on OK You return to the Configuration Manager window Disabling and Reenabling IBGP Support By default BGP supports IBGP intra AS sessions For information see BGP Concepts and Terminology on page 1 4 A BGP transit AS should use IBGP intra AS routing A stub or multihomed AS usually does not use IBGP routing You can use the BCC or Site Manager to disable and reenable IBGP support Using the BCC To disable and reenable IBGP support go to the BGP prompt for example box ip bgp and enter intra as routing lt state gt state is either enabled default or disabled For example the following command disables IBGP bgp intra as routing disabled bgp 3 6 308628 15 0 Rev 00 Configuring Global BGP Parameters Using Site Manager To disable and reenable IBGP support complete the following steps Site Manager P
51. To change the minimum AS origination interval complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to edit parameters The parameters for that peer appear in the window 8 Set the Min AS Origination Interval parameter Click on Help or see the parameter description on page A 16 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window 308628 15 0 Rev 00 4 13 Configuring IP Exterior Gateway Protocols BGP and EGP Overriding the Local AS Number By default a BGP speaker that issues an open message to initiate a peer to peer session uses the AS number that you set with the Local AS parameter You can use Site Manager to specify a different AS number overriding the default by completing the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens
52. Using Site Manager To override the one hop rule and allow multihop connections complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the Multi hop Ebgp Connection parameter Click on Help or see the parameter description on page A 7 6 Click on OK You return to the Configuration Manager window 3 14 308628 15 0 Rev 00 Configuring Global BGP Parameters Disabling and Reenabling Dynamic Policy Configuration By default BGP reconfigures IP policies dynamically This means that if you modify a policy BGP dynamically reevaluates all affected routes in light of the modified policy BGP then sends the appropriate withdraw or update message to the affected peers BGP keeps track of the routes sent to each peer allowing for precise determination of which routes to send and which to withdraw If you modify an IP policy with this feature disabled BGP restarts all BGP connections Note There is no advantage to disabling dynamic policy configuration Disabling this parameter will adversely affect BGP protocol operation overhead and network stability You can use the following Site Manager procedure to disable and reenable dynamic policy
53. a BGP connection to the peer is to be done Incoming calls from the peers will be accepted 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 12 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Holdtime Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 90 seconds 0 or any decimal number greater than 2 Specifies the holdtime that will be inserted into an open message Upon receipt of the peer s open message the lesser of the two holdtimes will be used this must be at least 3 seconds There are two exceptions If one peer sends a zero holdtime then the nonzero holdtime is used If both peers send zero holdtimes then no holdtime is used and no periodic keepalive message is sent The calculated holdtime is the amount of time either peer will wait for a keepalive or update message before declaring the connection down Either accept the current value or set the parameter to 0 or some value greater than 2 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 13 KeepAlive Timer Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 30 seconds Any decimal number in the range 1 to 2147483647 Specifies how often keepalive messages will be sent across this peer connection If a holdtime of 0 is negotiated no periodic keepalive messages are sent Other
54. and proper construction of BGP path attributes more difficult e For any router supporting both BGP and OSPF the OSPF router ID and the BGP identifier must be set to the same IP address e For BGP to run as a soloist Internet service provider ISP mode must be enabled For instructions on enabling ISP mode see Configuring IP ARP RARP RIP and OSPF Services e In configurations where BGP speakers reside on routers that have multiple network connections over multiple IP interfaces the typical case for IBGP speakers consider using the address of the router s circuitless virtual IP interface as the local peer address In this way you ensure that BGP is reachable as long as there is an active circuit on the router For instructions on configuring the circuitless or virtual IP interface see Configuring IP ARP RARP RIP and OSPF Services e By default an external BGP speaker will neither advertise any routes to a peer nor inject any routes into its IGP Configure route policies to enable any route advertisement For instructions on configuring policies see Chapter 5 Configuring BGP Accept and Announce Policies 308628 15 0 Rev 00 Exterior Gateway Protocols BGP and EGP Coordinate routing policies among all BGP speakers within an AS so that every BGP border router within an AS constructs the same path attributes for an external path Configure accept and announce policies on all IBGP connections to accept
55. any default direct static rip ospf egp bgp Specifies one or more external route source identifiers This parameter applies only to OSPF routes that use the ASE type 2 metric The protocol from which OSPF received the route is encoded in the ASE metric along with the route s metric If you specify an external route source a route from that source that meets the other criteria of this policy matches the policy To specify any external route source use the default value ospf type any default type type2 external internal Specifies which types of OSPF routes match this policy and applies only to OSPF sourced routes when OSPF is included as a route source protocol source any default direct Specifies one or more route source identifiers If you select a route source ID a route from static that source that meets the other criteria of this rip policy matches the policy ospf egp bgp continued 308628 15 0 Rev 00 5 17 Configuring IP Exterior Gateway Protocols BGP and EGP Table 5 5 BCC Match Parameters for BGP Announce Policies continued Parameter Values Function community no export Specifies a BGP community This policy no advertise applies to all BGP advertisements that match no export subconfed one or more communities in the list Specify List of BGP one of the well known community names communities no export no advertise no export subconfed or enter a f
56. be advertised for a network matching this policy and if advertised what value to use Select one of the following none to indicate that no value is to be advertised specified to indicate that the value you specify for the med parameter is to be used originating to indicate that the metric from the originating protocol is to be used This parameter is valid only if the action parameter is set to announce next hop 0 0 0 0 default IP address Overrides the next hop path attribute with the IP address that you specify continued 308628 15 0 Rev 00 5 23 Configuring IP Exterior Gateway Protocols BGP and EGP Table 5 6 BCC Modification Parameters for BGP Announce Policies continued Parameter Values Function origin none default Specifies an origin attribute override The igp egp incomplete origin attribute of a route matching this policy is replaced with the indicated value community method as is default Specifies the action to take on the remove community attribute in updates matching this append policy If you set this parameter to append or replace replace use the community parameter to specify one or more communities that will be appended to or substituted for the communities in the matching update community no export Specifies one or more communities that will no advertise be appended to or substituted for the no export subconfed
57. bgp accept pol_l To specify an override value enter lt parameter gt lt value gt Table 5 3 lists the parameters and values that you can enter Table 5 3 BCC Modification Parameters for BGP Accept Policies Parameter Values Function as path prepend List of AS numbers Specifies AS numbers that BGP adds to the AS path before it adds the local AS to the path local preference 0 default to Specifies an override value for the local 4294967295 preference attribute med method passthru default Indicates whether a multiexit discriminator override MED metric is used for a network matching generate this policy and what value to use delete med 1 0 or any positive Specifies a metric for the MED attribute integer through 2 147 483 647 continued 5 10 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies Table 5 3 BCC Modification Parameters for BGP Accept Policies continued Parameter Values Function community method as is default Specifies the action to take on the remove community attribute in updates matching this append policy If you set this parameter to append or replace replace use the community parameter to specify one or more communities that will be appended to or substituted for the communities in the matching update community no export Specifies one or more communities that will no advertise be appended to or substituted for the no export subconfed
58. border gateway is available An AS with more than one BGP speaker can use IBGP to provide a transit service for networks outside the AS An AS that provides this service is called a transit AS Figure 1 3 308628 15 0 Rev 00 Exterior Gateway Protocols BGP and EGP aS BGP B IP0021A Figure 1 3 Transit AS In Figure 1 3 AS 20 is the transit AS It provides information about its internal networks as well as transit networks to the remaining ASs The IBGP connections between BGP routers A B and C provide consistent routing information to the ASs IBGP Route Reflector A BGP router configured for IBGP establishes a peer to peer session with every other IBGP speaker in the AS In an AS with a large number of IBGP speakers this full mesh topology can result in high bandwidth and maintenance costs For example a full mesh topology for an AS with 50 IBGP speakers requires 1225 internal peer to peer connections 308628 15 0 Rev 00 1 7 Configuring IP Exterior Gateway Protocols BGP and EGP To avoid the high costs of a full mesh topology to support IBGP speakers within a large AS you can configure a router to function as an IBGP route reflector RR An IBGP speaker that needs to communicate with other BGP speakers in the AS establishes a single peer to peer
59. confederation by entering bgp peer 192 32 194 1 192 32 194 2 as 65000 Router 3 peer 192 32 194 1 192 32 194 2 back bgp peer 192 32 194 5 192 32 194 6 as 65001 Router 6 peer 192 32 194 5 192 32 194 6 back bgp peer 192 32 195 2 192 32 195 1 as 65002 Router 8 peer 192 32 195 2 192 32 195 1 back bgp peer 192 32 195 5 192 32 195 6 as 65002 Router 9 peer 192 32 195 5 192 32 195 6 back bgp Specify BGP peers in another AS or confederation with their local AS number if not a confederation or their confederation ID if a confederation by entering bgp peer 192 32 195 1 192 32 195 2 as 55 peer 192 32 195 1 192 32 195 2 back bgp Note A sub AS number cannot be the same as any external BGP peer AS however internal sub AS numbers can be assigned to a sub AS in another confederation Suggestion Use the reserved AS number range IANA reserved numbers are 64512 through 65535 3 22 308628 15 0 Rev 00 Configuring Global BGP Parameters Sub AS 65001 Router 4 Router 5 C Router 6 C T I Router 1 Ld Router 2 CE Router 7 Router 3 To AS 55 Router 8 Router 9 IP0107A Figure 3 1 BGP Confederation 308628 15 0 Rev 00 3 23 Configuring IP Exterior Gateway Protocols BGP and EGP Using Si
60. executes In active mode a router sends Hello and poll messages to request reachability status from its neighbor In passive mode a router responds to Hello and poll messages with I H U and update messages Accept the default value Both or set to either Active or Passive depending on the neighbor reachability algorithm that you want this router to execute 1 3 6 1 4 1 18 3 5 3 2 4 3 1 8 308628 15 0 Rev 00 A 27 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Hello Timer Configuration Manager gt Protocols gt IP gt EGP gt Neighbors gt EGP Neighbor 60 seconds 30 to 120 seconds Specifies the number of seconds between the local EGP neighbor s EGP Hello message retransmissions This variable represents the RFC 904 T1 timer Accept the default value of 60 seconds for this parameter or set it to a value from 30 through 120 seconds 1 3 6 1 4 1 18 3 5 3 2 4 3 1 9 Poll Timer Configuration Manager gt Protocols gt IP gt EGP gt Neighbors gt EGP Neighbor 180 seconds 120 to 480 seconds Specifies the time period in seconds between the local EGP neighbor s EGP poll message retransmissions This variable represents the RFC 904 T2 timer Accept the default value of 180 seconds for this parameter or set it to a value from 120 th
61. fails the peers can communicate over another link The disadvantage is that such a configuration results in multiple copies of each route You can use the BCC or Site Manager to disable redundancy checking and to specify the maximum number of redundant routes that BGP allows By default BGP allows up to 255 redundant routes 308628 15 0 Rev 00 3 11 Configuring IP Exterior Gateway Protocols BGP and EGP Using the BCC To disable or reenable redundancy checking go to the BGP prompt for example box ip bgp and enter redundant connection lt state gt state is either enabled default or disabled To specify the maximum number of redundant routes go to the BGP prompt and enter max redundant routes lt max_routes gt max_routes is the maximum number of redundant routes from 0 through 255 For example the following command sequence disables BGP redundancy checking allowing BGP to establish multiple TCP sessions on different physical connections with the same remote peer and configures BGP to maintain up to 50 redundant routes bgp redundant connection disabled bgp max redundant routes 50 bgp The following command reenables redundancy checking to allow only one TCP session with the same remote peer bgp redundant connection enabled bgp Using Site Manager To disable or reenable redundancy checking complete the following steps Site Manager Procedure You do this System respond
62. gt IP gt Policy Filters gt BGP 4 gt Accept Policies 1 1 to 16 Assigns a metric value the higher the number the greater the preference to a route that the protocol forwards to the routing table manager If confronted with multiple routes to the same destination the routing table manager may need to use this value to decide which route to insert Either accept the default value 1 or enter a new value Routes for all networks 0 0 0 0 0 0 0 0 should have the lowest preference and routes for the most specific networks longest address and mask should have the highest preference EGP 1 3 6 1 4 1 18 3 5 3 2 6 5 1 7 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 7 1 7 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 9 1 7 308628 15 0 Rev 00 A 33 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Rule Precedence Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies 0 A metric value Assigns a metric value to this policy a policy with a higher value takes precedence over a policy with a lower value Use this value to specify the order of precedence for policies that match th
63. is the one configured as the node protection key in the wi_key_file_path environment variable Not used if TCP Authentication is None ASCII character string Used as a cryptographic key for protecting sensitive MIB objects The NPK value is stored in nonvolatile memory NVRAM The IP security software performs a hash of the NPK value which it places in a special MIB attribute The NPK value stored in NVRAM is unique to the router It is used to encrypt the cipher and integrity keys before they are stored in the router MIB In the context of BGP 4 if the Tcp Authentication parameter is MD5 and the Tep Md5 Key Storage parameter is Encrypted the value of the NPK is used to encrypt the Tcp Md5 Key value Enter a 16 digit hexadecimal value Enter the prefix Ox before the 16 digits This value is configurable with the secure shell of the Technician Interface as described in Configuring IPsec Services None Available 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Tcp Md5 Key Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers Not used if the Tcp Authentication parameter is None or if Tcp Md5 Key Storage parameter is Clear Text No default if the Tcp Md5 Key Storage parameter is Encrypted ASCII character string Specifies the key to use for MD5 authentication The parameter value you speci
64. may pertain to or accompany the delivery of this computer software the rights of the United States Government regarding its use reproduction and disclosure are as set forth in the Commercial Computer Software Restricted Rights clause at FAR 52 227 19 Statement of Conditions In the interest of improving internal design operational function and or reliability Nortel Networks Inc reserves the right to make changes to the products described in this document without notice Nortel Networks Inc does not assume any liability that may occur due to the use or application of the product s or circuit layout s described herein Portions of the code in this software product may be Copyright 1988 Regents of the University of California All rights reserved Redistribution and use in source and binary forms of such portions are permitted provided that the above copyright notice and this paragraph are duplicated in all such forms and that any documentation advertising materials and other materials related to such distribution and use acknowledge that such portions of the software were developed by the University of California Berkeley The name of the University may not be used to endorse or promote products derived from such portions of the software without specific prior written permission SUCH PORTIONS OF THE SOFTWARE ARE PROVIDED AS IS AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES
65. no peer exists from this speaker to neighbor ASs that are members of this local confederation Specifies the peer list of this BGP speaker that is its peers in other member sub ASs within the same confederation Set this parameter as required 1 3 6 1 4 1 18 3 5 3 2 5 1 1 29 BGP IGP Interaction Control Configuration Manager gt Protocols gt IP gt BGP gt BGP Global No Interaction No Interaction BGP to OSPF BGP to RIP BGP to OSPF and RIP Specifies whether you want to import EBGP routes into an OSPF domain a RIP domain or into both an OSPF domain and a RIP domain Select the appropriate option If you specify a value of No Interaction there is no BGP IGP interaction 1 3 6 1 4 1 18 3 5 3 2 5 1 1 30 A 10 308628 15 0 Rev 00 Site Manager Parameters BGP 3 Global Parameter Parameter Path Default Options Function Instructions MIB Object ID Enable Configuration Manager gt Protocols gt IP gt BGP gt BGP 3 Global Enable Enable Disable Globally enables or disables BGP 3 on all router interfaces Set to Disable if you want to disable BGP 3 for the entire router 1 3 6 1 4 1 18 3 5 3 2 5 2 1 2 BGP 4 Global Parameter Parameter Path Default Options Function Instructions MIB Object ID Enable Configuration Manager gt Protocols gt IP gt BGP gt BGP 4 Global Enable Enable Disable Globally enables or disables BGP 4 on all router interfaces Set to Disable if
66. on Apply and then click on Done You return to the Configuration Manager window 8 10 308628 15 0 Rev 00 Choosing the Acquisition Mode Customizing EGP Services In an EGP neighbor relationship one router is the active neighbor and the other router is the passive neighbor The router in the active mode is the initiator By default EGP assumes that the remote router is the active neighbor To identify the remote router as the passive neighbor complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens edit 2 Choose IP The IP menu opens 3 Choose EGP The EGP menu opens 4 Choose Neighbors The IP Interface List for EGP window opens 5 Click on the IP interface that you want to The parameter values for that interface appear in the window 6 Click on EGP Neighbor The EGP Neighbors List window opens 7 Click on the address of the EGP neighbor that you want to edit The parameter values for that neighbor appear in the window Set the Acquisition Mode parameter Click on Help or see the parameter description on page A 27 Click on Apply and then click on Done You return to the IP Interface List for EGP window 10 Click on Done You return to the Configuration Manager window 308628 15 0 Rev 00 8 11 Co
67. or see the parameter descriptions beginning on page A 52 8 Click on Apply and then click on Done You return to the Configuration Manager window 308628 15 0 Rev 00 5 21 Configuring IP Exterior Gateway Protocols BGP and EGP Supplying Modification Values for a BGP Announce Policy You can use the BCC or Site Manager to supply values that BGP uses to modify fields in an update that matches the policy Using the BCC To supply override values for routes that match a BGP announce policy go to the announce policy prompt for example box ip bgp announce policy_1 and enter modify For example the following command invokes the modification prompt for BGP announce policy pol_1 announce pol_1 bgp modify modify bgp announce pol_1 To supply an override value enter lt parameter gt lt value gt Table 5 6 lists the parameters and values that you can enter Table 5 6 BCC Modification Parameters for BGP Announce Policies Parameter Values Function as path null default or an Specifies an AS path that overrides the AS path AS path attribute of a route matching this policy An AS path is composed of AS path segments Each path segment includes a path segment type a path segment length specifying the number of ASs in the segment and a path segment value containing one or more AS numbers There are two AS path segment types type 1 an unordered set of ASs that a route in the update messa
68. programs 4 Limitation of liability IN NO EVENT WILL NORTEL NETWORKS OR ITS LICENSORS BE LIABLE FOR ANY COST OF SUBSTITUTE PROCUREMENT SPECIAL INDIRECT INCIDENTAL OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES RESULTING FROM INACCURATE OR LOST DATA OR LOSS OF USE OR PROFITS ARISING OUT OF OR IN CONNECTION WITH THE PERFORMANCE OF THE SOFTWARE EVEN IF NORTEL NETWORKS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES IN NO EVENT SHALL THE LIABILITY OF NORTEL NETWORKS RELATING TO THE SOFTWARE OR THIS AGREEMENT EXCEED THE PRICE PAID TO NORTEL NETWORKS FOR THE SOFTWARE LICENSE 5 Government licensees This provision applies to all Software and documentation acquired directly or indirectly by or on behalf of the United States Government The Software and documentation are commercial products licensed on the open market at market prices and were developed entirely at private expense and without the use of any U S Government funds The license to the U S Government is granted only with restricted rights and use duplication or disclosure by the U S Government is subject to the restrictions set forth in subparagraph c 1 of the Commercial Computer Software Restricted Rights clause of FAR 52 227 19 and the limitations set out in this license for civilian agencies and subparagraph c 1 ii of the Rights in Technical Data and Computer Software clause of DFARS 252 227 7013 for agencies of the Department of Defense or their successors whichever is ap
69. responds with an open message that also contains a holddown time value If the BGP speakers establish a session they use the lesser value which must be greater than 2 seconds There are two exceptions to this rule e If one peer sends a nonzero holddown time the peers use the nonzero holddown time on the session e If both peers send zero holddown times the peers observe no holddown time on the session By default BGP inserts a value of 90 seconds into the open message You can use the BCC or Site Manager to reset the holddown time value or to disable the holddown function by setting this value to 0 Using the BCC To specify a holddown time go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter holddown lt seconds gt seconds is the number of seconds from 3 through 2 147 483 647 that BGP waits for a keepalive or update message before declaring the connection down For example the following command sets the holddown time to 60 seconds for the peer session established between interfaces 2 2 2 2 and 2 2 2 5 peer 2 2 2 2 2 2 2 5 holddown 60 peer 2 2 2 2 2 2 2 5 308628 15 0 Rev 00 4 11 Configuring IP Exterior Gateway Protocols BGP and EGP Using Site Manager To specify a holddown time complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose
70. return to the Configuration Manager window 8 6 308628 15 0 Rev 00 Supplying a Local AS Number Customizing EGP Services Each autonomous system has a NIC assigned decimal number ID You must supply the AS ID for the local autonomous system the AS to which this router belongs To supply or change the local AS number complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose EGP The EGP menu opens 4 Choose Global The Edit EGP Global Parameters window opens 5 Set the Local Autonomous System ID parameter Click on Help or see the parameter description on page A 25 6 Click on OK You return to the Configuration Manager window Configuring a Neighbor You define a neighbor to neighbor relationship by setting EGP neighbor parameters as described under the following topics Topic Page Specifying the Neighbor s Address 8 8 Specifying the Gateway Mode 8 9 Enabling and Disabling the Neighbor Relationship 8 10 Choosing the Acquisition Mode 8 11 Choosing the Poll Mode 8 12 Setting Neighbor Timers 8 13 308628 15 0 Rev 00 8 7 Configuring IP Exterior Gateway Protocols BGP and EGP Specifying the Neighbor s Address You define the nei
71. rnme tr Monat fern Tr mtrcen Teoernneer rer tr Treen Tr 1 8 PY TUN EG aieiaa raa a ORNE 1 9 BOF OSPF IMmaracidi poni cnmaitlah depuis A Miaana ntaag Nite 1 10 POPAO edaran aipa a TE EOI 1 11 BGP 4 TCP MDS Message Authentication ccccccccecsecsseceatiessesesesseeeensntenesseneee 1 11 BGP implementation Notes ssa se cise aaite huss sn ha Siu san ati as eater a ai iaaa 1 12 308628 15 0 Rev 00 V Chapter 2 Starting BGP and EGP Services Staring BGP Wie BGC derocar aaier a aE EEEE 2 1 Sep T COU Fa BOR iasadan aa kaaa A N aaan vase 2 1 Step 2 Defining a Peer to Peer Connection cceecceeeteeeeeeeeeeeeaeeeeeneeeeeaeeeeeneeeeees 2 2 Starting IP and BGP with Site Manager sccsi ce aiieeiienss in a aa 2 3 Deleting BGP with Site Manager cccccccscccccssecesseeecsseeeesseecsaesesaeeesseeeessaeeeseasees 2 4 Deleting BGP 3 and BGP 4 with Site Manager cscceeceeceeseeeeeeeeeceeeeeenaeeeeenees 2 5 Starting IP and EGP with Site Manager scssssesssessenvienss atv acnied uses naatetsaestenass 2 6 Deleting EGP tom the Router sracnak antaa 2 7 Chapter 3 Configuring Global BGP Parameters Disabling ahd Reenabling BaP cciioncciultaniatenicandtusivinetuueian Gada a a aai 3 2 Sp Oine a BOP Rater I sorrie iE a AEE 3 4 Jentrig Pe Loci A runaat A ERN 3 5 Disabling and Reenabling IBGP SUPpOrTE sscciccsccstsctassssscecsccccsaucasssatcosadeasebessiercgerasaneaned 3 6 Specifying Route Types for IBGP Advertisements
72. routes learned through an IBGP connection to another IBGP peer Minimize the instability caused by route flapping Confederations reduce the number of peers in an AS by breaking the network into multiple smaller ASs The BCC redundant connection parameter if enabled allows redundant BGP connections to the same router The Site Manager Detect Redundant Connections parameter if disabled allows redundant BGP connections to the same router Show BGP routing table Show status of BGP peers Show the router s BGP timers The Cisco show ip bgp neighbor command displays the keepalive holddown and external advertisement timers Display the router s announce policies The Cisco show ip bgp neighbor command displays the router s incoming and outgoing route filters Show BGP routes between peers 1 1 1 1 and 1 1 1 2 Display the BGP routes for either AS 123 or 456 See Table B 4 for information about the arguments that are available for these commands Show a summary of BGP global parameters Reset a neighbor s BGP connection Display BGP updates changes as they occur Show any BGP errors Display the IP routing table 308628 15 0 Rev 00 B 9 Configuring IP Exterior Gateway Protocols BGP and EGP 17 Discover the routes that the router s packets take when traveling to destination 1 1 1 1 Other operational differences include the following e Cisco After peering to a neighbor is established all incoming
73. specific encoding of 0 0 0 0 0 0 0 0 exact to match the default route Enter a range encoding of 0 0 0 0 0 0 0 0 range to match any route Use the default empty list to match any route originating as List of AS numbers Specifies an autonomous system This policy applies to BGP advertisements that originate from this AS peer List of IP addresses Specifies a BGP peer This policy applies to BGP advertisements from this peer This item is a BCC object with parameters of its own To specify multiple items create multiple objects Examples The following command sequence configures the router to accept incoming advertisements from network 128 1 0 0 255 255 0 0 sent by peer 1 1 1 1 accept pol_1 bgp action accept accept pol_1 bgp match match bgp accept pol_1 network 128 1 0 0 255 255 0 0 range network 128 1 0 0 255 255 0 0 range bgp accept pol_1 back match bgp accept pol_1 peer 1 1 1 1 peer 1 1 1 1 bgp accept pol_1l The following command sequence configures the router to accept incoming advertisements that contain either AS 333 444 or AS 345 accept pol_2 bgp action accept accept pol_2 bgp match match bgp accept pol_2 aS path pattern 333 4441345 match bgp accept pol_2 5 8 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies Using Site Manager To specify match criteria for a BGP accept policy complete the following steps Site Manager Procedure Yo
74. that the policy applies to BGP advertisements originating from any AS use the default empty list 1 3 6 1 4 1 18 3 5 3 2 6 7 1 12 308628 15 0 Rev 00 A 37 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Route Origin Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies Any Any IGP EGP IGP or EGP Incomplete Incomplete or IGP Incomplete or EGP Specifies the values of the BGP origin path attribute that apply to this policy Select the origin values you want to accept for this policy 1 3 6 1 4 1 18 3 5 3 2 6 7 1 13 BGP 3 Route Preference Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies 1 1 to 16 Specifies a value that is used to compare a route that matches this policy with other BGP 3 routes that match the policy The larger the value the greater the preference To specify maximum preference enter 16 This parameter is valid only if the Action parameter is set to Accept 1 3 6 1 4 1 18 3 5 3 2 6 7 1 14 Weight Class Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies Weight class 1 Weight class 1 to weig
75. the Configuration Command Equivalents Table B 6 Comparing the Operational Commands B 8 Interpreting the Operational Commands Table B 9 Comparing BGP Route Selection Processes B 11 Regular Expression Symbols B 12 Nortel Networks AS Path Pattern Matching Symbols B 13 Configuration Command Equivalents Table B 1 lists the Nortel Networks BCC and Site Manager equivalents for Cisco router configuration commands In this table bold text indicates information that the user supplies The numbered list following the table describes the functions that the correspondingly numbered table row configures 308628 15 0 Rev 00 B 1 Configuring IP Exterior Gateway Protocols BGP and EGP Table B 1 Cisco to Nortel Networks BGP Translation Item Cisco Configuration Text BCC Command Site Manager Logical Steps 1 router bgp 333 ip bgp router id 1 1 1 1 Protocols gt IP gt BGP neighbor 1 1 1 2 remote as local as 333 IP Address 1 1 1 1 444 peer 1 1 1 1 1 1 1 2 Subnet Mask 255 0 0 0 as 444 Identifier 1 1 1 1 Local AS 333 Peer Address 1 1 1 2 Peer AS 444 Local Address 1 1 1 1 2 network 1 1 1 0 ip bgp Protocols gt IP gt Policy Filters gt mask 255 255 255 0 announce OutgoingRoutes BGP 4 gt Announce Policies gt Add action announce Name OutgoingRoutes modify advertise 1 1 1 0 24 Action ANNOUNCE Advertise gt List Network Number 1 1 1 0 Network Mask 255 255 255 0 3 neighbor 1 1 1 1 ip bgp Protocols gt IP gt Policy F
76. the default empty list to indicate that this policy applies to RIP updates from any router EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 11 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 11 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 11 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Received on RIP Interface Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of IP addresses Specifies the addresses of one or more interfaces on this router This policy applies to RIP advertisements received on the interfaces in this list and applies only to RIP sourced routes when RIP is included as a route source Specify one or more IP addresses Use the default empty list to indicate that this policy applies to RIP updates received on any interface EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 12 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 12 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 12 A 58 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameter
77. the path 1 3 6 1 4 1 18 3 5 3 2 6 10 1 32 BGP Community to announce Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of BGP communities Specifies a list of one or more BGP communities to associate with this policy Set the BGP Community attribute action parameter to Append or Replace and supply a list of communities as an octet string using the following format each community ID is 4 bytes long 0 in the two most significant bits causes the router to perform the match on the lower 16 bits the default empty list means announce any list 1 3 6 1 4 1 18 3 5 3 2 6 10 1 33 308628 15 0 Rev 00 A 79 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID BGP Community attribute action Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies As Is As Is Remove Append Replace Specifies the action to be taken on the BGP communities attribute in updates matching this policy Use the default As Is if you want the BGP Communities attribute to remain unchanged Select Remove to remove all BGP communities from an update Select Append to add to the update the communities that you have specified with the BGP Community to announce para
78. tree ere trrerrer A 11 BGP Peer Parente aise anicensaato asinine ena meatier meres A 11 BGP AS Weight and Weight Class Parameters ccccccsseeseeeeeeeteeeeeneeeeeeeees A 20 BGP Event Message Paramelerg cu ccsscccssstacds ceccesnedatsxensiieatiednueaantvbindeacnhacduasewiers A 24 viii 308628 15 0 Rev 00 ECOPRENSA A 25 EGP GODA PAAIE oinas anaana a aN aA ATN ai AE A 25 EGP Neighbor ParainGierg t cissendesrieetsttenti onde eed oieate A 26 Romima Folicy Perea ee roirnainiorikn aaa A A 29 Common Accept Policy Parameters cccssacciaiczsesesscenacceussacoeesmsancaenteanaceseseaaneaceemaseds A 29 EGP Spsotic Accept Policy ParamigterS is csicctccccsaccccaccicesscetasniedaascendeeedonateneasctensee A 34 BGP 3 Specitic Accept Policy Parameters cocscsicesscccsescdcssssccencetsrecsccssaurortssoneens A 36 BGP 4 Specific Accept Policy Parameters c cccccccceeeceeeeeeeeeeeeeeseeeeeeeeaaeeeeeeeees A 40 Common Announce Policy Parameters cc ccccccsesesceeceeeeeeeeeeseeeeeeseaeeseeneeesaees A 50 EGP Specific Announce Policy Parameters ccccsscsesesscececseeeeeceeeeeeeeaeeeeetaeees A 68 BGP 3 Specific Announce Policy Parameters ccccceeeeeeeneeeeeeeeeeeteeeeeeeeees A 70 BGP 4 Specific Announce Policy Parameters cccccsccecseeeeeeeeeeeeeeeeeeaeeeeeeeees A 74 Appendix B Converting Cisco to Nortel Networks Equivalents Gonfiguration Command Equivalents seisuses i aaa i B 1 Interpreting the Configuration
79. with the lower autonomous system number becomes active the other becomes the passive router Table 8 1 shows all possible acquisition mode combinations that are available when you configure the EGP neighbors at each end of a connection However Nortel Networks recommends that one router be configured in the active acquisition mode and the other in the passive acquisition mode 308628 15 0 Rev 00 8 3 Configuring IP Exterior Gateway Protocols BGP and EGP In the neighbor reachability phase EGP is responsible for monitoring and maintaining an established EGP neighbor relationship between two routers Its purpose is to ensure that the neighbors are operational and can provide reliable network reachability information Two neighbors will be able to exchange network reachability information only if they are both in the up state and know that they are both in the up state This is the point at which neighbor reachability is positively determined In the network reachability phase EGP is responsible for determining which networks are reachable through two EGP neighbors that is it provides the network reachability information This information provides a list of gateways the networks those gateways can reach and their associated distances Two neighbors determine network reachability by exchanging poll messages and routing update responses as follows e The active neighbor sends a poll message to a passive neighbor that i
80. you want to disable BGP 4 for the entire router 1 3 6 1 4 1 18 3 5 3 2 5 3 1 2 BGP Peer Parameters Parameter Path Default Options Function Instructions MIB Object ID Peer Address Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers gt Add None Any IP address Specifies the IP address of the interface on the remote side of this BGP peer connection Enter the IP address in dotted decimal notation If the peer is in a remote AS the address must be on the same subnet as the local interface 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 6 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Peer AS Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers None 1 to 65535 Identifies the autonomous system to which the BGP router at the remote end of this BGP peer connection belongs Enter the appropriate AS number 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 10 Local Address Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers gt Add None Any IP address Specifies the IP address of the interface on the local side of this BGP peer connection Enter the appropriate address 1 3 6 1
81. 1 18 3 5 3 2 6 5 1 5 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 7 1 5 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 9 1 5 308628 15 0 Rev 00 A 31 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Action Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies EGP Accept BGP 3 BGP 4 Ignore Accept Ignore Specifies whether the protocol ignores a route that matches the policy or forwards the route to the routing table manager Specify Accept to consider the route for insertion in the routing table To drop the route specify Ignore EGP 1 3 6 1 4 1 18 3 5 3 2 6 5 1 6 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 7 1 6 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 9 1 6 A 32 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters Route Preference Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies Configuration Manager gt Protocols
82. 15 0 Rev 00 Configuring Route and Traffic Balancing Now consider that BGP on router F receives advertisements to three destinations destination_1 destination_2 and destination_3 from its peer on router A For each of these destinations BGP consults the IP routing table to determine the next OSPF hop If you configure BGP on router F for IBGP ECMP route balancing BGP submits one BGP route to the routing table for each BGP destination using in round robin fashion the available OSPF ECMP routes as follows 1 BGP submits a route to destination_1 and specifies interface 1 the interface to router D as the next hop 2 BGP submits a route to destination_2 and specifies interface 4 the interface to router C as the next hop 3 BGP submits a BGP route to destination_3 and specifies interface 1 as the next hop Figure 7 2 shows the three route balancing BGP ECMP entries to the routing table on router F Destination Mask Proto Age Cost Next Hop AS destination_1 BGP 4 577438 126992 F 1 764 destination_2 BGP 4 577438 126992 F 4 764 destination_3 BGP 4 577438 126992 F 1 764 Figure 7 2 IBGP ECMP Route Balancing If you configure BGP for traffic balancing BGP submits multiple BGP routes one for each OSPF ECMP route as follows 1 BGP submits two IP routes to destination_1 One route specifies interface 1 the second route specifies interface 4 2 BGP submits two IP routes to destination_2 One route specifies interface 1 t
83. 18 3 5 3 2 6 7 1 9 A 36 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Peer AS Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies An empty list A list of autonomous system numbers 1 through 65 535 Specifies one or more autonomous systems This policy applies to BGP advertisements from peers in those ASs Use the default empty list to indicate that this policy applies to BGP advertisements from peers in any AS 1 3 6 1 4 1 18 3 5 3 2 6 7 1 10 Peer Address Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies An empty list A list of IP addresses Specifies one or more BGP peers This policy applies to BGP advertisements from the peers on this list To indicate that this policy applies to BGP advertisements from any BGP peer use the default empty list 1 3 6 1 4 1 18 3 5 3 2 6 7 1 11 Originating AS Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies An empty list A list of autonomous system numbers Specifies one or more autonomous systems This policy applies to BGP advertisements that originate from the ASs on this list To indicate
84. 23 leitiatizing TOF wih the MDS QT sicctcccctcnuetciccnntetcceecsbreaserasrndicaceandededaunidie tonnes 4 24 Generating MD5 Signatures on Transmitted BGP TCP Packets csccceee 4 24 Verifying MD5 Signatures on Received BGP TCP Packets cccecsssseeeeeeestees 4 25 Configuring BAP 4 Authentication oc cccssetccnedueisecevesetecces akin ane iaai 4 25 Chapter 5 Configuring BGP Accept and Announce Policies Conigurind a BGP Accept POlCY ccssecisctecicesicteionededa aia aaia anna Aa 5 2 Specifying Match Criteria for a BGP Accept Policy ccceecceccseeeeeeeeeeseeeeeeeneeeeees 5 6 Supplying Modification Values for a BGP Accept Policy c ssceeeeeeesteeeneees 5 10 Contig ring a BGF Announces PONY iesarkana easar aaa 5 13 Announce Policy Guidelines seisvet aaiae ai a aia 5 13 Specifying Match Criteria for a BGP Announce Policy c ccceceeeeeeeteeteeeeeeees 5 16 Supplying Modification Values fora BGP Announce Policy sccceeesesteeeeeeees 5 22 Configuring BGP 4 AS Path Pattern Matching cccccsssceeeeeeeseeeeeeaeeceeeeeeenaeeesenes 5 27 308628 15 0 Rev 00 vii Chapter 6 Configuring a Route Reflector Configuring a Single Route Reflector in an AS sirisser 6 3 Configuring a Route Reflector Cl Stet ssucisnidssirsin anaa a 6 5 Coniguring Multiple RR Clusters in an AS ssccuisscccssoscsesncsiasccnasenacsscosesissensentatedecearvleaines 6 7 Gongur ngan RE GBIU aaia a A an reerrT rrr e
85. 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the Route with MED parameter Click on Help or see the parameter description on page A 9 6 Click on OK You return to the Configuration Manager window Configuring BGP 4 Confederations If this router is a member of an autonomous system that is a confederation of sub ASs you can configure the confederation ID You can also specify the list of this BGP speaker s peers in other sub ASs within the same confederation If the confederation ID is not configured nil this AS is not a member of any confederation If the list of confederation peers is empty nil no peers to this speaker exist among the neighbor ASs that are members of this confederation You can use the BCC or Site Manager to configure BGP 4 confederations 308628 15 0 Rev 00 3 21 Configuring IP Exterior Gateway Protocols BGP and EGP Using the BCC Figure 3 1 shows an example of a BGP 4 confederation In this example the following steps establish sub ASs 65000 and 65001 as confederation peers 1 Specify sub AS 65002 as the local AS number and the external visible AS number 20 as the BGP confederation identifier by entering bgp local as 65002 bgp confederation id 20 Specify the local AS numbers of the other sub ASs within the same confederation as confederation peers by entering bgp confederation peers 65000 65001 Specify BGP peers within the
86. 7 4 Identifier parameter BGP 2 3 A 3 implementation notes BGP 1 12 EGP 8 5 inject time command 3 10 interior gateway protocol IGP 1 3 IP starting 2 3 K keepalive command BGP peer 4 8 Keepalive Timer parameter 4 9 A 15 L Local Address parameter BGP peer 2 4 A 12 in peer to peer session definition 4 3 Local AS parameter BGP 2 3 A 3 Local AS to Advertise to Peer parameter 4 14 A 16 local AS BGP changing 3 5 overriding the default in advertisements to peer 4 14 Local Autonomous System ID parameter 2 6 8 7 A 25 Local Pref Calculation parameter 3 28 A 9 local preference attribute calculating 3 25 local pref calculation command 3 28 loop detection disabling and reenabling 4 20 308628 15 0 Rev 00 match criteria accept policy 5 6 announce policy 5 16 Max BGP Version parameter 4 7 A 13 max update size command 4 15 max version command 4 6 MD5 Tcp Authentication BGP parameter A 18 Tcp Md5 Key BGP parameter A 20 Tcp Md5 Key Storage BGP parameter A 19 MED multiexit discriminator path attribute BGP setting in accept policies 5 10 Message Level parameter 3 30 A 24 message logging BGP 3 29 Message Trace Switch parameter 3 30 A 24 Min AS Origination Interval parameter 4 13 A 16 Min BGP Version parameter 4 7 A 13 min originate time command 4 12 min version command 4 6 modification values accept policy 5 10 announce policy 5 22 multihop con
87. 83 647 Specifies the minimum time interval in seconds between injections of external BGP routes into the IP routing table Accept the default or enter a nonzero value 1 3 6 1 4 1 18 3 5 3 2 5 1 1 10 308628 15 0 Rev 00 A 5 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Max Redundant Routes Configuration Manager gt Protocols gt IP gt BGP gt BGP Global 255 0 to 255 Specifies the maximum number of IBGP routes to the same destination to be stored At least one route is stored even if 0 is specified Accept the default value 255 or enter an integer from 1 through 255 1 3 6 1 4 1 18 3 5 3 2 5 1 1 14 Detect Redundant Connections Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Enable Enable Disable Specifies whether redundant BGP connections to the same router will be detected and disallowed Collision detection that is detecting the existence of redundant connections is based on router ID If two BGP peers have multiple physical connections and want to establish a BGP session across each physical connection you must disable this parameter The advantage of a configuration with multiple physical connections is redundancy The disadvantage is that such a configuration results in multiple copies of each route
88. 8628 15 0 Rev 00 6 3 Configuring IP Exterior Gateway Protocols BGP and EGP Using Site Manager To configure an IBGP speaker as a route reflector complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on Add The BGP Peer window opens 8 Set the following parameters Peer Address Peer AS e Local Address Click on Help or see the parameter descriptions beginning on page A 11 9 Set the Peer Mode parameter to Reflector Internal 10 Click on OK You return to the BGP Peer List window 11 Click on Apply and then click on Done You return to the IP Interface List for BGP window 6 4 308628 15 0 Rev 00 Configuring a Route Reflector Configuring a Route Reflector Cluster You can connect multiple route reflectors in a route reflector cluster Within a cluster IBGP route reflectors must be connected in a full mesh topology To configure a route reflector in a cluster you establish a peer to peer session with one or more route reflectors in the same cluster You can do this with the BCC or S
89. 9 1 16 A 42 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters BGP 4 Preference Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies 1 1 to 16 Specifies a value that can be used to compare a route that matches this policy with other BGP 4 routes The larger the value the greater the preference To indicate maximum preference enter 16 This parameter is valid only if the Action parameter is set to Accept 1 3 6 1 4 1 18 3 5 3 2 6 9 1 17 AS Weight Class Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies Class 1 Class 1 to Class 8 Indicates which weight class value should be used when calculating the AS path weight Enter a valid BGP 4 weight class This parameter is valid only if the Action parameter is set to Accept 1 3 6 1 4 1 18 3 5 3 2 6 9 1 18 AS Pattern Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies Empty string Any regular expression or empty string Allows AS_PATH pattern matching Enter a valid regular expression to indicate an AS and its position in a path The policy applies to all routes whose AS path inclu
90. BGP peer parameters System responds 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to edit parameters The parameters for that peer appear in the window Set the Next Hop Self parameter Click on Help or see the parameter description on page A 18 Click on Apply and then click on Done You return to the IP Interface List for BGP window Setting the Route Echo Switch The peer route echo switch controls the way that the router echoes a BGP route that is chosen for forwarding Echoing in this case means advertising the route back to the peer from which it was received By default the router advertises the route back as unreachable However you can configure the router to advertise the route back as reachable and to include the local AS You can use the BCC or Site Manager to set the peer route echo switch 308628 15 0 Rev 00 Using the BCC Configuring BGP Peers To set the peer route echo switch go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter route echo lt state gt state is either enabled or disabled default For example the following command causes BGP to echo a route as unreachable peer 2 2 2 2 2 2 2 5 route echo enabled peer 2 2 2 2 2 2 2 5 Using Site Manager To set the peer route echo switch complete the following steps Site Manager Procedure You do this Syst
91. BGP routes are accepted and announced by default and then put into the IP routing table e Nortel Networks After peering to a neighbor is established all incoming BGP routes are ignored by default and are not put into IP routing table e No BGP routes are advertised by default Directly connected interfaces and static routes are advertised in the BGP context when the BGP announce policy action parameter is set to announce and all other parameters are set to default values B 10 308628 15 0 Rev 00 Converting Cisco to Nortel Networks Equivalents Comparing BGP Route Selection Processes Table B 3 compares the Cisco and Nortel Networks path or best route selection processes In this table the most preferable criteria are higher in the table Table B 3 Route Selection Process Comparison Cisco BGP Path Selection Nortel Networks BGP Best Route Calculation for Equal Routes al 2 3 10 If the path specifies an inaccessible next hop drop the update Prefer the path with the largest weight If the weights are the same prefer the path with the largest local preference If the local preferences are the same prefer the path originated by BGP running on the router If no route was originated prefer the route with the shortest AS path If all paths have the same AS path length prefer the path with the lowest origin type where IGP is lower than EGP and EGP is lower than Incomplete If the origin code
92. BayRS Version 15 0 Part No 308628 15 0 Rev 00 June 2001 600 Technology Park Drive Billerica MA 01821 4130 Configuring IP Exterior Gateway Protocols BGP and EGP NORTEL NETWORKS Copyright 2001 Nortel Networks All rights reserved June 2001 The information in this document is subject to change without notice The statements configurations technical data and recommendations in this document are believed to be accurate and reliable but are presented without express or implied warranty Users must take full responsibility for their applications of any products specified in this document The information in this document is proprietary to Nortel Networks Inc The software described in this document is furnished under a license agreement and may only be used in accordance with the terms of that license The software license agreement is included in this document Trademarks Nortel Networks the Nortel Networks logo the Globemark Unified Networks AN ARN ASN BayRS BCC and Passport are trademarks of Nortel Networks Adobe and Acrobat Reader are trademarks of Adobe Systems Incorporated Ethernet is a trademark of Xerox Corporation Restricted Rights Legend Use duplication or disclosure by the United States Government is subject to restrictions as set forth in subparagraph c 1 ii of the Rights in Technical Data and Computer Software clause at DFARS 252 227 7013 Notwithstanding any other license agreement that
93. Command Equivalents Table cccceeeceeseeteeeeeee B 6 Comparing the Operational Comings sicccsioccissccdscasinesscivtnecteiesosmncnaccteaedecateunaatetannes B 8 Interpreting the Operational Commands Table ccceccececeeeeeeeeeeeeeeeeeeeeeseeeeeeeeeeee B 9 Comparing BGP Route Selection Processes cc ccssnesseccsesaneessaneeeenesenseeesaaee B 11 Regular Expression SYDOR airando niaaa ALa aa E B 12 Nortel Networks AS Path Pattern Matching Symbols c ccceeceeeseeeeeeeeeeeteeeteaees B 13 Index 308628 15 0 Rev 00 ix Figures Figure 1 1 Internetwork Segmented into Three Autonomous Systems 0 08 1 2 Figure 1 2 BGP Connecting Two Autonomous Systems Running OSPF 0 1 4 PRU TS TARGA cadicasncascccsassecasaceteedohcetsanteddcadantecsindsiendcncthadepaicacdaepedacadaumeackateners 1 7 Figure Si BGP Gomecerallot rivininirmir imania oir aie 3 23 Figure 4 1 Establishing and Confirming a Connection Between BGP Peers 4 4 Figure 4 2 BGP over an Unnumbered Point to Point Link essees 4 21 Figure 6 1 IBGP Single Route Reflector Topology c sccesceeeseeseeeeeeeeeeeeeeeeeenees 6 2 Figure 7 1 PBGPIOSPF A tonomo s Systemi sccsccussiscccascccetsesccsescceticsesneersvonteceeigarnees 7 2 Figure 7 2 IBGP ECMP Route Balancing oiicssccsccciasd peers onid nnna 7 3 Figure 3s IBGP EOMP Talie Balanbihg csiccisiemrcdnaentormnstbid ee 7 4 Foue 7 4 ECMPF Sifati FOUS sa
94. Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Specific Inter AS Metric Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Null Null or an AS metric Specifies a value for the inter AS metric Supply a value and set the Inter AS Metric Selector parameter to Specified 1 3 6 1 4 1 18 3 5 3 2 6 8 1 25 Origin Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies As Is As Is IGP EGP Incomplete Specifies an Origin attribute override The Origin attribute of a route matching this policy will be replaced with the indicated value To allow the existing Origin attribute use the default 1 3 6 1 4 1 18 3 5 3 2 6 8 1 26 AS Path Override Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies An empty list A list of AS numbers Specifies an AS path override Enter a non null value to override the AS path attribute of a route matching this policy Each element of the AS path is an AS number Valid only if the Action parameter is set to Announce Use the default empty list to allow the existing AS path attribute to remain in the route 1 3 6 1 4 1 18 3 5 3 2 6 8 1 27 A 72 308628 15 0 Rev 00 Parameter
95. EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Rule Precedence Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies 0 A metric value Specifies a metric value to be used to compare this policy with other policies that a route may match A policy with a higher metric takes precedence over a policy with a lower metric In case of a tie the protocol uses an internal index value assigned to the policy by IP software In general the index value is indicated by the position of the policy in the Site Manager display the last policy in the display has the highest index value Use this parameter to assign precedence to policies that match the same route EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 7 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 7 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 7 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters Route Source Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy F
96. GP The following conditions must apply The local BGP router and the remote BGP router must be connected by multiple links IP must be configured on a circuitless virtual interface on both the local and remote routers The EBGP speaker on the local router and the EBGP speaker on the remote router must establish a peer to peer session using their circuitless virtual IP interfaces For information see Chapter 4 Configuring BGP Peers The local IP routing table must contain multiple equal cost routes to the circuitless interface of the router in the remote AS These ECMP routes are typically submitted statically but they could also be submitted by OSPF or RIP In Figure 7 4 for example two BGP routers located in different ASs are connected by two physical links ae Local AS a ae ee a et ee cc Peer to Peer Session IP circuitless interface aks 6 ate es a eee Remote AS m W Q U Si ee fees Sah R Sy Key ECMP static routes IP0090B Figure 7 4 ECMP Static Routes 7 6 308628 15 0 Rev 00 Configuring Route and Traffic Balancing Assume that the IP routing table on the BGP router in the local AS contains two ECMP static routes to the circuitless virtual interface of the BGP router in the remote AS One ECMP route uses interface 1 the other route uses interface 2 Assume also that the two EBGP speakers have established a p
97. GP Accept and Announce Policies BCC Match Parameters for BGP Announce Policies continued Values Function network List of IP addresses Specifies which networks will match this policy Each identifier consists of a network number a mask and a flag to indicate whether the address refers to a specific network or to a range of networks Enter a specific encoding of 0 0 0 0 0 0 0 0 exact to match the default route Enter a range encoding of 0 0 0 0 0 0 0 0 range to match any route Use the default empty list to match any route next hop List of IP addresses Specifies one or more IP addresses This policy applies to BGP advertisements whose Next Hop attribute matches an IP address on this list and applies only to BGP sourced routes when BGP is included as a route source ospf router id List of IP addresses Specifies the IDs of one or more OSPF routers This policy applies to OSPF advertisements authored by a router on this list and applies only to OSPF sourced routes when OSPF is included as a route source ospf tag List of OSPF ASE tag values Specifies tag values that could be present in an OSPF ASE advertisement This policy applies to OSPF ASE advertisements that contain tag values in this list and applies only to OSPF sourced ASE routes when OSPF is included as a route source outbound as List of AS numbers Specifies a list of AS numbers If an AS number is included in th
98. IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to The parameters for that peer appear in edit parameters the window 8 Set the Holdtime parameter Click on Help or see the parameter description on page A 15 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window Setting a Minimum AS Origination Interval By default a BGP speaker that issues an update to advertise a change in the AS must wait at least 15 seconds before advertising a subsequent change You can use the BCC or Site Manager to specify a different interval Using the BCC To specify a different interval go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter min originate time lt seconds gt seconds is an integer from 1 through 2 147 483 647 indicating the minimum number of seconds that BGP waits between advertisements 4 12 308628 15 0 Rev 00 Configuring BGP Peers For example the following command causes BGP to wait at least 30 seconds between updates on the peer session established between interfaces 2 2 2 2 and 2 2 2 5 peer 2 2 2 2 2 2 2 5 min originate time 30 peer 2 2 2 2 2 2 2 5 Using Site Manager
99. IVE AGREEMENT BETWEEN NORTEL NETWORKS AND LICENSEE WHICH SUPERSEDES ALL PRIOR ORAL AND WRITTEN AGREEMENTS AND COMMUNICATIONS BETWEEN THE PARTIES PERTAINING TO THE SUBJECT MATTER OF THIS AGREEMENT NO DIFFERENT OR ADDITIONAL TERMS WILL BE ENFORCEABLE AGAINST NORTEL NETWORKS UNLESS NORTEL NETWORKS GIVES ITS EXPRESS WRITTEN CONSENT INCLUDING AN EXPRESS WAIVER OF THE TERMS OF THIS AGREEMENT iv 308628 15 0 Rev 00 Contents Preface ede wh LEM Ets 1 eon r a cern E T E L entre Teen renner E E T nna ttt on XV PERG RINGS E E E E E E E E E E xvi PETE aiban E E ET E A AEA xviii Fae UU INS E A A A E N A EAA XX Fon TE GEV HEI irarri oa a aie erie ee xxi Chapter 1 Exterior Gateway Protocols BGP and EGP Autonomous Systems and Gateway Protocols cccccceceeeeseeeceeeeeeeaeeeeeeeeesaaeeesenees 1 1 Boner Gateway Protocol BGP sccxsses iisinetassaataat ania enamels 1 3 Bxtenor Gateway Protocol EAP ercomisisonse iarsa aieiai EAEE 1 3 Classless Vite rc rina FORING issia caaan reds a e 1 4 BGP Conceps and Ter iia ay enirintan NA ANN 1 4 Pearni Poor eS NS cicocecisirceact ccsuacacs ccievdewess cealdiwasy eseukente nme adeteaees ene Sateen 1 5 Stub and Multihomed Autonomous Systems cccccceeesceeeeeeeceeaeeeeeneeeeeaeeeeeaeeeeees 1 6 menor BOF ROUN sarginis a i aaa SASS 1 6 BOF Rons RoR 01 Le euie N 1 7 Egiak oat MUNDA Mepeererecrnererrrecrer ere ertrcrern Srerrren AE 1 8 BGFP UPONNEET ane rete cement ar tenet erence
100. P Global The current BGP Local AS value 1 to 65535 Identifies the autonomous system to which this BGP router belongs Either accept the current BGP Local AS value or enter a new value for this parameter 1 3 6 1 4 1 18 3 5 3 2 5 1 1 5 A 4 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters BGP Intra AS Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Enable Enable Disable Specifies whether BGP will perform intra AS IBGP routing Transit ASs should use intra AS routing Stub or multihomed ASs usually do not use IBGP intra AS routing 1 3 6 1 4 1 18 3 5 3 2 5 1 1 8 BGP From Protocols Configuration Manager gt Protocols gt IP gt BGP gt BGP Global BGP BGP All Controls if intra AS routing is enabled the types of routes that BGP advertises in any IBGP sessions Select BGP to propagate only advertised routes learned from external BGP peers Select All to propagate routes learned from all route sources excluding IBGP and OSPF interarea and intra area routes which are never advertised with IBGP 1 3 6 1 4 1 18 3 5 3 2 5 1 1 9 BGP Interval Timer Configuration Manager gt Protocols gt IP gt BGP gt BGP Global 5 seconds 1 to 2 147 4
101. Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on Add The BGP Peer window opens 8 Set the following parameters Peer Address Peer AS e Local Address Click on Help or see the parameter descriptions beginning on page A 11 9 Set the Peer Mode parameter to Reflector Internal 10 Click on OK You return to the BGP Peer List window 11 Click on Apply and then click on Done You return to the IP Interface List for BGP window 6 6 308628 15 0 Rev 00 Configuring a Route Reflector Configuring Multiple RR Clusters in an AS An AS can contain multiple IBGP route reflector clusters In an AS with multiple clusters e Each cluster has a unique ID e Within each cluster RR clients are connected to RRs in a tree topology e Within the AS clusters are connected in arbitrary topologies From the point of view of the topology a cluster is a mini AS Like an AS a cluster can be configured in an arbitrary way To configure multiple RR clusters in an AS complete the following steps 1 Associate a route reflector with a cluster 2 Establish a peer to peer session with a reflector in another cluster Using the BCC To associate a route reflector with a clust
102. RIP and OSPF Services Configuring IBGP for Route and Traffic Balancing To configure an IBGP speaker for route balancing and traffic balancing the IGP used in the AS OSPF for example should be configured for ECMP on all routers An IBGP speaker must be configured for ECMP on OSPF BGP routers For instructions on configuring ECMP see Configuring IP ARP RARP RIP and OSPF Services Figure 7 1 shows an AS containing six IP routers The routers with interfaces to internal links only are running OSPF The routers with interfaces to both internal and external links are running OSPF and BGP 308628 15 0 Rev 00 7 1 Configuring IP Exterior Gateway Protocols BGP and EGP Key ECMP OSPF routes from router F to router A IP0089B Figure 7 1 BGP OSPF Autonomous System Assume for this example that OSPF is configured throughout the AS to support ECMP routes and that all links in the AS have the same cost This means that the IP routing table on router F includes two ECMP routes to router A One route uses interface 1 the other route uses interface 4 Assume as well that the BGP speakers on routers A B and F have established a full mesh of IBGP peer to peer sessions with each other using routers C D and E 7 2 308628
103. Site Manager For more information about using the Technician Interface to access the MIB see Using Technician Interface Software Caution The Technician Interface does not verify the validity of your parameter values Entering an invalid value can corrupt your configuration BGP Parameters Topic Page BGP Configuration Parameters A 3 BGP Global Parameters A 4 BGP 3 Global Parameter A 11 BGP 4 Global Parameter A 11 BGP Peer Parameters A 11 BGP AS Weight and Weight Class Parameters A 20 BGP Event Message Parameters A 24 A 2 308628 15 0 Rev 00 Site Manager Parameters BGP Configuration Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Identifier Choose BGP in the Select Protocols window None An IP address of an IP interface on this router Identifies the BGP router There is no default for this parameter You must use an IP address of one of the router s IP interfaces Either accept the current BGP identifier or enter a new IP address The BGP identifier must be one of the router s IP interfaces If both BGP and OSPF are running on the router then the BGP and OSPF router IDs must be set to the same IP interface 1 3 6 1 4 1 18 3 5 3 2 5 1 1 4 Local AS Select BGP in the Select Protocols window None 1 to 65535 Identifies t
104. Specifying the lowest precedence value for this policy ensures that this policy is always the last policy to be used when there are multiple matching policies If your network includes routers from vendors other than Nortel Networks when you configure announce policies make sure that the network list has at least one entry Otherwise announcements will be made to all routers which may cause routing problems for BGP configurations on routers supplied by vendors that do not implement the extended AS field correctly To optimize the use of announce policies we recommend that you use contiguous blocks of addresses in network lists and that the network list for each policy contains the largest contiguous block of addresses possible 308628 15 0 Rev 00 5 13 Configuring IP Exterior Gateway Protocols BGP and EGP Using the BCC To create a BGP announce policy go to the BGP prompt for example box ip bgp and enter announce lt policy_name gt policy_name is a unique name for the BGP announce policy For example the following command creates a BGP announce policy named pol_1 bgp announce pol_1 announce pol_1 bgp To customize the default policy parameters enter lt parameter gt lt value gt Table 5 4 lists the parameters and values that you can enter Table 5 4 BCC Definition Parameters for BGP Announce Policies Parameter Values Function action ignore default Specifies whether or not to advertise a route t
105. Text BCC Command Site Manager Logical Steps 6 neighbor 1 1 1 1 route map ip bgp Protocols gt IP gt Policy Filters gt BGP 4 gt setASPath out announce setASPath Announce Policies gt Add foute map setASPath action announce modify Name setASPath permit 10 as path prepend 123 123 Action ANNOUNCE set as path prepend 123 back As Prepend 123 123 123 match outbound peer 1 1 1 1 Peer Address 1 1 1 1 7 neighbor 1 1 1 1 route map ip bgp Protocols gt IP gt Policy Filters gt BGP 4 gt AdvertiseMap out announce AdvertiseMap Announce Policies gt Add foute map action announce Name AdvertiseMap AdvertiseMap permit 10 precedence 2 match Action ANNOUNCE match ip address 1 network 192 10 20 0 Network List gt List set metric 100 255 255 255 0 range back Network Number 192 10 20 0 route map outbound peer 1 1 1 1 Network Mask 255 255 255 0 AdvertiseMap permit 20 back back Match Criteria range set metric 50 modify Multi Exit Discriminator Specified access list 1 permit med method specified Multi Exit Discriminator Value 100 192 10 20 0 0 0 0 255 med 100 Rule Precedence 2 Outbound Peers 1 1 1 1 ip bgp announce AdvertiseMapOther Protocols gt IP gt Policy Filters gt BGP 4 gt action announce Announce Policies gt Add precedence 1 modify Name AdvertiseMapOther med method specified Action ANNOUNCE med 50 Multi Exit Discriminator Specified match outbound peer 1 1 1 1 Multi Exit Discriminator Value 50 Rule Precedence 1 Outbound Peers 1 1 1 1 8 ip
106. The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the Black Hole Routes parameter Click on Help or see the parameter description on page A 8 6 Click on OK You return to the Configuration Manager window Disabling and Reenabling the BGP 4 MED Attribute By default BGP 4 considers the multiexit discriminator MED path attribute in the route selection process see Table 1 3 on page 1 10 You can use the BCC or Site Manager to configure BGP 4 so that it disregards the MED attribute in the route selection process Using the BCC To configure BGP 4 to disregard the MED attribute in the route selection process go to the BGP prompt for example box ip bgp and enter med comparison lt state gt state is either enabled default or disabled For example the following command causes BGP 4 to disregard the MED attribute in an update when selecting a route bgp med comparison disabled bgp 3 20 308628 15 0 Rev 00 Using Site Manager Configuring Global BGP Parameters To configure BGP 4 to disregard the MED attribute in the route selection process complete the following steps You do this Site Manager Procedure System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens
107. a route in the UPDATE message has traversed 1 3 6 1 4 1 18 3 5 3 2 6 10 1 27 Local Preference Override Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies False False True Indicates whether or not you are supplying an override value for the Local Preference path attribute in the routing update message The Local Pref attribute is valid only in an update advertised to an IBGP peer If you select False the router uses the IP route weight value to calculate the LOCAL_PREF path attribute To override the Local Preference attribute select True and supply a value for the Local Preference Value parameter 1 3 6 1 4 1 18 3 5 3 2 6 10 1 28 308628 15 0 Rev 00 A 77 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Local Preference Override Value Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies Null Null or a route weight value Specifies an override value for the Local Preference attribute Enter a value and set the Local Preference Override parameter to True 1 3 6 1 4 1 18 3 5 3 2 6 10 1 29 Override Next Hop Configuration Manager gt Protocols gt IP gt Policy Filters
108. ability information not just updates The router uses this information to maintain a list of gateways the networks the gateways can reach and the corresponding distances Chapter 8 Customizing EGP Services describes the use of EGP 308628 15 0 Rev 00 1 3 Configuring IP Exterior Gateway Protocols BGP and EGP Classless Interdomain Routing Classless interdomain routing CIDR is an addressing scheme that uses supernet addresses to represent multiple IP destinations Rather than advertise a separate route for each destination network in a supernet a router uses a supernet address to advertise a single route called an aggregate route that represents all the destinations CIDR reduces the size of the routing tables used to store advertised IP routes BGP 4 supports classless interdomain routing BGP Concepts and Terminology BGP is an exterior gateway protocol designed to exchange network reachability information with other BGP systems in other autonomous systems or within the same autonomous system Figure 1 2 shows two autonomous systems AS1 and AS2 Networks within AS1 and AS2 are connected by routers running an interior gateway protocol in this case OSPF The two ASs are connected by routers that run an exterior gateway protocol B GP in addition to OSPF AS1 AS2 Exterior BGP connection
109. ager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of IP addresses Specifies one or more BGP peers This policy applies to BGP advertisements from the peers on this list To indicate that this policy applies to BGP advertisements from any BGP peer use the default empty list 1 3 6 1 4 1 18 3 5 3 2 6 9 1 11 Originating AS Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of autonomous system numbers Specifies one or more autonomous systems This policy applies to BGP advertisements that originate from the ASs on this list To indicate that the policy applies to BGP advertisements originating from any AS use the default empty list 1 3 6 1 4 1 18 3 5 3 2 6 9 1 12 Route Origin Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies Any Any IGP EGP IGP or EGP Incomplete Incomplete Orig IGP Incomplete Orig EGP Specifies which values of the BGP origin attribute apply to this policy Select the origin values that you want to accept for this policy 1 3 6 1 4 1 18 3 5 3 2 6 9 1 13 308628 15 0 Rev 00 A 41 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Pa
110. aker forms a neighbor relationship with another BGP speaker by establishing a peer to peer session See Chapter 4 Configuring BGP Peers 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Stub and Multihomed Autonomous Systems An AS can include one or more BGP speakers that establish peer to peer sessions with BGP speakers in other autonomous systems to provide external route information for the networks within the AS A multihomed AS has multiple BGP speakers A stub AS has a single BGP speaker that establishes a peer to peer session with one external BGP speaker The BGP speaker provides external route information only for the networks contained within its own AS Interior BGP Routing Nortel Networks implements interior BGP IBGP intra AS routing With IBGP each router in the AS runs an interior gateway protocol IGP such as OSPF for internal routing updates and also maintains an IBGP connection to each BGP border router The IBGP information along with the IGP route to the originating BGP border router determines the next hop to use for external networks Some IGPs carry no BGP information However an OSPF type 5 LSA can carry BGP specific information in its tag field Each router uses IBGP exclusively to determine reachability to external networks When an IBGP update for a network is received it is passed to IP for inclusion in the routing table only if a viable IGP route to the correct
111. alue 2 Configuration Manager gt Protocols gt IP gt BGP gt Weights 8 1 to 15 plus the infinity value of 16 Specifies the class 2 weight value to add to this AS This weight value is added to the other AS weight values in a route to determine the preference of the route and aid in route selection Either accept the current AS weight value or enter a new value Any route that traverses an AS with an AS weight of 16 infinity will not be used 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 5 Weight Value 3 Configuration Manager gt Protocols gt IP gt BGP gt Weights 8 1 to 15 plus the infinity value of 16 Specifies the class 3 weight value to add to this AS This weight value is added to the other AS weight values in a route to determine the preference of the route and aid in route selection Either accept the current AS weight value or enter a new value Any route that traverses an AS with an AS weight of 16 infinity will not be used 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 5 Weight Value 4 Configuration Manager gt Protocols gt IP gt BGP gt Weights 8 1 to 15 plus the infinity value of 16 Specifies the class 4 weight value to add to this AS This weight value is added to the other AS weight values in a route to determine the preference of the route and aid in route selection Either accept the current AS weight value or enter a new value Any route that traverses an AS with an AS weight of 16 infinity will not be used
112. an AS all BGP speakers should use the same method to determine local preference and to select the best routes Note For a comparison of the Nortel Networks and Cisco route selection processes see Comparing BGP Route Selection Processes on page B 11 If you are configuring BGP in a network that also includes routers from vendors other than Nortel Networks you can disable BayRS local preference calculation and route selection Instead BGP assigns a value of 100 to externally received routes and uses the rules listed in Table 3 4 on page 3 27 for best route selection Calculating BGP 4 Local Preference Values BGP 4 update messages contain a local preference value that an AS border router can assign to a route when advertising it to IBGP peers The calculation of the local preference attribute is specific to each implementation A higher value indicates that the route is more preferred The router uses the following equation to calculate a value for the local preference attribute local_preference 8191 origin_value AS_path_weight origin_value is 0 for routes with an origin path attribute of IGP or 4096 for other routes 308628 15 0 Rev 00 3 25 Configuring IP Exterior Gateway Protocols BGP and EGP AS_path_weight is a sum of weight values associated with AS numbers listed in the route s AS Path attribute These weight values can be configured and default to 8 For information about configuring AS path weights
113. ancing or traffic load balancing To configure IBGP to use IGP ECMP routes for route balancing set this parameter to Route Balance To configure IBGP to use IGP ECMP routes for traffic load balancing set this parameter to Traffic Balance 1 3 6 1 4 1 18 3 5 3 2 5 1 1 26 Local Pref Calculation Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Enabled Enabled Disabled Disables BayRS local preference calculation of received EBGP routes Set this parameter as required 1 3 6 1 4 1 18 3 5 3 2 5 1 1 27 308628 15 0 Rev 00 A 9 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Confederation ID Configuration Manager gt Protocols gt IP gt BGP gt BGP Global 0 0 to 65535 Specifies the BGP confederation identifier for this router Set this parameter to the confederation identifier of this router Specify a value of 0 if this autonomous system AS is not a member of any confederation 1 3 6 1 4 1 18 3 5 3 2 5 1 1 28 Confederation Peer Configuration Manager gt Protocols gt IP gt BGP gt BGP Global List The peer list of this BGP speaker to other member sub ASs within the same confederation If this value is unavailable nil
114. and EGP For example the following command sequence configures the router to log BGP warning fault and trace messages for open and keepalive packets for a peer connection and then disables message logging peer 2 2 2 2 2 2 2 4 debug control debug control 2 2 2 2 2 2 2 4 log message type warning fault trace debug control 2 2 2 2 2 2 2 4 log packet type open keepalive debug control 2 2 2 2 2 2 2 4 log packet type disabled debug control 2 2 2 2 2 2 2 4 back peer 2 2 2 2 2 2 2 4 2 2 2 2 Using Site Manager To configure BGP event message logging complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP DEBUG The BGP DEBUG Parameters window opens 5 Click on Add The NEW BGP DEBUG window opens 6 Set the following parameters Peer Local Remote Message Level Message Trace Switch Click on Help or see the parameter descriptions beginning on page A 24 7 Click on OK You return to the BGP DEBUG Parameters window 8 Click on Apply and then click on Done You return to the Configuration Manager window 3 30 308628 15 0 Rev 00 Configuring Global BGP Parameters Configuring EBGP Route Flap Damping The frequent change of network reachability information that can be c
115. and OSPF Services By default BGP implements a TTL value as follows e IBGP peers use the TTL value set for global IP BGP enforces the one hop rule for EBGP peers that is the remote peer must be located on a directly attached network If you enable multihop connections for EBGP peers EBGP peers also use the TTL value set for global IP see Enabling Multihop Connections on page 3 13 You can specify a TTL value for a BGP session that overrides the TTL value set for IP To specify a TTL value for a BGP peer connection go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter ttl lt hops gt hops is the time to live value expressed as the number of hops from 1 through 255 that BGP inserts in outbound updates sent on this peer session The default value is 0 to use the same TTL value set for global IP For example the following command sequence enables multihop connections for all EBGP peers configures a session with a remote peer in AS 5 and causes BGP to insert a TTL value of 4 in each outbound update sent over the peer connection bgp multi hop enabled bgp peer local 2 2 2 2 remote 3 3 3 3 as 5 peer 2 2 2 2 3 3 3 3 ttlh4 peer 2 2 2 2 3 3 3 3 4 16 308628 15 0 Rev 00 Configuring BGP Peers Specifying the Next Hop Router A BGP update message has a path attribute called NEXT_HOP that specifies the IP address of the router to use as the next hop for the advertised destinations
116. and propagate all routes Make consistent routing policy decisions on external BGP connections To configure BGP and download full Internet routes on the Passport 5430 Multiservice Access Switch you must install the router with 64 MB of memory 308628 15 0 Rev 00 Chapter 2 Starting BGP and EGP Services This chapter describes how to use the BCC and Site Manager to start BGP services using default values and how to use Site Manager to start EGP services using default values It also describes how to use Site Manager to delete BGP and EGP services Topic Page Starting BGP with the BCC 2 1 Starting IP and BGP with Site Manager 2 3 Starting IP and EGP with Site Manager 2 6 Starting BGP with the BCC To start BGP using the BCC 1 Configure BGP on the router 2 Define a BGP peer to peer connection Note Before you configure BGP 4 see BGP Implementation Notes on page 1 12 for information Step 1 Configuring Global BGP To configure BGP on the router go to the global IP prompt for example box ip and enter bgp router id lt router_id gt 308628 15 0 Rev 00 2 1 Configuring IP Exterior Gateway Protocols BGP and EGP router_idis the BGP router ID expressed as an octet string The router ID typically is a circuitless IP interface used by BGP to communicate with other BGP routers If the router is also running OSPF the BGP ID must match the OSPF ID For example
117. atches the AS pattern ending with X for example 99_ matches 99 199 23299 308628 15 0 Rev 00 A accept policies creating 5 2 specifying match criteria 5 6 supplying modification values 5 10 acquisition mode for EGP neighbors 8 11 Acquisition Mode parameter 8 11 A 27 acronyms xviii advertise time command 4 9 aggregate route definition 1 4 announce policies creating 5 13 policy guidelines 5 13 specifying match criteria 5 16 supplying modification values 5 22 AS parameter 3 38 A 20 AS path pattern matching 5 17 5 27 AS weights for BGP assigning 3 37 AS local BGP setting 3 5 AS transit 1 6 authentication MD5 configuring 4 22 described 1 11 autonomous system AS definition 1 1 best route selection Cisco and Nortel Networks methods B 11 BGP accept policies See accept policies announce policies See announce policies AS weight classes assigning 3 37 best route calculation 3 25 3 27 configuring and customizing 3 1 308628 15 0 Rev 00 Index configuring as a soloist 3 16 deleting from the router 2 4 disabling and reenabling 3 2 dynamic policy configuration disabling 3 15 EBGP route and traffic load balancing 7 5 frequency of Keepalive messages for 4 8 holddown time for peers 4 11 IBGP route and traffic load balancing 7 1 implementation notes 1 12 interaction with OSPF and RIP enabling 3 9 interior BGP IBGP 1 6 local AS managing 3 5 lo
118. ateNets Announce Policies gt Add summary only action announce match Name AggregateNets network 195 89 8 0 Action ANNOUNCE 255 255 248 0 range back back Network List 195 89 8 0 modify advertise 195 89 8 0 255 255 248 0 range 255 255 248 0 Advertise List 195 89 8 0 255 255 248 0 13 router ospf 101 ip ospf as boundary router true OSPF AS Boundary Router YES redistribute bgp 2000 ip bgp intra as routing disabled Intra AS Disabled 14 router bgp 2000 ip bgp Announce Policy Name redistribute ospf 101 announce RedistributeOSPFtoBGP redistribute static RedistributeOSPFtoBGP Action ANNOUNCE action announce match Route Source OSPF STATIC protocol source ospf static 15 timers bgp 60 180 ip bgp Protocols gt IP gt BGP gt Peers peer 1 1 1 1 1 1 1 2 BGP Peers as 333 Keepalive Timer 60 keepalive 60 Holdtime 180 holddown 180 16 interface loopbackO virtual ip 1 1 1 1 255 255 255 255 Protocols gt IP gt Circuitless IP gt Create ip address 1 1 1 1 IP Address 1 1 1 1 255 255 255 255 Subnet Mask 255 255 255 255 17 ip subnet zero ip all subnets enabled Protocols gt IP gt Global Zero Subnet Enable 18 router bgp 4001 ip bgp Protocols gt IP gt BGP gt BGP Global Bgp confederation local as 5 BGP Local AS 5 identifier 5 confederation id 4001 Confederation ID 4001 bgp confederation peers confederation peers 4002 4003 Confederation Peer gt List 4002 4003 4004 4004 Autonomous System 4002 4003 neighbor 1 2 3 4 peer 1 2 3 1 1 2 3 4 as 4002 4004 rem
119. ault To specify the maximum version go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter max version lt version gt version is either bgp3 or bgp4 default 4 6 308628 15 0 Rev 00 Using Site Manager Configuring BGP Peers To specify the minimum and maximum version of BGP complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to edit parameters 8 Set the following parameters Min BGP Version Max BGP Version Click on Help or see the parameter descriptions starting on page A 13 The parameters for that peer appear in the window 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Keeping the Connection Alive After a session is established BGP peers periodically issue keepalive messages to maintain the connection By default BGP issues a keepalive message every 30 seconds Yo
120. aused by an unstable route is commonly referred to as route flap Route flap damping is a technique for suppressing information about unstable routes When configuring the damping of unstable EBGP routes the route flap damping mechanism performs the following functions e Determines the stability of an EBGP route e Suppresses the use and advertisement of unstable EBGP routes e Unsuppresses a route that has regained stability To determine the stability of a route in the IP routing table BGP maintains a penalty value for the route based on its recent history Each time the route flaps that is each time it is withdrawn from the routing table BGP increments this penalty value During the period of time that the route does not flap BGP decrements the penalty value In this way as the instability of the route increases the penalty value rises As the route becomes more stable the penalty value falls To monitor BGP for route flaps you set the route damping parameter on a BGP accept policy that matches the route BGP creates a penalty value for the route and sets the value to 0 BGP increments the penalty value each time that the route flaps BGP provides a route flap damping template that allows you to control the way BGP evaluates a route s penalty and how based on the penalty it decides to suppress or unsuppress the route The template consists of the following parameters e Cutoff threshold If the penalty value rises above the
121. cal preference attribute 3 25 maximum update size for 4 15 message logging 3 29 3 30 minimum AS origination interval for 4 12 negotiating the version 4 6 next hop setting 4 17 overriding the local AS number 4 14 path attributes 1 9 peers configuring 4 1 peers configuring over unnumbered point to point link 4 21 redundant connections enabling and disabling 3 12 route echo switch enabling 4 19 route reflector 1 7 6 1 router ID 3 4 RR client 6 10 setting timer for injecting external BGP routes into routing table 3 10 TTL time to live specifying 4 16 BGP Dynamic Policy Change Support parameter 3 15 A 7 BGP Enable parameter 3 3 A 4 BGP From Protocols parameter 3 8 3 10 A 5 BGP Identifier parameter 3 5 A 4 BGP Interval Timer parameter 3 11 A 5 Index 1 BGP Intra AS parameter 3 7 A 5 BGP Local AS parameter 3 6 A 4 BGP Soloist Slots parameter 3 17 A 7 BGP OSPF interaction 1 10 3 9 black hole punching 3 18 black hole routes definition 3 18 Border Gateway Protocol BGP See BGP C Cisco BGP path selection and Nortel Networks equivalent B 11 Cisco commands and Nortel Networks equivalents B 1 Cisco regular expressions B 12 Confederation ID parameter 3 24 A 10 Confederation Peer parameter 3 24 A 10 confederations BGP configuring 3 21 described 1 11 Connect Retry Timer parameter 4 5 A 14 conventions text xvi customer support xxi customizing BGP 3 1 D
122. click on OK The IP Configuration window opens Set the following parameters IP Address Subnet Mask Transmit Beast Addr UnNumbered Assoc Address Click on Help or see the parameter description in Configuring IP ARP RARP RIP and OSPF Services 3 Click on OK The EGP Configuration window opens Set the following parameters Local Autonomous System ID decimal Remote Peer IP Address Gateway Mode Click on Help or see the parameter descriptions beginning on page A 25 Click on OK Site Manager enables EGP service and returns you to the Configuration Manager window 2 6 308628 15 0 Rev 00 Starting BGP and EGP Services The instructions in this chapter show you how to start EGP using default values For information about modifying EGP default values see Chapter 8 Customizing EGP Services Deleting EGP from the Router You can delete EGP from all router circuits on which it is currently enabled To delete EGP complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP 3 Choose EGP The IP menu opens The EGP menu opens 4 Choose Delete EGP Site Manager asks you to confirm the deletion of EGP 5 Click on OK Site Manager removes EGP from all circuits on the router and retu
123. cols BGP and EGP For example the following command sets the external advertisement timer to 20 seconds for the peer session established between interfaces 2 2 2 2 and 2 2 2 5 peer 2 2 2 2 2 2 2 5 advertise time 20 peer 2 2 2 2 2 2 2 5 Using Site Manager To specify a value for the external advertisement timer complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to edit parameters The parameters for that peer appear in the window 8 Set the External Advertisement Timer parameter Click on Help or see the parameter description on page A 14 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window 308628 15 0 Rev 00 Configuring BGP Peers Specifying a Holddown Time The holddown time is the amount of time that either peer waits for a keepalive or update message before declaring the connection down A BGP speaker that initiates a connection inserts a holddown time value into the open message The peer
124. communities in the update Specify a List of BGP well known community name no export communities no advertise no export subconfed or enter a four octet community number in the form AS_number value Entering 0 in the two most significant bits causes the router to match on the lower 16 bits advertise List of IP addresses Specifies a list of networks that BGP advertises instead of the networks in the routing table If you supply a list that includes the encoding 255 255 255 255 255 255 255 255 the actual network IDs are advertised along with the other IDs in the advertise list This allows advertisement of an aggregate or default route along with the actual network If the actual network is a subnet and the advertising protocol supports subnet advertisements the subnet is advertised This item is a BCC object with parameters of its own To specify multiple items create multiple objects 5 24 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies For example the following command sequence configures the router to advertise network 192 10 20 0 255 255 255 0 and sets the MED to 100 announce pol_1 bgp action announce announce pol_1 bgp modify modify bgp announce pol_1 advertise 192 10 20 0 24 advertise 192 10 20 0 255 255 255 0 bgp announce pol_1 back modify bgp announce pol_1 med method specified modify bgp announce pol_1 med 100 modify bgp announce pol_1 Using Site Manager To sup
125. configuration Site Manager Procedure You do this System responds alk In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP 4 Choose BGP Global The BGP menu opens The Edit BGP Global Parameters window opens Set the BGP Dynamic Policy Change Support parameter Click on Help or see the parameter description on page A 7 Click on OK You return to the Configuration Manager window 308628 15 0 Rev 00 3 15 Configuring IP Exterior Gateway Protocols BGP and EGP Configuring the BGP Soloist Slot Mask By default BGP runs as a soloist on a slot determined by the BGP soloist slot mask Nortel Networks recommends that the slot mask include only nonforwarding slots so that BGP operations route calculation for example occur on one slot while the other slots maintain maximum forwarding capability If the slot on which the soloist is running fails BGP runs on an eligible slot By default BGP considers all slots with IP interfaces to be eligible slots You can use the BCC or Site Manager to specify one or more slots for the BGP soloist Using the BCC To configure the BGP slot mask go to the BGP prompt for example box ip bgp and enter slot mask lt s ot gt slot is one of the values listed in Table 3 2 To include more than one slot enclose the slot numbers in braces
126. contact the Nortel Networks Technical Solutions Center A steep penalty is applied to routes that are advertised with an origin attribute other than IGP or incomplete For an OSPF internal route or a direct route the local preference attribute is set to local_preference 8191 256 metric 255 metric is the OSPF metric for an OSPF route or the configured cost for a direct route For a RIP route an EGP route an OSPF ASE route or a static route the local preference attribute is set to local_preference 256 metric metric is the RIP metric for a RIP route the EGP metric for an EGP route the OSPF metric for an OSPF ASE route or the configured cost for a static route Local preference values for OSPF internal routes and direct routes are higher than the local preference values calculated for BGP routes 3 26 308628 15 0 Rev 00 Best Route Selection Table 3 4 Configuring Global BGP Parameters BGP uses the rules in Table 3 4 as tie breakers to select the best BGP route This table lists the rules in the order in which they are evaluated Best Route Selection Rules 1 2 3 ON 10 Default Preference Tiebreaker Rules local pref calculation enabled Choose the route with the lower route weight Choose the route with the higher local preference attribute Choose the route with the shortest AS path Choose the route with the smallest ORIGIN IGP lt EGP lt INCOMPLETE Cho
127. ct ID Name Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies None Any alphanumeric character string Identifies this accept policy Specify a name for the policy EGP 1 3 6 1 4 1 18 3 5 3 2 6 5 1 4 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 7 1 4 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 9 1 4 A 30 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters Networks Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of network identifiers Each entry consists of a network number a mask and a flag to indicate whether the ID refers to a specific network or a range of networks Specifies the networks to which this policy applies Enter a specific encoding of 0 0 0 0 0 0 0 0 to match the default route Enter a range encoding of 0 0 0 0 0 0 0 0 to match any route Use the default empty list to match any route EGP 1 3 6 1 4
128. ction on each router Configuring and Enabling MD5 Authentication BGP 4 TCP MD5 authentication lets you configure BGP peers to ensure secure message interchange BGP 4 TCP MD5 message authentication provides the following features e A TCP MDS signature can exist for BGP peers e You can configure authentication and secret keys on a per peer basis Peers configured with common secret keys can authenticate each other and exchange routing information e Configurations can concurrently have BGP peers with authentication enabled and authentication disabled e You can store keys as either clear text or encrypted and you can set this storage mode on a per peer basis 4 22 308628 15 0 Rev 00 Configuring BGP Peers When you enable BGP 4 TCP MD5 authentication the router computes an MD5 signature for each TCP packet based on the TCP packet and a per peer secret key The router adds this MDS signature to the TCP packet containing a BGP message and sends it with the packet but it does not send the secret key The receiver of the TCP packet also knows the secret key and can verify the MD5 signature A third party trying to masquerade as the sender however cannot generate an authentic signature because it does not know the secret key The per peer secret keys provide the security If the keys are compromised for example by transfer of the configuration file then the authentication itself is compromised To prevent this the secr
129. ctors e Forwards best route advertisements to RR clients and other reflectors You configure an IBGP speaker to be a route reflector or RR client and establish peer to peer connections between reflectors and clients as described in the following topics Topic Page Configuring a Single Route Reflector in an AS 6 3 Configuring a Route Reflector Cluster 6 5 Configuring Multiple RR Clusters in an AS 6 7 Configuring an RR Client 6 10 Note When you configure a session between two IBGP route reflectors or between an RR and an RR client you must configure both ends of the session 308628 15 0 Rev 00 6 1 Configuring IP Exterior Gateway Protocols BGP and EGP Figure 6 1 for example shows an AS with a single route reflector connected to five IBGP speakers configured as RR clients The RR receives a route advertisement from RR client 1 determines that the route is the best route to the external destination and forwards the route to RR clients 2 3 4 and 5 Se e RR client 2 RR client 1 ys Route reflector ra y RR client 5 l TJ RR client3 lt q _ gt RR client 4 Autonomous system Key Peer to peer session BGP route advertisement IP0065B Figure 6 1 IBGP Single Route Reflector To
130. data or information without first obtaining any required export licenses or other governmental approvals Without limiting the foregoing Licensee on behalf of itself and its subsidiaries and affiliates agrees that it will not without first obtaining all export licenses and approvals required by the U S Government i export re export transfer or divert any such Software or technical data or any direct product thereof to any country to which such exports or re exports are restricted or embargoed under United States export control laws and regulations or to any national or resident of such restricted or embargoed countries or ii provide the Software or related technical data or information to any military end user or for any military end use including the design development or production of any chemical nuclear or biological weapons 9 General If any provision of this Agreement is held to be invalid or unenforceable by a court of competent jurisdiction the remainder of the provisions of this Agreement shall remain in full force and effect This Agreement will be governed by the laws of the state of California Should you have any questions concerning this Agreement contact Nortel Networks Inc 2375 N Glenville Dr Richardson TX 75082 LICENSEE ACKNOWLEDGES THAT LICENSEE HAS READ THIS AGREEMENT UNDERSTANDS IT AND AGREES TO BE BOUND BY ITS TERMS AND CONDITIONS LICENSEE FURTHER AGREES THAT THIS AGREEMENT IS THE ENTIRE AND EXCLUS
131. des the AS in that position For example the expression 200 means that the policy applies to all routes whose AS_PATH attribute contains AS 200 as the last AS in the path 1 3 6 1 4 1 18 3 5 3 2 6 9 1 19 308628 15 0 Rev 00 A 43 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID BGP Communities to Match Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of BGP communities Specifies one or more BGP communities This policy applies to all BGP advertisements that match the list Supply an octet string using the following format each community ID is 4 bytes long 0 in the two most significant bits causes the router to perform the match on the lower 16 bits the default empty list means match any list 1 3 6 1 4 1 18 3 5 3 2 6 9 1 20 AS Prepend Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of autonomous systems Specifies one or more AS numbers to be added as a SEQUENCE to AS Path Supply an octet string containing AS numbers to be added as a SEQUENCE to AS Path 1 3 6 1 4 1 18 3 5 3 2 6 9 1 23 BGP Community to acce
132. dresses Specifies the IP address of one or more BGP peers If a BGP peer is included in this list this policy applies to BGP advertisements being sent to that peer Specify one or more IP addresses Configure an empty list to indicate that this policy applies to BGP advertisements being sent to any peer 1 3 6 1 4 1 18 3 5 3 2 6 10 1 23 Multi Exit Discriminator Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies None None Specified Originating Indicates whether or not a multiexit discriminator metric is to be advertised for a network matching this policy and if advertised what value to use Select None to indicate that no value is to be advertised Select Specified to indicate that the value you specify for the Multi Exit Discriminator Value parameter is to be used Select Originating to indicate that the metric from the originating protocol is to be used This parameter is valid only if the Action parameter is set to Announce 1 3 6 1 4 1 18 3 5 3 2 6 10 1 24 308628 15 0 Rev 00 A 75 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Multi Exit Discriminator Value Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies Null Null or a metric value Speci
133. e same route EGP 1 3 6 1 4 1 18 3 5 3 2 6 5 1 8 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 7 1 8 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 9 1 8 EGP Specific Accept Policy Parameters Parameter Path Default Options Function Instructions MIB Object ID Peer List Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies An empty list A list of IP addresses Specifies the IP addresses of one or more EGP peers This policy applies to EGP advertisements from the peers on this list Use the default empty list to indicate that this policy applies to EGP advertisements from any EGP peer 1 3 6 1 4 1 18 3 5 3 2 6 5 1 10 A 34 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters AS List Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies An empty list A list of autonomous system numbers Specifies one or more autonomous system numbers This policy applies to EGP advertisements from peers located in the autonomous systems on this list Use the default empty list to indicate that this policy applies to EGP advertisements from peers in any AS 1 3 6 1 4 1 18 3 5 3 2 6 5 1 11 Gateway List Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies An em
134. e 201 1 1 4 255 255 255 252 192 32 28 51 back 7 8 308628 15 0 Rev 00 ip bgp bgp router id 201 1 1 1 bgp local as 11 bgp multi hop enabled bgp peer 201 1 1 1 201 1 1 4 as 12 Configuring Route and Traffic Balancing peer 201 1 1 1 201 1 1 4 ebgp ecmp method route balance peer 201 1 1 1 201 1 1 4 back bgp Using Site Manager To configure EBGP ECMP for route or traffic balancing complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers 7 Click on the peer for which you want to edit parameters The BGP Peer List window opens The parameters for that peer appear in the window 8 Set the Peer EBGP ECMP Method parameter Click on Help or see the parameter description on page A 18 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window 10 Click on Done You return to the Configuration Manager window 308628 15 0 Rev 00 Chapter 8 Customizing EGP Services This chapter explains how to configure the Exterior Gateway Protocol EGP
135. e Delete BGP 3 Site Manager asks you to confirm the deletion of BGP 3 5 Click on OK Site Manager removes BGP 3 from all circuits on the router and returns you to the Configuration Manager window To delete BGP 4 using Site Manager complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Delete BGP 4 Site Manager asks you to confirm the deletion of BGP 4 5 Click on OK Site Manager removes BGP 4 from all circuits on the router and returns you to the Configuration Manager window 308628 15 0 Rev 00 2 5 Configuring IP Exterior Gateway Protocols BGP and EGP Starting IP and EGP with Site Manager Before you can select a protocol to run on the router you must configure a circuit that the protocol can use as an interface to an attached network For information and instructions see Configuring WAN Line Services and Configuring Ethernet FDDI and Token Ring Services After you configure the circuit you can access the Site Manager Select Protocols window To start IP and EGP from the Select Protocols window complete the following steps You do this Site Manager Procedure System responds 1 In the Select Protocols window select the following protocols IP EGP Then
136. e IP to return an ICMP destination unreachable message to the sender of a packet that best matches the black hole route 3 18 308628 15 0 Rev 00 Using the BCC Configuring Global BGP Parameters To enable or disable black hole punching go to the BGP prompt for example box ip bgp and enter black hole punching lt action gt action is one of the values described in Table 3 3 Table 3 3 Value Black Hole Punching Parameter Settings Meaning disabled default drop reject Disables black hole punching Enables black hole punching IP drops packets for the black hole route destination without returning an ICMP message to the sender Enables black hole punching IP drops packets for the black hole route destination and returns an ICMP destination unreachable message to the sender For example the following command causes BGP to submit aggregate routes to the routing table as black hole routes IP drops packets for the black hole route but does not return ICMP destination unreachable messages to the sender bgp black hole punching drop bgp 308628 15 0 Rev 00 3 19 Configuring IP Exterior Gateway Protocols BGP and EGP Using Site Manager To enable or disable black hole punching complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP
137. e Policy Filters The Policy Filters menu opens ay eo Choose BGP 4 Choose Accept Policies The BGP 4 menu opens The BGP4 Accept Policy Filters window opens Click on the accept policy to which you want to apply route flap damping The parameter values for that policy appear in the window Set the following parameters BGP Route Flap Dampening BGP Route Flap Dampening Template Click on Help or see the parameter descriptions beginning on page A 45 Note The BGP Route Flap Dampening Template parameter is grayed out unless the BGP Route Flap Dampening parameter is set to ENABLE Click on Apply and then click on Done You return to the Configuration Manager window 3 36 308628 15 0 Rev 00 Configuring Global BGP Parameters Assigning Weight Classes and Values to an AS You can assign a weight class to any AS number and a weight value to a weight class Weights provide a way either to prefer or to avoid routes that pass through certain ASs The weights of each AS in a path are added and the path with the smallest total weight is the preferred path An assigned weight can range from 1 through 15 plus an infinity value Any path containing an AS weight of infinity is avoided AS weight classes allow you to assign multiple weight values to the same AS This feature allows you to consider an AS path differently for different networks For example consider a situation in which
138. e maximum size in bytes of update messages that are sent to this peer Accept the default or specify a size If the size of the update message that advertises a single route is greater than the configured message size the actual message size can exceed the configured value 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 32 A 16 308628 15 0 Rev 00 Site Manager Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Peer Route Echo Switch Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers Disabled Enabled Disabled Controls the way the router echoes a BGP route that is selected for forwarding Echoing in this case means advertising the route back to the peer from which it was received If this parameter is enabled the router advertises the route back as reachable and includes the local AS If this parameter is disabled the router echoes the route as unreachable withdrawn A BGP speaker that participates in inter AS multicast routing must advertise a route it receives from one of its external peers If the router stores the route in its routing table it must also advertise it back to the peer from which the route was received If the peer router saves routes that contain its own AS number and is running short of memory send an unreachable echo 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 33 Loo
139. ecifies a list of IP addresses of EGP peers If a peer appears in this list the policy applies to EGP advertisements sent to that peer Specify one or more IP addresses Use the default empty list to indicate that the policy applies to any EGP peer 1 3 6 1 4 1 18 3 5 3 2 6 6 1 22 A 68 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters EGP Interface List Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies An empty list A list of IP addresses Specifies a list of outgoing interfaces If an interface appears on this list the policy applies to EGP advertisements sent via that interface Specify one or more IP addresses Use the default empty list to indicate that this policy applies to any outbound interface 1 3 6 1 4 1 18 3 5 3 2 6 6 1 23 EGP Metric Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies 0 0 or an export metric value Specifies an optional export metric to use when advertising a route that matches this policy Select the default to indicate that the routing table metric calculated for EGP is to be used This parameter is valid only if the Action parameter is set to Announce 1 3 6 1 4 1 18 3 5 3 2 6 6 1 24 308628 15 0 Rev 00 Configuring IP Exterior
140. ed or is destined for a network within its AS Core When the router is configured as a core gateway the AS to which it belongs acts as a transit AS In core mode the router can advertise and forward traffic to networks that are reachable inside or outside its local AS If you choose noncore mode the AS to which this EGP neighbor belongs will act as a stub AS That is it will advertise only networks that reside within the AS The default gateway mode is core mode If the EGP router is reconfigured to run in noncore mode Site Manager automatically configures EGP export route filters on that IP interface This action suppresses OSPF external routes to EGP and the advertisement of any networks learned by EGP To specify the gateway mode of this EGP neighbor complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens edit 2 Choose IP The IP menu opens 3 Choose EGP The EGP menu opens 4 Choose Neighbors The IP Interface List for EGP window opens 5 Click on the IP interface that you want to The parameter values for that interface appear in the window 6 Click on EGP Neighbor The EGP Neighbors List window opens 7 Click on the address of the EGP neighbor that you want to edit The parameter values for that neighbor appear in the window Set the Gateway Mode para
141. eeceeeeeeeeeeeeeeseaeeeeaeeeseeaeeesaeeeaees 3 37 vi 308628 15 0 Rev 00 Chapter 4 Configuring BGP Peers Defining a Peerto Poer GOSS cccccicsc scasctassvinnned song daseeasaddanegucnecobivdeinqradnieiomduedaswaceuvens 4 2 Initiating a Peer to Peer SESSION srciinroirrnniti niiret aridin arand A NN NANEN NNE ENNEN 4 4 Negoiaung he BGP Yarsion cirnsdneninenen e e 4 6 PRS UAV Me Conneccion AINE siistiminen aata a iai 4 8 Setting the External Advertisement Timer cccceesececeeeeeeeaeeeeeeeeeeaaeeeeeeeeeeaeeeteneeee 4 9 Speciiying 2 FROIN TME ssis crenata e E EA 4 11 Setting a Minimum AS Origination Interval ccccceceeseeeeeceeeeeeeseaaeseeeeeeseeaeessaeeneenes 4 12 QOvemding the Local AS NUmMDET avossi ssscinsssiiad uiisvandecutinindsanmssedeaa dies aaa aa 4 14 SOSH ines a Maximum Update IZ sjaicsirnareijs naiari iaae 4 14 Speciymg a Tmeto Live Vae sinciera tirin aa AANA 4 16 Speciying the NextHop ROUTE gccssccccavicsctnnciecaucssaduacgensnsavausntpeuaacaeinendaacteoneioraonaaets 4 17 Getin the Route Echo GWI seein apinn RA 4 18 Disabling and Reenabling Loop Detection 2 cc ccccseecsccceetnecnseeneeecedeesneceeceneeent 4 20 Configuring Peers over an Unnumbered Point to Point Link c cccseeeeeeeeeesteeeeeees 4 21 Ganfiguring and Enabling MDS Authentication iis sescccceasdents vececscarsantesseeeesecnieets 4 22 Entering and Storing MD5 Authentication Keys cccsceeseeeeeeeeeeeeeeeeseteeeeaeeeeaes 4
142. eer to peer session using their circuitless virtual IP interfaces Now assume that the local EBGP speaker has received from its remote peer advertisements for routes to three destinations destination_1 destination_2 and destination_3 If you configure the local EBGP speaker for ECMP route balancing BGP submits one BGP route to the routing table for each BGP destination using in turn round robin the available ECMP routes as follows 1 BGP submits a BGP route to destination_1 and specifies interface 1 as the next hop 2 BGP submits a BGP route to destination_2 and specifies interface 2 as the next hop 3 BGP submits a BGP route to destination_3 and specifies interface 1 as the next hop If you configure EBGP for traffic balancing BGP submits multiple BGP routes one for each static ECMP route as follows 1 BGP submits two IP routes to destination_1 One route specifies interface 1 the second route specifies interface 2 2 BGP submits two IP routes to destination_2 One route specifies interface 1 the second route specifies interface 2 3 BGP submits two IP routes to destination_3 One route specifies interface 1 the second route specifies interface 2 You can use the BCC or Site Manager to configure EBGP ECMP for route and traffic balancing 308628 15 0 Rev 00 7 7 Configuring IP Exterior Gateway Protocols BGP and EGP Using the BCC To configure EBGP ECMP for route balancing or traffic balancing go
143. em responds 1 Inthe Configuration Manager window choose Protocols 2 Choose IP The Protocols menu opens The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to edit parameters The parameters for that peer appear in the window 8 Set the Peer Route Echo Switch parameter Click on Help or see the parameter description on page A 17 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window 308628 15 0 Rev 00 4 19 Configuring IP Exterior Gateway Protocols BGP and EGP Disabling and Reenabling Loop Detection By default BGP resets a peer to peer session if it discovers a loop in the AS path You can use the BCC or Site Manager to disable and reenable loop detection Using the BCC To disable or reenable loop detection go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter detect as loop lt state gt state is either enabled default or disabled For example the following command disables loop detection on peer to peer session 2 2 2 2 2 2 2 4 peer 2 2 2 2 2 2 2 4 detect as loop disabled peer 2 2 2 2 2 2 2 4 Using Site Manager To disable or
144. equired 1 3 6 1 4 1 18 3 5 3 2 5 1 1 22 Black Hole Routes Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Disabled Disabled Drop Reject Specifies whether BGP submits a black hole route to the routing table for an aggregate route advertised to a BGP peer To prevent BGP from submitting a black hole route to the IP routing table for a route advertised to a BGP peer set this parameter to Disabled To drop a packet for an unknown destination set this parameter to Drop To configure BGP to return an ICMP destination unreachable message to the sender set this parameter to Reject 1 3 6 1 4 1 18 3 5 3 2 5 1 1 23 A 8 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Route with MED Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Enable Enable Disable Specifies whether BGP considers the multiexit discriminator path attribute in the route selection process Set this parameter as required 1 3 6 1 4 1 18 3 5 3 2 5 1 1 24 IBGP ECMP Method Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Disabled Disabled Route Balance Traffic Balance Specifies whether IBGP uses ECMP paths provided by the IGP for route bal
145. er go to the BGP prompt for example box ip bgp and enter cluster id lt cluster_id gt cluster_id is the ID number from 0 through 4 294 967 295 of the cluster where the route reflector resides For example the following command associates the route reflector with cluster 5 bgp cluster id 5 bgp To establish a peer to peer session with a route reflector in another cluster go to the BGP prompt and enter peer local lt ocal_reflector_address gt remote lt remote_reflector_address gt as lt as_number gt local_reflector_address is the IP address on the local route reflector remote_reflector_address is the IP address on the remote reflector in another cluster as_numberis the AS where the remote reflector resides 308628 15 0 Rev 00 6 7 Configuring IP Exterior Gateway Protocols BGP and EGP At the session specific prompt enter the following command to specify that the remote peer is a route reflector in another cluster peer mode reflector external For example the following command sequence defines a peer to peer session between two route reflectors represented by addresses 2 2 2 2 and 2 2 2 3 located in different clusters in AS 2 bgp peer local 2 2 2 2 remote 2 2 2 3 as 2 peer 2 2 2 2 2 2 2 3 peer mode reflector external peer 2 2 2 2 2 2 2 3 Using Site Manager To establish a peer to peer session with a route reflector in another cluster complete the following steps Site Manager Pr
146. er is used between BGP peers as a periodic check of the TCP connection between them The holddown timer is the amount of elapsed time before the BGP peer session is declared dead RFC 1771 suggests values of 30 and 90 seconds respectively Nortel Networks suggests that the holddown timer be set to three times the amount of the keepalive timer The Cisco loopback interface and the Nortel Networks circuitless virtual IP interface are useful in BGP environments for peer interfaces Enable subnet zero for interface addresses and routing updates Enable confederations for IBGP full mesh reduction In this example the outside world sees a single AS number 5 but the AS is divided into autonomous systems 4001 4002 4003 and 4004 This router s confederation ID is 4001 It has a peer 1 2 3 4 within its routing confederation domain and another peer 3 4 5 6 outside Enables MD5 authentication on the TCP connection between the two BGP peers 132 245 10 1 and 132 245 10 2 In this example the MDS key is bla4u00 2nkq 308628 15 0 Rev 00 B 7 Configuring IP Exterior Gateway Protocols BGP and EGP Comparing the Operational Commands Table B 2 compares the corresponding operational commands for Cisco and the Nortel Networks BCC The numbered list following the table describes the commands in the correspondingly numbered table row Table B 2 Cisco and Nortel Networks BGP Operational Commands Item Cisco Nortel Ne
147. ers used in the Nortel Networks implementation of AS path pattern matching Table 5 7 Characters in AS Path Pattern Matching Symbol or Operator Meaning lt Denotes the beginning of an AS SEQUENCE segment gt Denotes the end of an AS SEQUENCE segment Denotes the beginning of an AS SET segment Denotes the end of an AS SET segment period Matches any single character including white space lt seq gt set Denotes an AS path containing a sequence in the first segment and a set in the second segment A Denotes the following pattern occurs at the beginning of the AS path Denotes the preceding pattern occurs at the end of the AS path Denotes logical OR match this or that X Matches exactly the AS specified by X X Matches the AS pattern beginning with X for example _99 matches 99 991 9934 X Matches the AS pattern ending with X for example 99_ matches 99 199 23299 308628 15 0 Rev 00 5 27 Chapter 6 Configuring a Route Reflector To avoid the resource cost of a full mesh topology to support IBGP speakers within a large AS you can configure a router to function as an IBGP route reflector RR An IBGP speaker that needs to communicate with other BGP speakers in the AS establishes a single peer to peer RR client session with the IBGP route reflector A route reflector does the following e Receives route advertisements from RR clients and other refle
148. ertisement Specify a non null value only if the Action parameter is set to Accept The values you enter in the injection list determine the action taken If you supply a list of network IDs or the default network ID 0 0 0 0 0 0 0 0 these IDs are injected into the routing table instead of the actual received IDs If you use the default value an empty list the actual received network IDs are injected into the routing table The Injection List parameter does not perform route aggregation as defined in RFC 1654 To aggregate routes in a transit AS you must construct an announce policy and use the announce Advertise parameter 1 3 6 1 4 1 18 3 5 3 2 6 9 1 9 Peer AS Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of autonomous system numbers 1 through 65 535 Specifies one or more ASs This policy applies to BGP advertisements from peers in the autonomous systems on this list Use the default empty list to indicate that this policy applies to BGP advertisements from peers in any AS 1 3 6 1 4 1 18 3 5 3 2 6 9 1 10 A 40 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Peer Address Configuration Man
149. et keys can be stored in encrypted form in the configuration file and the MIB using the Technician Interface secure shell to encrypt the per peer secret keys The secure shell uses DES to encrypt the secret keys and the DES key the NPK MEK is stored in the router s nonvolatile RAM NVRAM Use the Technician Interface secure shell to enter the message encryption key node protection key NPK MEK value before you set the MD5 authentication parameters For information about the Technician Interface secure shell see Configuring IPsec Services You can enter the authentication keys using the BCC or Site Manager Entering and Storing MD5 Authentication Keys To configure BGP TCP MD5 authentication set the wfB gpPeerTcpAuthentication MIB object to MDS You can then enter an optional variable length ASCII authentication key for each BGP 4 peer This key is stored in the wfBgpPeerTcpMd5Key MIB object Setting the authentication key also enables authentication for the peer connection Both peers must be configured with the same authentication key When an authentication key is stored in the MIB or the configuration file it can optionally be encrypted using DES with the NPK MEK key as selected by the wfBgpPeerTcpMd5KeyStorage MIB object 308628 15 0 Rev 00 4 23 Configuring IP Exterior Gateway Protocols BGP and EGP You can enter the authentication keys using the BCC or Site Manager Use the Technician Interface secure shell to enter t
150. eters for BGP Accept Policies Parameter Values Function action ignore default Specifies whether BGP ignores a route accept that matches the policy or forwards the route to the routing table manager as weight class bgp4 preference class1 default to class 8 1 default to 16 Indicates the weight class value to use when calculating the AS path weight Specifies a value used to compare a route that matches this policy with other BGP 4 routes The larger the value the greater the preference precedence 0 default to any positive integer Assigns a metric value to this policy a policy with a higher value takes precedence over a policy with a lower value This value determines the order of precedence for policies that match the same route preference 1 default to 16 Assigns a metric value the higher the number the greater the preference toa route that BGP forwards to the routing table manager If confronted with multiple routes to the same destination the routing table manager may use this value to decide which route to insert Routes for all networks 0 0 0 0 0 0 0 0 should have the lowest preference and routes for the most specific networks longest address and mask should have the highest preference route damping enabled disabled default Configures BGP to perform route flap damping on a route that matches this policy For instructions on configuring an accept policy for ro
151. faces 2 2 2 2 and 2 2 2 5 peer 2 2 2 2 2 2 2 5 max update size 950 peer 2 2 2 2 2 2 2 5 Using Site Manager To specify a maximum update size complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens want to edit BGP peer parameters 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to edit parameters The parameters for that peer appear in the window Set the Peer Max Update Size parameter Click on Help or see the parameter description on page A 16 Click on Apply and then click on Done You return to the IP Interface List for BGP window 308628 15 0 Rev 00 4 15 Configuring IP Exterior Gateway Protocols BGP and EGP Specifying a Time to Live Value Each IP data packet includes a time to live TTL value The TTL value specifies the maximum number of hops that the packet is allowed to traverse in the network before an intermediate router discards the packet The TTL counter prevents packets from looping endlessly through the network For instructions on setting the global IP TTL value see Configuring IP ARP RARP RIP
152. fies a metric for the multiexit discriminator attribute To advertise a multiexit discriminator value set the Action parameter to Announce and set the Multi Exit Discriminator parameter to Specified 1 3 6 1 4 1 18 3 5 3 2 6 10 1 25 Origin Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies None None IGP EGP Incomplete Specifies an Origin attribute override The Origin attribute of a route matching this policy will be replaced with the indicated value To allow the existing Origin attribute use the default 1 3 6 1 4 1 18 3 5 3 2 6 10 1 26 A 76 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Replace As Path Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies Null An AS path Specifies an AS path that overrides the AS path attribute of a route matching this policy Construct a BGP 4 AS path composed of AS path segments Each AS path segment includes a path segment type a path segment length specifying the number of ASs in the segment and a path segment value containing one or more AS numbers There are two AS path segment types type 1 an unordered set of ASs that a route in the UPDATE message has traversed and type 2 an ordered set of ASs that
153. fy is stored in the format specified by the Tcp Md5 Key Storage parameter Specify the value that you want to use for the MD5 authentication key 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 47 BGP AS Weight and Weight Class Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID AS Configuration Manager gt Protocols gt IP gt BGP gt Weights gt Add Null 1 to 65535 Identifies the autonomous system to which you want to assign a weight Enter the appropriate AS number 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 4 Weight Value 1 Configuration Manager gt Protocols gt IP gt BGP gt Weights 8 1 to 15 plus the infinity value of 16 Specifies the class 1 weight value to add to this AS This weight value is added to the other AS weight values in a route to determine the preference of the route and aid in route selection Either accept the current AS weight value or enter a new value Any route that traverses an AS with an AS weight of 16 infinity will not be used 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 5 A 20 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Weight V
154. ge has traversed and type 2 an ordered set of ASs that a route in the update message has traversed continued 5 22 308628 15 0 Rev 00 Table 5 6 Parameter Configuring BGP Accept and Announce Policies Values BCC Modification Parameters for BGP Announce Policies continued Function as path prepend null default List of AS numbers Specifies AS numbers that BGP adds to an AS path before it adds the current AS to the path atomic aggregate default default force ignore Allows control over the atomic path attribute By default the router automatically sets this attribute if it knows that certain networks in an aggregate range have not been included in an aggregate advertisement local pref override false default true Indicates whether you are supplying an override value for the local preference path attribute in the routing update message The local preference attribute is valid only in an update advertised to an IBGP peer If you select false the router uses the IP route weight value to calculate the local preference path attribute local preference 0 default route weight value Specifies an override value for the local preference attribute med 0 default to 65535 Specifies a metric for the multiexit discriminator attribute med method none default specified originating Indicates whether a multiexit discriminator metric is to
155. ghbor to neighbor relationship by specifying the IP address of the router that is to be the remote neighbor To supply the address of the remote neighbor complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose EGP The EGP menu opens 4 Choose Neighbors The IP Interface List for EGP window opens 5 Click on the IP interface for which you The parameter values for that interface want to specify the neighbor s address appear in the window 6 Click on EGP Neighbor The EGP Neighbors List window opens 7 Click on Add The EGP Neighbor window opens 8 Set the Remote Autonomous System IP Address parameter Click on Help or see the parameter description on page A 26 9 Click on OK You return to the EGP Neighbors List window 10 Click on Apply and then click on Done You return to the IP Interface List for EGP window 11 Click on Done You return to the Configuration Manager window 8 8 308628 15 0 Rev 00 Specifying the Gateway Mode Customizing EGP Services You can configure the EGP router to operate in one of two gateway modes for any given IP interface Noncore When the router is configured as a noncore gateway the AS to which it belongs acts as a stub AS It advertises and forwards only traffic that originat
156. gurations where BGP speakers reside on routers that have multiple network connections over multiple IP interfaces the typical case for IBGP speakers consider using the address of the router s circuitless virtual IP interface as the local peer address In this way you ensure that BGP is reachable as long as there is an active circuit on the router If the remote peer is located in a different AS from the local peer the remote address must be on the same subnet as the local address To override this restriction see Enabling Multihop Connections on page 3 13 If the local peer and the remote peer are located in the same AS BGP assumes that you are configuring an IBGP session and does not impose this restriction You can use the BCC or Site Manager to specify this information Using the BCC To define a peer to peer session go to the BGP prompt for example box ip bgp and enter peer local lt ocal_address gt remote lt remote_address gt as lt as_number gt local_address is the IP address of the local interface remote_address is the IP address of the remote interface as_number is the number of the AS in which the remote peer is located For example the following command defines a session with a remote peer in AS 5 The local IP interface is 2 2 2 2 The interface for the remote peer is 2 2 2 5 bgp peer local 2 2 2 2 remote 2 2 2 5 as 5 peer 2 2 2 2 2 2 2 54 4 2 308628 15 0 Rev 00 Configuring BGP
157. hat announce matches this policy precedence 0 default to any Specifies a metric value to be used to compare this metric value policy with other policies that a route may match A policy with a higher metric takes precedence over a policy with a lower metric In case of a tie the protocol uses an internal index value assigned to the policy by IP software state enabled default Enables or disables this policy disabled For example the following command sequence causes BGP to announce routes that match policy_2 and sets the precedence of this policy to 5 announce policy_2 bgp action announce announce policy_2 bgp precedence 5 announce policy_2 bgp 5 14 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies Using Site Manager To create a BGP announce policy complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose Policy Filters The Policy Filters menu opens 4 Choose BGP 4 The BGP 4 Policies menu opens 5 Choose Announce Policies The BGP4 Announce Policy Filters window opens 6 Click on Add The BGP4 Announce IP Policy Filter Configuration window opens 7 Set the following parameters Name Action Rule Precedence Click on Help or see the parameter descriptions beginning on
158. he NPK MEK The BCC Site Manager and secure shell interfaces accept and display the authentication keys as unencrypted character strings regardless of whether the underlying storage is clear or encrypted That is these interfaces can encrypt a key before saving it and decrypt it before displaying it They also handle the necessary conversion from character string to octet string The Technician Interface however displays a key just as it is stored in the MIB TCP monitors the authentication using the attribute wfTcpConnMd5Errors in the wfTcpConnEntry record Initializing TCP with the MD5 Option If an MD5 authentication key is configured for a BGP peer that has BGP authentication enabled then BGP reads the authentication key from the MIB decrypts it if necessary and passes the unencrypted authentication key to TCP If there is no NPK available to decrypt an encrypted authentication key BGP logs an event BGP TCP MD5 NPK No NPK configured Generating MD5 Signatures on Transmitted BGP TCP Packets A BGP peer calculates the MDS signature for a BGP message on the following elements e TCP pseudo header e TCP header excluding options e TCP segment data e TCP MDS authentication key If TCP receives an MD5 authentication key it reduces its maximum segment size MSS by 18 octets the length of the TCP MD5 option It also adds an MD5 signature to each transmitted packet The peer inserts the resulting 16 byte MD5 signature into the follo
159. he autonomous system to which this BGP router belongs Enter a value from 1 to 65 535 1 3 6 1 4 1 18 3 5 3 2 5 1 1 5 308628 15 0 Rev 00 A 3 Configuring IP Exterior Gateway Protocols BGP and EGP BGP Global Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID BGP Enable Configuration Manager gt Protocols gt IP gt BGP gt BGP Global Enable Enable Disable Globally enables or disables BGP on all router interfaces Set to Disable if you want to disable BGP for the entire router Set to Enable if you previously disabled BGP and now want to reenable it 1 3 6 1 4 1 18 3 5 3 2 5 1 1 2 BGP Identifier Configuration Manager gt Protocols gt IP gt BGP gt BGP Global None An IP address of an IP interface on this router Identifies the BGP router There is no default for this parameter You must use an IP address of one of the router s IP interfaces Either accept the current BGP identifier or enter a new IP address The BGP identifier must be one of the router s IP interfaces If both BGP and OSPF are running on the router then the BGP and OSPF router IDs must be set to the same IP interface 1 3 6 1 4 1 18 3 5 3 2 5 1 1 4 BGP Local AS Configuration Manager gt Protocols gt IP gt BGP gt BG
160. he second route specifies interface 4 3 BGP submits two IP routes to destination_3 One route specifies interface 1 the second route specifies interface 4 308628 15 0 Rev 00 7 3 Configuring IP Exterior Gateway Protocols BGP and EGP Figure 7 3 shows the six traffic balancing BGP ECMP entries to the routing table on router F Destination Mask Proto Age Cost Next Hop AS destination_1 BGP 4 577438 126992 F 1 764 destination_1 BGP 4 577438 126992 F 4 764 destination_2 BGP 4 577438 126992 F 1 764 destination_2 BGP 4 577438 126992 F 4 764 destination_3 BGP 4 577438 126992 F 1 764 destination_3 BGP 4 577438 126992 F 4 764 Figure 7 3 IBGP ECMP Traffic Balancing You can use the BCC or Site Manager to configure IBGP for ECMP route balancing and traffic balancing Using the BCC To configure IBGP for ECMP route or traffic balancing go to the BGP prompt for example box ip bgp and enter ibgp ecmp method lt method gt method is one of the values described in Table 7 1 Table 7 1 IBGP ECMP Methods Method Meaning route balance BGP submits one BGP route to the IP routing table for each BGP destination using in turn round robin the available IGP ECMP routes to the next hop traffic balance BGP submits multiple routes to IP using all known IGP ECMP next hops disabled default IBGP implements neither route nor traffic balancing For example the following command configures BGP for IBGP ECMP
161. ht class 8 Indicates which weight class should be used when calculating the AS path weight Set the Action parameter to Accept and supply a valid BGP 3 weight class 1 3 6 1 4 1 18 3 5 3 2 6 7 1 15 A 38 308628 15 0 Rev 00 Site Manager Parameters Parameter Path Default Options Function Instructions MIB Object ID BGP Communities to match Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies An empty list A list of BGP communities Specifies one or more BGP communities This policy applies to all BGP advertisements that match the list Supply an octet string using the following format each community ID is 4 bytes long 0 in the two most significant bits causes the router to perform the match on the lower 16 bits the default empty list means match any list 1 3 6 1 4 1 18 3 5 3 2 6 7 1 16 308628 15 0 Rev 00 A 39 Configuring IP Exterior Gateway Protocols BGP and EGP BGP 4 Specific Accept Policy Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Injection List Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of network identifiers Specifies network IDs to be included in the routing table in place of the network IDs listed in the received adv
162. ia has been damaged as a result of accident misuse or abuse The Licensee assumes all responsibility for selection of the Software to achieve Licensee s intended results and for the installation use and results obtained from the Software Nortel Networks does not warrant a that the functions contained in the software will meet the Licensee s requirements b that the Software will operate in the hardware or software combinations that the Licensee may select c that the operation of the Software will be uninterrupted or error free or d that all defects in the operation of the Software will be corrected Nortel Networks is not obligated to remedy any Software defect that cannot be reproduced with the latest Software release These warranties do not apply to the Software if it has been i altered except by Nortel Networks or in accordance with its instructions ii used in conjunction with another vendor s product resulting in the defect or iii damaged by improper environment abuse misuse accident or negligence THE FOREGOING WARRANTIES AND LIMITATIONS ARE EXCLUSIVE REMEDIES AND ARE IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING WITHOUT LIMITATION ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE Licensee is responsible 308628 15 0 Rev 00 iii for the security of its own data and information and for maintaining adequate procedures apart from the Software to reconstruct lost or altered files data or
163. icy Filters gt BGP 4 gt Announce Policies An empty list A list of autonomous system numbers Specifies one or more autonomous system numbers This policy applies to EGP advertisements received from EGP peers in an AS on this list and applies only to EGP sourced routes when EGP is included as a route source Specify one or more AS numbers Use the default empty list to indicate that this policy applies to EGP advertisements from peers in any AS EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 17 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 17 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 17 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Received EGP Gateway Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of IP addresses Specifies the IP address of one or more EGP gateways This policy applies to EGP advertisements that use a gateway on this list as the next hop and applies only to EGP sourced routes when EGP is included as a route source Specify one or more IP addresses Use the default empty list to indicate that this policy a
164. ies 0ceeeee 5 17 Table 5 6 BCC Modification Parameters for BGP Announce Policies 5 22 Table 5 7 Characters in AS Path Pattern Matching ccccscessseeeeeeeeeseeeetenes 5 27 Table 7 1 IBGP EOMP AS carian aa 7 4 Table 7 2 EBOP EOMP Mo DOGE cicirine inniinn non E 7 8 Table 8 1 Router Mode Determinator ssasiesecessonvscicsisnonseasesiorscersaoaaavees sasenssiahaossaranie s 8 3 Table B 1 Cisco to Nortel Networks BGP Translation n B 2 Table B 2 Cisco and Nortel Networks BGP Operational Commands 0006 B 8 Table B 3 Route Selection Process Comparison ccccccececeeseneceeeeeeeeeaeeeneeeees B 11 Table B 4 Regular Expression Symbole sensaro eii iie B 12 Table B 5 Nortel Networks AS Path Pattern Matching Symbols ceeee B 13 308628 15 0 Rev 00 xiii Preface Routers at the borders or edges of autonomous systems are called gateways These gateways use exterior gateway protocols to exchange reachability information with each other and route packets between routing domains This guide describes how to configure and use the IP Border Gateway Protocol BGP and the Exterior Gateway Protocol EGP You can use the Bay Command Console BCC or Site Manager to configure BGP and EGP on a router In this guide you will find instructions for using both the BCC and Site Manager Before You Begin Before using this guide you must complete the following procedures F
165. ies only to OSPF sourced routes when OSPF is included as a route source To match any route type enter Any To match any non ASE route enter Internal To match any ASE route enter External To match any external type 1 route enter Type 1 To match any external type 2 route enter Type 2 EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 14 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 14 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 14 A 60 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters Received OSPF Tag Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of tag values Specifies tag values that could be present in an OSPF ASE advertisement This policy applies to OSPF ASE advertisements that contain tag values in this list and applies only to OSPF sourced ASE routes when OSPF is included as a route source Specify one or more tag values Use the default empty list to indicate that this policy applies to OSPF ASEs with any tag value EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 15 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 15 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 15 308628 15
166. igh order bits EGP cannot advertise or interpret subnets or supernets 8 2 308628 15 0 Rev 00 Customizing EGP Services An EGP router does the following e Acquires EGP neighbors e Determines neighbor reachability e Exchanges network reachability information with its neighbors Each of these capabilities has an associated phase in EGP the neighbor acquisition phase the neighbor reachability phase and the network reachability phase respectively In the acquisition phase EGP is responsible for forming neighbor relationships between routers that are peers Routers that are peers each have an interface to a common network One router attempts to acquire a peer router If the peer agrees to be acquired the two routers form a neighbor relationship They then negotiate the mode of operation and the polling modes After two routers agree to form a neighbor relationship they must then negotiate modes According to EGP the routers modes are determined as shown in Table 8 1 Table 8 1 Router Mode Determinator Router A Router B Resulting Modes Active Passive Router A is active Router B is passive Passive Passive Not allowed at least one router must be active Active Active The router with the lower autonomous system number becomes active the other becomes the passive router Both Active Router A is passive Router B is active Both Passive Router A is active Router B is passive Both Both The router
167. iguring BGP Message Logging By default the router logs only a few event messages generated by BGP To troubleshoot a problem you can configure the router to log BGP event messages for the entire router or for a specific peer to peer session by specifying e Local and remote addresses of a peer to peer session or sessions e Message severity level fault warning information trace debug or all levels e BGP message type open keepalive update or notification When you are not troubleshooting a problem configure BGP message logging to limit the number of debug messages that BGP generates and logs If you allow BGP to log all debug messages the debug messages will overrun and overwrite the log file Note For more information about event messages see the BayRS event message database at http www25 nortelnetworks com library tpubs events You also can access the event message database from the BayRS documentation CD Using the BCC To configure BGP event message logging go to the debug control prompt for example box ip bgp debug control or box ip bgp peer 2 2 2 2 2 2 2 4 debug conirol and enter log message type debug info warning fault trace all levels log packet type disabled open update notification keepalive To disable event message logging set the log packet type parameter to disabled the default value 308628 15 0 Rev 00 3 29 Configuring IP Exterior Gateway Protocols BGP
168. ilters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies Direct Static RIP OSPF EGP and BGP Direct Static RIP OSPF EGP BGP Specifies one or more route source identifiers If you select a route source ID a route from that source that meets the other criteria of this policy matches the policy To specify any source use the default EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 8 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 8 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 8 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Advertise Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of network identifiers Specifies network IDs to include in place of the network IDs listed in the route to be advertised Specify a non null value only if the announce Action parameter is The values you enter in the advertise list determine the action taken If you supply a list of network IDs these IDs are advertised instead of the actual IDs in the route
169. ilters gt distribute list 5 in accept IncomingRoutes BGP 4 gt Accept Policies gt Add access list 5 permit action accept match Name IncomingRoutes 128 1 0 0 0 0 255 255 network 128 1 0 0 Action ACCEPT 255 255 0 0 range back Network List gt List peer 1 1 1 1 Network Number 128 1 0 0 Network Mask 255 255 0 0 Match Criteria range Peer Address 1 1 1 1 4 neighbor 1 1 1 1 ip bgp Protocols gt IP gt Policy Filters gt distribute list 10 out announce OutgoingRoutes BGP 4 gt Announce Policies gt Add access list 10 permit action announce Name OutgoingRoutes 195 89 32 0 0 0 31 255 modify Action ANNOUNCE advertise 195 89 32 0 Advertise List gt List 255 255 224 0 Network Number 195 89 32 0 back back Network Mask 255 255 224 0 Match match Criteria range outbound peer 1 1 1 1 Outbound Peers 1 1 1 1 5 neighbor 1 1 1 1 route map ip bgp Protocols gt IP gt Policy Filters gt IncomingMap in accept IncomingMap BGP 4 gt Accept Policies gt Add foute map action accept match Name IncomingMap IncomingMap permit 10 as path pattern Action ACCEPT match as path 5 333 444 345 back AS Pattern 333 444 345 set local preference 125 peer 1 1 1 1 back back Local Preference 125 lp as path access list 5 modify local preference 125 Peer Address 1 1 1 1 permit 333_ 444 345 continued B 2 308628 15 0 Rev 00 Converting Cisco to Nortel Networks Equivalents Table B 1 Cisco to Nortel Networks BGP Translation continued Item Cisco Configuration
170. in edit parameters the window 8 Set the KeepAlive Timer parameter Click on Help or see the parameter description on page A 15 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window Setting the External Advertisement Timer After a connection is established the BGP speaker uses one or more update messages to send the entire IP routing table compliant with local BGP announce policies BGP however does not require the entire routing table to be sent again Therefore the BGP speaker must keep a current version of the routing information received from all its peers for as long as the connection to each peer is valid This information is updated by means of update messages whenever changes occur By default BGP examines the routing table for changes every 30 seconds If a change has occurred BGP issues an update message on the connection You can use the BCC or Site Manager to specify a value for the external advertisement timer Using the BCC To specify a value for the external advertisement timer go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter advertise time lt seconds gt seconds is an integer from 1 through 2 147 483 647 specifying the minimum interval at which BGP examines the routing table for changes before issuing an update message on this peer session 308628 15 0 Rev 00 4 9 Configuring IP Exterior Gateway Proto
171. is 6 Set the following parameters Peer Address Peer AS Local Address Peer Mode Click on Help or see the parameter descriptions beginning on page A 11 System responds 7 Click on OK Deleting BGP with Site Manager Site Manager enables default BGP service and returns you to the Configuration Manager window You can delete BGP from all router circuits on which it is currently enabled To delete BGP using Site Manager complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Delete BGP Site Manager asks you to confirm the deletion of BGP 5 Click on OK Site Manager removes BGP from all circuits on the router and returns you to the Configuration Manager window 308628 15 0 Rev 00 Starting BGP and EGP Services Deleting BGP 3 and BGP 4 with Site Manager You can delete BGP 3 and BGP 4 from all router circuits on which they are currently enabled To delete BGP 3 using Site Manager complete the following steps Site Manager Procedure You do this System responds 1 Inthe Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choos
172. is list this policy applies to BGP advertisements being sent to BGP peers in that AS outbound peer List of IP addresses Specifies the IP address of one or more BGP peers If a BGP peer is included in this list this policy applies to BGP advertisements being sent to that BGP peer continued 308628 15 0 Rev 00 5 19 Configuring IP Exterior Gateway Protocols BGP and EGP Table 5 5 BCC Match Parameters for BGP Announce Policies continued Parameter Values Function rip gateway List of IP addresses Specifies the addresses of one or more routers that could send RIP updates to this router This policy applies to RIP advertisements from routers on this list and applies only to RIP sourced routes when RIP is included as a route source rip interface List of IP addresses Specifies the IP addresses of one or more interfaces on this router This policy matches RIP updates received on interfaces that appear in this list An empty list indicates that this policy applies to RIP updates received on any interface This item is a BCC object with parameters of its own To specify multiple items create multiple objects Examples The following command sequence configures the router to advertise updates authored by BGP peer 1 1 1 1 announce pol_3 bgp action announce announce pol_3 bgp match match bgp announce pol_3 inbound peer 1 1 1 1 inbound peer 1 1 1 1 bgp announce pol_3
173. ite Manager Using the BCC To establish a peer to peer session with another route reflector in the same cluster go to the BGP prompt for example box ip bgp and enter peer local lt ocal_reflector_address gt remote lt remote_reflector_address gt as lt as_number gt local_reflector_address is the IP address on the local route reflector remote_reflector_address is the IP address on the remote route reflector as_numberis the AS where the remote reflector resides Because the local and remote reflectors reside in the same AS BGP recognizes that this is an IBGP session At the session specific prompt enter the following command to specify that the remote route reflector is an internal peer that is located in the same cluster peer mode reflector internal For example the following command sequence defines a peer to peer session between two route reflectors represented by addresses 2 2 2 2 and 2 2 2 3 located in the same cluster in AS 2 bgp peer local 2 2 2 2 remote 2 2 2 3 as 2 peer 2 2 2 2 2 2 2 3 peer mode reflector internal peer 2 2 2 2 2 2 2 3 308628 15 0 Rev 00 6 5 Configuring IP Exterior Gateway Protocols BGP and EGP Using Site Manager To establish a peer to peer session with another route reflector in the same cluster complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose
174. jections For example the following command causes BGP to inject external BGP routes into the routing table with a minimum interval of 10 seconds bgp inject time 10 bgp 3 10 308628 15 0 Rev 00 Configuring Global BGP Parameters Using Site Manager To change the minimum number of seconds between route injections complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the BGP Interval Timer parameter Click on Help or see the parameter description on page A 6 6 Click on OK You return to the Configuration Manager window Allowing Redundant Connections By default BGP performs redundancy checking on peer to peer TCP sessions BGP can maintain only one TCP session with a remote BGP peer If the remote peer attempts to establish another session on another physical connection BGP rejects the session BGP uses a collision detection method based on the router ID to check for redundant sessions You can disable redundancy checking to allow TCP sessions with the same remote peer on multiple physical connections The advantage of a peer to peer configuration with multiple sessions on multiple physical connections is redundancy if one connection
175. licy determines the external routes that BGP includes in the IP routing table e An announce policy determines the routes in the routing table that BGP advertises to other routers Note By default an external BGP 3 or BGP 4 speaker will neither advertise any routes to a peer nor inject any routes into its IGP Route policies must be configured to enable any route advertisement To ensure that every BGP border router within an AS comes to the same decision in constructing path attributes for an external path routing policies must be coordinated among all BGP speakers within an AS Nortel Networks recommends that the accept and announce policies on all IBGP connections accept and advertise all routes On external BGP connections you must make consistent routing policy decisions Note In addition to announce and accept policies Nortel Networks supports import and export filters for BGP 3 Import and export filters provide a subset of the parameters provided by the policies For information about configuring import and export filters see Configuring IP ARP RARP RIP and OSPF Services 308628 15 0 Rev 00 5 1 Configuring IP Exterior Gateway Protocols BGP and EGP When a BGP speaker receives a route in an update message it applies any local routing policies to determine whether the router will use the route and whether it will advertise the route to other routers Then if the route can be used it is compared against
176. lies only to BGP sourced routes when BGP is included as a route source Specify one or more IP addresses Use the default empty list to indicate that this policy applies to BGP advertisements with any Next Hop attribute EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 21 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 21 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 21 308628 15 0 Rev 00 A 67 Configuring IP Exterior Gateway Protocols BGP and EGP EGP Specific Announce Policy Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID External Route Source Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Any Direct Static RIP OSPF with Type 2 metric EGP BGP Any Specifies one or more external route source identifiers If you specify an external route source a route from that source that meets the other criteria of this policy matches the policy This parameter applies only to OSPF routes that use the new ASE type 2 metric The protocol from which OSPF received the route is encoded in the ASE metric along with the route s metric To specify any external route source use the default 1 3 6 1 4 1 18 3 5 3 2 6 6 1 9 EGP Peer List Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies An empty list A list of IP addresses Sp
177. main suppressed memory limit 45 Specifies the maximum number of minutes 1 through 60 that the status of a route can remain unchanged reachable or unreachable before BGP resets the penalty value and flap count to 0 and unsuppresses the route To apply the template to an inbound BGP routing update 1 Go to the BGP prompt for example box ip bgp 2 Create and name a BGP accept policy For instructions on creating a BGP accept policy see Configuring a BGP Accept Policy on page 5 2 An accept policy specific prompt appears 308628 15 0 Rev 00 3 33 Configuring IP Exterior Gateway Protocols BGP and EGP 3 Modify the accept policy by entering the following commands action accept route damping enabled route damping template default lt name gt name is the name of the template that you want to apply to the unstable route 4 Match the accept policy to the unstable route For instructions see Specifying Match Criteria for a BGP Accept Policy on page 5 6 For example the following command sequence creates a BGP accept policy named fred that causes BGP to apply the route flap damping template steady to updates for network 3 4 0 0 bgp accept fred accept fred bgp action accept accept fred bgp route damping enabled accept fred bgp route damping template steady accept fred bgp match match bgp accept fred network 3 4 0 0 16 exact network 3 4 0 0 255 255 0 0 exact bgp acce
178. meter Click on Help or see the parameter description on page A 26 continued 308628 15 0 Rev 00 8 9 Configuring IP Exterior Gateway Protocols BGP and EGP Site Manager Procedure continued You do this System responds 9 Click on Apply and then click on Done You return to the IP Interface List for EGP window 10 Click on Done You return to the Configuration Manager window Enabling and Disabling the Neighbor Relationship When you establish a neighbor to neighbor relationship on an interface the relationship is automatically enabled To temporarily disable this neighbor relationship rather than delete it complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose EGP The EGP menu opens 4 Choose Neighbors The IP Interface List for EGP window opens 5 Click on the IP interface that you want to edit The parameter values for that interface appear in the window 6 Click on EGP Neighbor The EGP Neighbors List window opens 7 Click on the address of the EGP neighbor that you want to edit The parameter values for that neighbor appear in the window 8 Set the Enable parameter Click on Help or see the parameter description on page A 27 9 Click
179. meter Select Replace to replace the existing communities with the communities you specified 1 3 6 1 4 1 18 3 5 3 2 6 10 1 34 BGP Communities to match Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of BGP communities Specifies one or more BGP communities This policy applies to all BGP advertisements that match the list Supply an octet string using the following format each community ID is 4 bytes long 0 in the two most significant bits causes the router to perform the match on the lower 16 bits the default empty list means match any list 1 3 6 1 4 1 18 3 5 3 2 6 10 1 35 A 80 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters As Prepend Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of autonomous systems Specifies one or more AS numbers to be added as a SEQUENCE to AS Path Supply an octet string containing AS numbers to be added as a SEQUENCE to AS Path 1 3 6 1 4 1 18 3 5 3 2 6 9 1 36 308628 15 0 Rev 00 Appendix B Converting Cisco to Nortel Networks Equivalents This appendix shows you how to change Cisco commands and functions to Nortel Networks equivalents Topic Page Configuration Command Equivalents B 1 Interpreting
180. mit and receive current routing information over a reliable transport layer connection making periodic updates unnecessary BGP is designed for inter AS exchanges but can be used between multiple routing domains for example RIP to OSPF BGP peers exchange complete routing information only after the peer connection is established Thereafter BGP peers exchange routing updates An update includes a network number a list of autonomous systems that the routing information passed through the AS path and other path attributes that describe the route to a set of destination networks When multiple paths are available BGP compares the path attributes to choose the preferred path BGP exchanges information between ASs as well as between routers in the same AS To differentiate between these uses the latter is called interior BGP IBGP Exterior Gateway Protocol EGP You use the Exterior Gateway Protocol to exchange network reachability information between routers in different autonomous systems An interior gateway protocol IGP such as RIP or OSPF is used within an AS to facilitate the communication of routing information within an autonomous system The routers that serve as the end points of a connection between two autonomous systems also run an exterior gateway protocol such as EGP 2 Routers establish EGP neighbor relationships to periodically exchange reliable network reachability information EGP neighbors exchange complete reach
181. mplate Enter a string that uniquely identifies the route flap dampening template 1 3 6 1 4 1 18 3 5 3 2 5 1 8 1 3 Cutoff Threshold Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies gt Route Flap 2000 1 to 20000 Specifies the maximum threshold for the route penalty value If the penalty value rises above the value for this parameter BGP suppresses the route The router increments the penalty value by 1000 for each withdrawal and increments it by 500 for each reachable announcement Enter a number for the cutoff penalty value 1 3 6 1 4 1 18 3 5 3 2 5 1 8 1 4 308628 15 0 Rev 00 A 47 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Reuse Threshold Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies gt Route Flap 750 1 to 20000 Specifies the minimum threshold for the route penalty value If the penalty value falls below the value you enter for this parameter BGP no longer suppresses the route The penalty value decreases over time based on the values you set for the Reachable Decay and Unreachable Decay parameters Enter a number for the reuse penalty value 1 3 6 1 4 1 18 3 5 3 2 5 1 8 1 5 Reachable Decay Configuration Manager gt Protocols g
182. mple the following command configures BGP to advertise routes to both RIP and OSPF bgp igp interaction ospf rip bgp Using Site Manager To configure the router to advertise BGP learned information to OSPF RIP or both complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens continued 308628 15 0 Rev 00 3 9 Configuring IP Exterior Gateway Protocols BGP and EGP Site Manager Procedure continued You do this System responds 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the BGP IGP Interaction Conirol parameter Click on Help or see the parameter description on page A 10 6 Click on OK You return to the Configuration Manager window Setting the Update Interval Timer BGP periodically injects external BGP routes into the routing table The default minimum interval between route injections is 5 seconds You can use the BCC or Site Manager to change the minimum number of seconds between route injections Using the BCC To change the minimum number of seconds between route injections go to the BGP prompt for example box ip bgp and enter inject time lt seconds gt seconds is the minimum interval from through 2 147 483 647 between route in
183. nd OSPF includes the ability to advertise supernets to support classless interdomain routing CIDR BGP 4 allows interdomain supernet advertisements OSPF can carry supernet advertisements within a routing domain 308628 15 0 Rev 00 Exterior Gateway Protocols BGP and EGP BGP 4 Confederations The BGP confederation feature can reduce the size and complexity of an IBGP mesh by breaking large autonomous systems into a confederation of smaller subautonomous systems This division reduces the size of IBGP meshes and the complexity of the associated configuration management Other autonomous systems view the confederation as a single AS with the confederation ID as its AS number BGP confederations are available only with BGP 4 The BGP 4 confederation feature complies with RFC 1965 and provides the following functions e Lets you configure a confederation ID on the router e Implements new AS_PATH segment types e Lets you configure new AS_PATH variables AS_CONFED_SET and AS_CONFED_SEQUENCE for specifying confederation parameters e Implements correct AS_PATH setting and manipulation to neighboring autonomous systems that are within and outside the confederation See Configuring BGP 4 Confederations on page 3 21 for a detailed description of this feature and for configuration information BGP 4 TCP MD5 Message Authentication BGP 4 lets you configure the authentication of BGP messages by TCP MD5 signatures in compliance wi
184. nections BGP enabling 3 13 Multi hop EBGP Connection parameter 3 14 A 7 N negotiating the BGP version 4 6 next hop BGP configuring 4 17 Node Protection Key parameter 4 27 A 19 Nortel Networks AS path pattern matching symbols B 13 Nortel Networks BGP best route calculation and Cisco equivalent B 11 Nortel Networks commands and Cisco equivalents B 1 Index 3 O OSPF BQP interaction described 1 10 enabling 3 9 P path weight AS 3 26 pattern matching AS path 5 27 Peer Address parameter BGP peer 2 4 A 11 in multiple RR cluster configuration 6 8 in peer to peer session definition 4 3 in route reflector cluster configuration 6 6 in RR client configuration 6 11 in single route reflector configuration 6 4 Peer AS parameter BGP peer 2 4 A 12 in multiple RR cluster configuration 6 8 in peer to peer session definition 4 3 in route reflector cluster configuration 6 6 in RR client configuration 6 11 in single route reflector configuration 6 4 Peer EBGP ECMP parameter 7 9 A 18 peer local command 4 2 Peer Local Remote parameter 3 30 A 24 Peer Max Update Size parameter 4 15 A 16 Peer Route Echo Switch parameter 4 18 4 19 A 17 peers BGP configuring 4 1 penalty value used in route flap damping 3 31 policies 5 1 policy parameters Action accept A 32 Action announce A 53 Advertise announce A 56 Aggregator AS List accept A 42 Aggregator Router List acce
185. nfiguring IP Exterior Gateway Protocols BGP and EGP Choosing the Poll Mode The type of neighbor reachability algorithm executed by the local EGP neighbor is called the poll mode There are two poll modes active and passive In the active mode a router sends Hello and poll messages to request reachability status from its neighbor In the passive mode a router responds to Hello and poll messages with I H U and update messages By default EGP is configured to execute both the active and passive poll modes To execute the active or passive mode only complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens edit 2 Choose IP The IP menu opens 3 Choose EGP The EGP menu opens 4 Choose Neighbors The IP Interface List for EGP window opens 5 Click on the IP interface that you want to The parameter values for that interface appear in the window 6 Click on EGP Neighbor 7 Click on the address of the EGP neighbor that you want to edit The EGP Neighbors List window opens The parameter values for that neighbor appear in the window Set the Poll Mode parameter Click on Help or see the parameter description on page A 27 Click on Apply and then click on Done You return to the IP Interface List for EGP window 10 Click on Done You return to the C
186. ng a list of the ASs that must be traversed to reach the given destinations Origin Mandatory attribute containing one of the following values IGP the path is valid all the way to the IGP of the originating AS EGP the path was advertised using EGP by the last AS in the AS path Incomplete the path is valid only to the last AS in the AS path Next hop Inter AS Mandatory attribute that specifies the IP address of the router to use as a next hop for the advertised destinations Optional attribute used to choose between paths to the destinations listed Unreachable Discretionary attribute used to indicate destinations that have become unreachable A BGP 4 update message has a variable length sequence of path attributes Each attribute includes an attribute value and an attribute description Table 1 2 lists the mandatory BGP 4 path attributes Table 1 2 BGP 4 Mandatory Path Attributes Attribute Description AS path Contains a list of the ASs that must be traversed to reach the given destinations Origin Contains one of the following values IGP the path is valid all the way to the IGP of the originating AS EGP the path was advertised using an EGP by the last AS in the AS path Incomplete the path is valid only to the last AS in the AS path Next hop Specifies the IP address of the router to use as a next hop for the advertised destinations
187. ning on page A 30 Click on OK You return to the BGP4 Accept Policy Filters window 308628 15 0 Rev 00 5 5 Configuring IP Exterior Gateway Protocols BGP and EGP Specifying Match Criteria for a BGP Accept Policy You can use the BCC or Site Manager to specify match criteria for BGP accept policies Using the BCC To specify match criteria for a BGP accept policy go to the BGP policy prompt for example box ip bgp accept policy_1 and enter match The match prompt appears for the policy For example accept pol_1 bgp match match bgp accept pol_l To specify match criteria enter lt match_parameter gt lt value gt Table 5 2 lists the parameters and values that you can enter 5 6 308628 15 0 Rev 00 Table 5 2 Configuring BGP Accept and Announce Policies BCC Match Parameters for BGP Accept Policies Parameter Values Function as path pattern null or any regular expression Allows AS path pattern matching Enter a valid regular expression to indicate an AS and its position in a path see Table 5 7 The policy applies to all routes whose AS path includes the AS in that position For example the expression 200 means that the policy applies to all routes whose as_path attribute contains AS 200 as the last AS in the path origin any default igp egp incomplete Specifies values of the BGP origin path attribute This policy applies to BGP adver
188. o create a route flap damping template go to the BGP prompt for example box ip bgp and enter damping template name lt name gt name is a unique name identifying the template from 1 through 20 characters A template specific prompt appears For example the following command creates a route flap damping template named steady bgp damping template name steady damping template steady To change the default values of the parameters for a template that you created go to the template specific prompt for example box ip bgp damping template steady and enter lt parameter gt lt value gt Table 3 6 lists the parameters and values that you can enter 3 32 308628 15 0 Rev 00 Configuring Global BGP Parameters Table 3 6 Route Flap Damping Template Parameters Parameter Default Value Meaning cutoff threshold 2000 Specifies a maximum threshold 1 through 20000 for the route penalty value reuse threshold 750 Specifies a minimum threshold 1 through 20000 for the route penalty value reachable decay 5 Specifies the number of minutes 1 through 45 that the route can remain reachable before BGP decrements the penalty value by half unreachable decay 15 Specifies the number of minutes 1 through 45 that the route can remain unreachable before BGP decrements the penalty value by half max hold down 45 Specifies the maximum number of minutes 1 through 60 that a route can re
189. ocedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on Add The BGP Peer window opens 8 Set the following parameters e Peer Address Peer AS e Local Address Click on Help or see the parameter descriptions beginning on page A 11 9 Set the Peer Mode parameter to Reflector External continued 6 8 308628 15 0 Rev 00 Configuring a Route Reflector Site Manager Procedure continued You do this 10 Click on OK System responds You return to the BGP Peer List window 11 Click on Apply and then click on Done You return to the IP Interface List for BGP window To associate a route reflector with a cluster complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the Cluster Identifier parameter Click on Help or see the
190. oint network Router A Router B Numbered IP interface configured for a BGP peer to peer connection Unnumbered IP interface 1P0049B Figure 4 2 BGP over an Unnumbered Point to Point Link 308628 15 0 Rev 00 4 21 Configuring IP Exterior Gateway Protocols BGP and EGP To establish a peer to peer session between router A and router B 1 Select a numbered interface on each router for the peer to peer session Note the network and subnet that each interface is on In Figure 4 2 router A has a numbered interface to network 1 Router B has a numbered interface to network 3 The network administrator selects these two interfaces to support the peer to peer session 2 If the two routers are in different ASs enable multihop EBGP connections See Enabling Multihop Connections on page 3 13 3 If no interior gateway protocol RIP or OSPF is running over the unnumbered link configure a static route on each router to the other router s network and subnet Because the routers do not share a numbered subnet each BGP peer needs to know a route to the network and subnet of the interface that the other BGP peer uses If an IGP RIP or OSPF is running over the unnumbered link RIP or OSPF learns the route and stores it in the routing table Otherwise you need to configure a static route on each router to the other BGP peer s network subnet The route should point to the unnumbered link 4 Configure the BGP conne
191. on OK You return to the BGP AS Weight Parameters window 8 Click on Done You return to the Configuration Manager window 3 38 308628 15 0 Rev 00 Chapter 4 Configuring BGP Peers A BGP speaker forms a neighbor relationship by establishing a TCP connection to another BGP speaker or peer based on local configuration information You can configure a BGP peer to peer session by setting the BGP parameters described in the following sections Topic Page Defining a Peer to Peer Session 4 2 Initiating a Peer to Peer Session 4 4 Negotiating the BGP Version 4 6 Keeping the Connection Alive 4 8 Setting the External Advertisement Timer 4 9 Specifying a Holddown Time 4 11 Setting a Minimum AS Origination Interval 4 12 Overriding the Local AS Number 4 14 Specifying a Maximum Update Size 4 14 Specifying a Time to Live Value 4 16 Specifying the Next Hop Router 4 17 Setting the Route Echo Switch 4 18 Disabling and Reenabling Loop Detection 4 20 Configuring Peers over an Unnumbered Point to Point Link 4 21 Configuring and Enabling MD5 Authentication 4 22 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Defining a Peer to Peer Session To define a peer to peer session specify the following e Local IP interface address e Remote IP interface address e AS number of the autonomous system in which the remote BGP peer is located In confi
192. onfiguration Manager window 8 12 308628 15 0 Rev 00 Setting Neighbor Timers Customizing EGP Services EGP uses two configurable timers the Hello timer and the poll timer The Hello timer determines the number of seconds between the local EGP neighbor s EGP Hello message retransmissions This variable represents the RFC 904 T1 timer By default EGP sends a Hello message every 60 seconds You can supply a value from 30 through 120 seconds The poll timer determines the interval between the local EGP neighbor s EGP poll message retransmissions This variable represents the RFC 904 T2 timer By default EGP retransmits a poll message every 180 seconds You can specify a value from 120 through 480 seconds To set the local EGP neighbor s Hello or poll timer complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose EGP The EGP menu opens 4 Choose Neighbors The IP Interface List for EGP window opens Click on the IP interface that you want to edit The parameter values for that interface appear in the window 6 Click on EGP Neighbor The EGP Neighbors List window opens 7 Click on the address of the EGP neighbor that you want to edit The parameter values for that neighbor appear in the window
193. or a new router e Install the router see the installation guide that came with your router e Connect the router to the network and create a pilot configuration file see Quick Starting Routers Configuring Remote Access for AN and Passport ARN Routers or Connecting ASN Routers to a Network Make sure that you are running the latest version of Nortel Networks BayRS and Site Manager software For information about upgrading BayRS and Site Manager see the upgrading guide for your version of BayRS 308628 15 0 Rev 00 XV Configuring IP Exterior Gateway Protocols BGP and EGP Text Conventions This guide uses the following text conventions angle brackets lt gt bold text braces brackets ellipsis points Indicate that you choose the text to enter based on the description inside the brackets Do not type the brackets when entering the command Example If the command syntax is ping lt p_address gt you enter ping 192 32 10 12 Indicates command names and options and text that you need to enter Example Enter show ip alerts routes Example Use the dinfo command Indicate required elements in syntax descriptions where there is more than one option You must choose only one of the options Do not type the braces when entering the command Example If the command syntax is show ip alerts routes you must enter either show ip alerts or show ip routes but not both
194. ose the route with the lower multiexit discriminator MED attribute if both routes include this optional attribute Choose the route with the lower interior cost to the next hop Choose external BGP over IBGP Choose the route with the lower BGP identifier Choose the route with the lower BGP connection remote address Choose the route with the lower BGP connection local address Calculated Preference Tiebreaker Rules local pref calculation disabled Al 2 3 4 8 10 If the next hop is inaccessible do not consider it Consider larger BGP administrative weights first If the routes have the same weight consider the route with the highest local preference If the routes have the same local preference prefer the route that the local router originated If no route was locally originated prefer the shorter AS path If the routes have the same AS path length prefer the lowest origin code IGP is preferred over EGP which is preferred over incomplete If the origin codes are the same and all paths come from the AS prefer the path with the lowest multiexit discriminator MED metric Treat a missing MED metric as 0 If the MED metrics are the same prefer external paths over internal paths If IGP synchronization is disabled and only internal paths remain prefer the path through the closest neighbor Prefer the route with the lowest IP address value for the BGP router ID Using the BCC To config
195. ote as 4002 peer 3 4 5 1 3 4 5 6 as 510 neighbor 3 4 5 6 remote as 510 19 router bgp 1000 ip bgp Protocols gt IP gt BGP gt Peers neighbor 132 245 10 2 local as 1000 Local AS 1000 password bla4u00 2nkq peer 132 245 10 1 132 245 10 2 as 1000 tcp authentication md5 tcp md5 key bla4u00 2nkq Peer Address 132 245 10 2 Peer AS 1000 Local Address 132 245 10 1 Tcp Authentication MD5 TcpMd5Key bla4u00 2nkq 308628 15 0 Rev 00 B 5 Configuring IP Exterior Gateway Protocols BGP and EGP Interpreting the Configuration Command Equivalents Table The numbers in the following list correspond to the item numbers in Table B 1 Each item describes the function of the commands in the corresponding row 1 Enable the Border Gateway Protocol BGP routing process and identify the local router autonomous system AS 333 Activate a BGP session with peer router IP address 1 1 1 2 that belongs to AS 444 If the local and remote AS numbers are the same the BGP session is internal otherwise it is an external session Note that Nortel Networks also requires definition of the local router IP address 1 1 1 1 2 Advertise network 1 1 1 0 mask 255 255 255 0 and originate it from the local AS Note that network 1 1 1 0 must be present in the IP routing table for Cisco s BGP network command to advertise the route 3 Accept incoming advertisement of network 128 1 0 0 mask 255 255 0 0 from peer IP address 1 1 1 1 as specified by
196. our octet community number in the form AS_number value Entering 0 in the two most significant bits causes the router to match on the lower 16 bits egp as List of AS numbers Specifies one or more autonomous system numbers This policy applies to EGP advertisements received from EGP peers in an AS on this list and applies only to EGP sourced routes when EGP is included as a route source egp gateway List of IP addresses Specifies the IP address of one or more EGP gateways This policy applies to EGP advertisements that use a gateway on this list as the next hop and applies only to EGP sourced routes when EGP is included as a route source egp peer List of IP addresses Specifies the IP address of one or more EGP peers This policy applies to EGP advertisements authored by a router on this list and applies only to EGP sourced routes when EGP is included as a route source inbound as List of AS numbers Specifies a list of AS numbers If an AS number is included in this list this policy applies to BGP advertisements received from BGP peers in that AS inbound peer List of IP addresses Specifies the IP address of one or more BGP peers This policy applies to BGP advertisements authored by a router on this list and applies only to BGP sourced routes when BGP is included as a route source continued 5 18 308628 15 0 Rev 00 Table 5 5 Parameter Configuring B
197. ources bgp redistribute protocols all bgp Using Site Manager To specify the types of routes that BGP advertises in IBGP sessions complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens Set the BGP From Protocols parameter Click on Help or see the parameter description on page A 5 Click on OK You return to the Configuration Manager window 3 8 308628 15 0 Rev 00 Configuring Global BGP Parameters Enabling BGP Interaction with OSPF and RIP By default BGP does not exchange routes with OSPF or RIP However you can configure the router to allow BGP to advertise BGP learned routes to OSPF RIP or both OSPF and RIP You can use the BCC or Site Manager to configure the router to advertise BGP learned routes Using the BCC To configure the router to advertise BGP learned information to OSPF RIP or both go to the BGP prompt for example box ip bgp and enter igp interaction lt protocols gt protocols is one of the following values e none default BGP advertises no routes to OSPF or RIP e ospf BGP advertises BGP learned routes to OSPF e rip BGP advertises BGP learned routes to RIP For exa
198. p Detection Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers Enabled Enabled Disabled Specifies whether BGP terminates a peer to peer session if it discovers a loop in the AS path Set this parameter as required 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 41 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Next Hop Self Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers Disable Enable Disable Enables or disables the use of third party advertisements Specify Enable to send the local peer s address as the next hop in all advertisements Accept the default Disable to allow third party advertisements 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 40 Peer EBGP ECMP Method Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers Disabled Disabled Route Balance Traffic Balance Configures BGP to use ECMP routes in the routing table for route balancing or traffic load balancing To configure BGP to use ECMP routes for route balancing set this parameter to Route Balance To configure BGP to use ECMP routes for traffic load balancing set this parameter to Traffic Balance 1 3 6 1 4
199. page A 51 8 Click on OK You return to the BGP4 Announce Policy Filters window 9 Click on Done You return to the Configuration Manager window 308628 15 0 Rev 00 5 15 Configuring IP Exterior Gateway Protocols BGP and EGP Specifying Match Criteria fora BGP Announce Policy You can use the BCC or Site Manager to specify match criteria for a BGP announce policy Using the BCC To specify match criteria for a BGP announce policy go to the policy prompt for example box ip bgp announce pol_1 and enter match For example the following command invokes the match prompt for BGP announce policy pol_1 announce pol_1 bgp match match bgp announce pol_1l To specify match criteria enter lt match_criterion gt lt value gt Table 5 5 lists the criteria and values that you can enter 5 16 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies Table 5 5 BCC Match Parameters for BGP Announce Policies Parameter Values Function as path pattern Empty string Allows AS path pattern matching Enter a valid default or regular expression to indicate an AS and its any regular position in a path see Table 5 7 The policy expression applies to all routes whose AS path includes the AS in that position For example the expression 200 means that the policy applies to all routes whose as_path attribute contains AS 200 as the last AS in the path external source
200. parameter description on page A 8 6 Click on OK You return to the Configuration Manager window 308628 15 0 Rev 00 6 9 Configuring IP Exterior Gateway Protocols BGP and EGP Configuring an RR Client An RR client is a BGP IBGP speaker with a peer to peer session with a route reflector and one or more peer to peer sessions with external BGP speakers You can use the BCC or Site Manager to establish a peer to peer session with one or more route reflectors in the same cluster Using the BCC To establish a peer to peer session between an RR client and a route reflector in the same cluster go to the BGP prompt for example box ip bgp and enter peer local lt client_address gt remote lt reflector_address gt as lt as_number gt client_address is the IP address on the local client reflector_address is the IP address on the remote reflector as_numberis the AS where the client and the server reside At the session specific prompt enter peer mode none For example the following command sequence defines a peer to peer session between an RR client and a route reflector represented by addresses 2 2 2 2 and 2 2 2 3 bgp peer local 2 2 2 2 remote 2 2 2 3 as 2 peer 2 2 2 2 2 2 2 3 peer mode none peer 2 2 2 2 2 2 2 3 6 10 308628 15 0 Rev 00 Configuring a Route Reflector Using Site Manager To establish a peer to peer session between an RR client and a route reflector complete the following step
201. plicable 6 Use of software in the European Community This provision applies to all Software acquired for use within the European Community If Licensee uses the Software within a country in the European Community the Software Directive enacted by the Council of European Communities Directive dated 14 May 1991 will apply to the examination of the Software to facilitate interoperability Licensee agrees to notify Nortel Networks of any such intended examination of the Software and may procure support and assistance from Nortel Networks 7 Term and termination This license is effective until terminated however all of the restrictions with respect to Nortel Networks copyright in the Software and user manuals will cease being effective at the date of expiration of the Nortel Networks copyright those restrictions relating to use and disclosure of Nortel Networks confidential information shall continue in effect Licensee may terminate this license at any time The license will automatically terminate if Licensee fails to comply with any of the terms and conditions of the license Upon termination for any reason Licensee will immediately destroy or return to Nortel Networks the Software user manuals and all copies Nortel Networks is not liable to Licensee for damages in any form solely by reason of the termination of this license 8 Export and re export Licensee agrees not to export directly or indirectly the Software or related technical
202. ply override values for routes that match a BGP announce policy complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens Choose IP The IP menu opens Choose Policy Filters The Policy Filters menu opens Choose BGP 4 The BGP 4 Policies menu opens AJIN Choose Announce Policies The BGP4 Announce Policy Filters window opens Click on the policy that you want to edit The parameter values for that policy appear in the window continued 308628 15 0 Rev 00 5 25 Configuring IP Exterior Gateway Protocols BGP and EGP Site Manager Procedure continued You do this 7 Set the following parameters Advertise Multi Exit Discriminator Multi Exit Discriminator Value Origin Replace As Path Local Preference Override e Local Preference Override Value Override Next Hop Atomic BGP Community to announce BGP Community attribute action As Prepend Click on Help or see the parameter descriptions beginning on pages A 56 Click on Apply and then click on Done System responds You return to the Configuration Manager window 5 26 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies Configuring BGP 4 AS Path Pattern Matching Table 5 7 describes the special charact
203. pology 6 2 308628 15 0 Rev 00 Configuring a Route Reflector Configuring a Single Route Reflector in an AS An IBGP route reflector RR is an IBGP speaker that has established a peer to peer session with an IBGP speaker configured as an RR client You configure an IBGP speaker as a route reflector by establishing a peer to peer session with an RR client You can do this with the BCC or Site Manager Using the BCC To configure an IBGP speaker as a route reflector go to the BGP prompt for example box ip bgp and enter peer local lt reflector_address gt remote lt client_address gt as lt as_number gt reflector_address is the IP address of the local route reflector client_address is the IP address of the remote RR client as_number is an integer identifying the AS in which the remote client is located Because the reflector and the client are located in the same AS BGP recognizes that this is an IBGP session For more information see Chapter 4 Configuring BGP Peers At the session specific prompt enter the following command to specify that the remote client is an internal peer that is located in the same cluster peer mode reflector internal For example the following command sequence defines a peer to peer session between the route reflector 2 2 2 2 and an RR client 2 2 2 3 bgp peer local 2 2 2 2 remote 2 2 2 3 as 2 peer 2 2 2 2 2 2 2 3 peer mode reflector internal peer 2 2 2 2 2 2 2 3 30
204. pplies to EGP advertisements with any gateway address EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 18 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 18 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 18 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters From BGP Peer Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of IP addresses Specifies the IP address of one or more BGP peers This policy applies to BGP advertisements authored by a router on this list and applies only to BGP sourced routes when BGP is included as a route source Specify one or more IP addresses Use the default empty list to indicate that this policy applies to BGP advertisements from any router EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 19 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 19 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 19 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID From BGP Peer AS Configuration Manager gt Protocols gt IP gt Policy Fil
205. pt A 42 AS List Accept A 35 AS Path Override announce A 72 AS Pattern announce A 79 AS Prepend accept A 44 As Prepend announce A 81 AS Weight Class accept A 43 Index 4 Atomic announce A 78 BGP Communities to Match accept A 39 A 44 BGP Communities to Match announce A 73 BGP Communities to match announce A 80 BGP Community attribute action accept A 45 BGP Community attribute action announce A 80 BGP Community to accept accept A 44 BGP Community to announce announce A 79 BGP 3 Route Preference accept A 38 BGP 4 Preference accept A 43 EGP Interface List announce A 69 EGP Metric announce A 69 EGP Peer List announce A 68 Enable accept A 29 Enable announce A 50 External Route Source announce A 68 A 70 A 74 From BGP Peer announce A 65 From BGP Peer AS announce A 66 From EGP Peer announce A 62 From OSPF Router ID announce A 59 From RIP Gateway announce A 57 Gateway List accept A 35 Injection List accept A 36 A 40 Inter AS Metric Selector announce A 71 Local Preference accept A 42 Local Preference Override announce A 77 Local Preference Value announce A 78 Multi Exit Discriminator announce A 75 Multi Exit Discriminator Value announce A 76 Multi Exit Discriminator accept A 46 Multi Exit Discriminator Value accept A 47 Name accept A 30 Name announce A 51 Networks accept A 31 Net
206. pt Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of BGP communities Specifies one or more BGP communities This list identifies which communities are associated with this rule Supply an octet string using the following format each community ID is 4 bytes long 0 in the two most significant bits causes the router to perform the match on the lower 16 bits the default empty list means accept any list 1 3 6 1 4 1 18 3 5 3 2 6 9 1 24 A 44 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters BGP Community attribute action Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies As Is As Is Remove Append Replace Specifies the action to take regarding BGP communities specified in an update Specify one of the following actions e As Is the default leave the existing BGP community attribute unchanged e Remove delete all BGP communities from an update e Append append to the existing BGP communities the list of communities specified in the BGP Community to accept parameter e Replace replace existing BGP communities with those specified in the BGP Community to accept parameter 1 3 6 1 4 1 18 3 5 3 2 6 9 1 25 BGP Route Flap Dampening
207. pt fred 3 34 308628 15 0 Rev 00 Configuring Global BGP Parameters Using Site Manager To create a route flap damping template complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose Policy Filters The Policy Filters menu opens 4 Choose BGP 4 The BGP 4 menu opens 5 Choose Accept Policies The BGP4 Accept Policy Filters window opens 6 Click on Route Flap The Route Flap Dampening List window opens 7 Click on Add The Route Flap Dampening Configuration window opens 8 Set the following parameters Name Cutoff Threshold Reuse Threshold Reachable Decay Unreachable Decay Max HoldDown Memory Limit Click on Help or see the parameter descriptions beginning on page A 47 9 Click on OK You return to the Route Flap Dampening List window 10 Click on Done You return to the BGP4 Accept Policy Filters window 308628 15 0 Rev 00 3 35 Configuring IP Exterior Gateway Protocols BGP and EGP To apply a route flap damping template to an existing BGP accept policy complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols Choose IP The Protocols menu opens The IP menu opens Choos
208. pty list A list of IP addresses Specifies the IP address of one or more EGP gateways This policy applies to EGP advertisements that use these gateways as the next hop Use the default empty list to indicate that this policy applies to EGP advertisements with any gateway address 1 3 6 1 4 1 18 3 5 3 2 6 5 1 12 308628 15 0 Rev 00 A 35 Configuring IP Exterior Gateway Protocols BGP and EGP BGP 3 Specific Accept Policy Parameters Parameter Path Default Options Function Instructions MIB Object ID Injection List Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies An empty list A list of network identifiers Specifies network IDs to be included in the routing table in place of the network IDs listed in the received advertisement Specify a non null value only if the Action parameter is set to Accept The values you enter in the injection list determine the action taken If you supply a list of network IDs or the default network ID 0 0 0 0 0 0 0 0 these IDs are injected into the routing table instead of the actual received IDs If you use the default value an empty list the actual received network IDs are injected into the routing table The Injection List parameter does not perform route aggregation as defined in RFC 1654 To aggregate routes in a transit AS you must construct an announce policy and use the announce Advertise parameter 1 3 6 1 4 1
209. py the associated user manual solely in support of authorized use of the Software by Licensee This license applies to the Software only and does not extend to Nortel Networks Agent software or other Nortel Networks software products Nortel Networks Agent software or other Nortel Networks software products are licensed for use under the terms of the applicable Nortel Networks Inc Software License Agreement that accompanies such software and upon payment by the end user of the applicable license fees for such software 2 Restrictions on use reservation of rights The Software and user manuals are protected under copyright laws Nortel Networks and or its licensors retain all title and ownership in both the Software and user manuals including any revisions made by Nortel Networks or its licensors The copyright notice must be reproduced and included with any copy of any portion of the Software or user manuals Licensee may not modify translate decompile disassemble use for any competitive analysis reverse engineer distribute or create derivative works from the Software or user manuals or any copy in whole or in part Except as expressly provided in this Agreement Licensee may not copy or transfer the Software or user manuals in whole or in part The Software and user manuals embody Nortel Networks and its licensors confidential and proprietary intellectual property Licensee shall not sublicense assign or otherwise disclose to any third pa
210. r to function 1 3 6 1 4 1 18 3 5 3 2 4 3 1 6 A 26 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Enable Configuration Manager gt Protocols gt IP gt EGP gt Neighbors gt EGP Neighbor Enable Enable Disable Enables or disables an EGP neighbor relationship with the specified IP address Set this parameter to Disable if you want to temporarily disable this neighbor relationship rather than delete it Or set it to Enable if you previously disabled this neighbor relationship and now want to reenable it 1 3 6 1 4 1 18 3 5 3 2 4 3 1 2 Acquisition Mode Configuration Manager gt Protocols gt IP gt EGP gt Neighbors gt EGP Neighbor Passive Passive Active Specifies which of the two neighbors initiates EGP connections The router in the active mode is the initiator Set this parameter to Active if you want the local EGP neighbor to be the initiator of EGP connections Otherwise accept the default value Passive 1 3 6 1 4 1 18 3 5 3 2 4 3 1 7 Poll Mode Configuration Manager gt Protocols gt IP gt EGP gt Neighbors gt EGP Neighbor Both Active Passive Both Specifies the type of neighbor reachability algorithm that this local EGP neighbor
211. rameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Outbound Peers Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies An empty list A list of IP numbers Specifies the IP address of one or more BGP peers If a BGP peer is included in this list this policy applies to BGP advertisements being sent to that peer Specify one or more IP addresses Configure an empty list to indicate that this policy applies to BGP advertisements being sent to any peer 1 3 6 1 4 1 18 3 5 3 2 6 8 1 23 Inter AS Metric Selector Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies None None Specified Originating Indicates whether or not an inter AS metric is to be advertised for a network matching this policy and if advertised what value to use Select None to indicate that no metric is to be advertised Select Specified to indicate that the value you specify in the Specific Inter AS Metric parameter is to be used Select Originating to indicate that the metric from the originating protocol will be used This parameter is valid only if the Action parameter is set to Announce 1 3 6 1 4 1 18 3 5 3 2 6 8 1 24 308628 15 0 Rev 00 A 71 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path
212. rasmine a aE S ea 7 6 Figure 8 1 EGP Connection Between Two Autonomous Systems Running RIP 8 2 308628 15 0 Rev 00 xi Tables Table 1 1 BGP 3 Path Aves sosro 1 9 Table 1 2 BGP 4 Mandatory Path Attributes 0 0 0 eccccceeeeeseeeeeteeeeeeeeeeseeeeeaaeeeeaes 1 9 Table 1 3 BOP 4 Optional Path ANDUIES asscctccctescciccctnteaiocectameccicecamdelidaniendietonmte 1 10 Table 3 1 Route Types for BGP Advertisement ccccsssscessseceeeeeseseseeeeessenaeess 3 8 Table 3 2 Slot Mask Parameter Values sancsccccisnonscciinnnedcnsdnnosdacdsnnnssecddsnnnoedadsnnnnocadan 3 16 Table 3 3 Black Hole Punching Parameter Settings cccccssessseeeeseeeeeeeeeees 3 19 Table 3 4 Best Route Selection Rules caves ccsinspotussisier case naaa inie 3 27 Table 3 5 Local Preference Calculation Method c cesceeceseeceeeeeeeeeeeeeeeeeeeeeees 3 28 Table 3 6 Route Flap Damping Template Parameters ccsscccceeesseeeeeeeneeees 3 33 Table 4 1 MD5 Signature Verification Rules on BGP TCP Packets 000 4 25 Table 5 1 BCC Definition Parameters for BGP Accept Policies cceeeeee 5 4 Table 5 2 BCC Match Parameters for BGP Accept Policies scceceteeeeeeeeees 5 7 Table 5 3 BCC Modification Parameters for BGP Accept Policies cce 5 10 Table 5 4 BCC Definition Parameters for BGP Announce Policies 0 5 14 Table 5 5 BCC Match Parameters for BGP Announce Polic
213. reenable loop detection complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to The parameters for that peer appear in edit parameters the window continued 4 20 308628 15 0 Rev 00 Configuring BGP Peers Site Manager Procedure continued You do this System responds 8 Set the Loop Detection parameter Click on Help or see the parameter description on page A 17 9 Click on Apply and then click on Done You return to the IP Interface List for BGP window Configuring Peers over an Unnumbered Point to Point Link You cannot configure a BGP peer to peer session directly on an unnumbered interface To establish a connection each side of the connection must be associated with a numbered interface For example consider the two routers in Figure 4 2 Routers A and B are connected by a point to point network using unnumbered interfaces Both routers are configured with BGP Peer to Peer connection Network 1 Network 3 Point to P
214. rns you to the Configuration Manager window 308628 15 0 Rev 00 2 7 Chapter 3 Configuring Global BGP Parameters You customize global BGP parameters for your AS as described under the following topics Topic Page Disabling and Reenabling BGP 3 2 Supplying a BGP Router ID 3 4 Identifying the Local AS 35 Disabling and Reenabling IBGP Support 3 6 Specifying Route Types for IBGP Advertisements 3 7 Enabling BGP Interaction with OSPF and RIP 3 9 Setting the Update Interval Timer 3 10 Allowing Redundant Connections 3 11 Enabling Multihop Connections 3 13 Disabling and Reenabling Dynamic Policy Configuration 3 15 Configuring the BGP Soloist Slot Mask 3 16 Disabling and Reenabling Route Aggregation 3 17 Enabling and Disabling Black Hole Punching 3 18 Disabling and Reenabling the BGP 4 MED Attribute 3 20 Configuring BGP 4 Confederations 3 21 Disabling BayRS Local Preference Calculation and Route Selection 3 25 Configuring BGP Message Logging 3 29 Configuring EBGP Route Flap Damping 231 Assigning Weight Classes and Values to an AS 2 37 308628 15 0 Rev 00 3 1 Configuring IP Exterior Gateway Protocols BGP and EGP Disabling and Reenabling BGP When you start BGP on the router BGP is automatically enabled for both BGP 3 and BGP 4 peer to peer connections You can use the BCC and Site Manager to disable and reenable BGP 4 on the router You can also u
215. rocedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the BGP Intra AS parameter Click on Help or see the parameter description on page A 5 6 Click on OK You return to the Configuration Manager window Specifying Route Types for IBGP Advertisements If IBGP is enabled you can specify the types of routes that BGP advertises in IBGP sessions By default IBGP propagates only routes learned from external BGP peers You can use the BCC or Site Manager to configure IBGP to propagate routes learned from all route sources excluding IBGP and OSPF interarea and intra area routes which IBGP never advertises 308628 15 0 Rev 00 3 7 Configuring IP Exterior Gateway Protocols BGP and EGP Using the BCC To specify the types of routes that IBGP advertises go to the BGP prompt for example box ip bgp and enter redistribute protocols lt protocols gt protocols is one of the values listed in Table 3 1 Table 3 1 Route Types for BGP Advertisements Route Type Meaning bgp default all BGP propagates routes from all route sources BGP propagates routes learned from external BGP peers For example the following command configures BGP to advertise routes from all route s
216. roduct from a distributor or authorized reseller contact the technical support staff for that distributor or reseller for assistance If you purchased a Nortel Networks service program contact one of the following Nortel Networks Technical Solutions Centers Technical Solutions Center Telephone 33 4 92 966 968 800 4NORTEL or 800 466 7835 61 2 9927 8800 800 810 5000 Europe Middle East and Africa North America Asia Pacific China An Express Routing Code ERC is available for many Nortel Networks products and services When you use an ERC your call is routed to a technical support person who specializes in supporting that product or service To locate an ERC for your product or service go to the www12 nortelnetworks com URL and click ERC at the bottom of the page 308628 15 0 Rev 00 xxi Chapter 1 Exterior Gateway Protocols BGP and EGP This chapter introduces the concepts and terminology used in this guide Topic Page Autonomous Systems and Gateway Protocols 1 1 BGP Concepts and Terminology 1 4 BGP Implementation Notes 1 12 Autonomous Systems and Gateway Protocols LANs and WANs interconnected by IP routers form a group of networks called an internetwork For administrative purposes an internetwork is divided into autonomous systems An autonomous system AS is a group of routers called gateways in IP terminology and hosts
217. rough 480 seconds 1 3 6 1 4 1 18 3 5 3 2 4 3 1 10 A 28 308628 15 0 Rev 00 Site Manager Parameters Routing Policy Parameters Topic Page Accept Policies Common Accept Policy Parameters A 29 EGP Specific Accept Policy Parameters A 34 BGP 3 Specific Accept Policy Parameters A 36 BGP 4 Specific Accept Policy Parameters A 40 Announce Policies Common Announce Policy Parameters A 50 EGP Specific Announce Policy Parameters A 68 BGP 3 Specific Announce Policy Parameters A 70 BGP 4 Specific Announce Policy Parameters A 74 Common Accept Policy Parameters Parameter Enable Path Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Accept Policies Path Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Accept Policies Path Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies Default Enable Options Enable Disable Function Enables or disables this policy Instructions Set to Disable to disable the policy MIB Object ID EGP 1 3 6 1 4 1 18 3 5 3 2 6 5 1 2 MIB Object ID BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 7 1 2 MIB Object ID BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 9 1 2 308628 15 0 Rev 00 A 29 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Obje
218. route should be suppressed 1 3 6 1 4 1 18 3 5 3 2 5 1 8 1 8 308628 15 0 Rev 00 A 49 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Memory Limit Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies gt Route Flap 45 1 to 60 minutes Specifies the maximum amount of time that the status of a route can remain unchanged reachable or unreachable before BGP unsuppresses the route If the status of the route remains unchanged after the number of minutes you specify BGP unsuppresses the route and sets the penalty value to 0 Enter the maximum amount of time in minutes that the status of a route can remain unchanged reachable or unreachable If the status of the route remains unchanged for the specified number of minutes BGP resets the penalty value and flap count to 0 If the route is currently suppressed BGP unsuppresses it 1 3 6 1 4 1 18 3 5 3 2 5 1 8 1 9 Common Announce Policy Parameters Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Enable Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy
219. routes from other protocols and possibly included in the forwarding table This chapter covers the following topics Topic Page Configuring a BGP Accept Policy 5 2 Configuring a BGP Announce Policy 5 13 Configuring BGP 4 AS Path Pattern Matching 5 27 Configuring a BGP Accept Policy BGP accept policies determine which routes BGP submits to the IP routing table manager To configure a new BGP accept policy you must do the following e Supply a name for the accept policy Specify whether BGP ignores or accepts an update that matches the policy Rank the policy according to preference precedence and BGP weight class You can use the BCC or Site Manager to define BGP accept policies You can configure up to 32 BGP accept policies 5 2 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies Using the BCC To create a BGP accept policy go to the BGP prompt for example box ip bgp and enter accept lt policy_name gt policy_name is a unique name for the BGP accept policy For example the following command creates a BGP accept policy named accept_pol_1 bgp accept accept_pol_1 accept accept_pol_1 bgp To customize the default values for the policy enter lt parameter gt lt value gt Table 5 1 lists the parameters and values that you can enter 308628 15 0 Rev 00 5 3 Configuring IP Exterior Gateway Protocols BGP and EGP Table 5 1 BCC Definition Param
220. rror 6 10 Chapter 7 Configuring Route and Traffic Balancing Configuring IBGP for Route and Traffic Balancing ccccceesseeceeeeeeeeeeeeeeeeeeeeaeeeteneeees 7 1 Configuring EBGP for Route and Traffic Balancing a ssisiesssi snadne aniani 7 5 Chapter 8 Customizing EGP Services EGP Concepis and Ter ra rusras ahead ante aaiaeoatieads 8 2 EGP Mmpiemematon Noes oi sacecccsiecoremssatosctonaicesestitesnapeateeeenied tauansben Resets iatomeomiested 8 5 Customizing EGP n Me ROEI rooien anerian a a EAEE 8 6 Ea ee anrd CON EGP asiriarren iaia aE SAE A 8 6 Supping a Local AS NUMOGI nisasie e A 8 7 Oss CITA ep a 6 802 arara T Ea 8 7 Specifying the Neighbor s Address c cccccccceseseeeeeeeeceaeeeeeneeeeaaeseeeneesteaeeteeneeeeaas 8 8 Speciing ihe Ata ModE acta iccs cascciccciaies dcenanseeinacdateedacadomnedicuediisdstadaueeactetentess 8 9 Enabling and Disabling the Neighbor Relationship cceeeeeeeeeeeeeeeeeeeeeeeeeeees 8 10 Choosing the Acquisition Mode iiccccecsacccncviacansedsanane ons idannadecansdarnacsiaminnnesianeasesanaiens 8 11 Choosing the al AS serisinin ir eee aaea cater 8 12 Seting Neighbor TIMETE surunsa aaa iiS 8 13 Appendix A Site Manager Parameters BEF PAIT IER a R AEA E NNA A 2 BOP Coniguration Paramietdis 25 5 sccosegent caviaassuctiiadardcssedanesinadetiaasende igloos A 3 BGP Global Parameters soriire ar a ai A 4 BGFP JF OVDA Parameter oonan aa a A 11 BGPA Global PIameter srno eer rrerr reer eer meer reer
221. rty the Software or any information about the operation design performance or implementation of the Software and user manuals that is confidential to Nortel Networks and its licensors however Licensee may grant permission to its consultants subcontractors and agents to use the Software at Licensee s facility provided they have agreed to use the Software only in accordance with the terms of this license 3 Limited warranty Nortel Networks warrants each item of Software as delivered by Nortel Networks and properly installed and operated on Nortel Networks hardware or other equipment it is originally licensed for to function substantially as described in its accompanying user manual during its warranty period which begins on the date Software is first shipped to Licensee If any item of Software fails to so function during its warranty period as the sole remedy Nortel Networks will at its discretion provide a suitable fix patch or workaround for the problem that may be included in a future Software release Nortel Networks further warrants to Licensee that the media on which the Software is provided will be free from defects in materials and workmanship under normal use for a period of 90 days from the date Software is first shipped to Licensee Nortel Networks will replace defective media at no charge if it is returned to Nortel Networks during the warranty period along with proof of the date of shipment This warranty does not apply if the med
222. run by a single technical administrator that has a single clearly defined routing policy Each autonomous system has its own unique AS number assigned by the appropriate Internet Registry entity Figure 1 1 shows a sample internetwork segmented into three autonomous systems 308628 15 0 Rev 00 1 1 Configuring IP Exterior Gateway Protocols BGP and EGP Autonomous system 2 Figure 1 1 Router 1 Autonomous system 3 Router Autonomous 8 system 1 Router 7 IP0006B Internetwork Segmented into Three Autonomous Systems The routers at the edges or borders of autonomous systems are called gateways These gateways use exterior gateway protocols to exchange reachability information and to route packets between routing domains 1 2 308628 15 0 Rev 00 Exterior Gateway Protocols BGP and EGP Border Gateway Protocol BGP The Border Gateway Protocol BGP is an exterior gateway protocol used by border routers to exchange network reachability information with other BGP systems BGP routers form peer relationships with other BGP routers in other autonomous systems or within the same autonomous system BGP peers trans
223. s Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on Add The BGP Peer window opens 8 Set the following parameters Peer Address Peer AS e Local Address Click on Help or see the parameter descriptions beginning on page A 11 9 Set the Peer Mode parameter to None the default value 10 Click on OK You return to the BGP Peer List window 11 Click on Apply and then click on Done You return to the IP Interface List for BGP window 308628 15 0 Rev 00 6 11 Chapter 7 Configuring Route and Traffic Balancing BGP route balancing and traffic balancing are two techniques that allow a BGP speaker to distribute routes to the same destination among multiple equal cost paths This chapter describes how to configure route and traffic balancing for IBGP and EBGP In both techniques BGP uses equal cost multipath ECMP routes submitted to the IP routing table by the IGP OSPF or RIP in the AS The ECMP routes could also be static routes For information about configuring ECMP for OSPF and RIP see Configuring IP ARP RARP
224. s From OSPF Router ID Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of IP addresses Specifies the IDs of one or more OSPF routers This policy applies to OSPF advertisements authored by a router on this list and applies only to OSPF sourced routes when OSPF is included as a route source Specify one or more IP addresses Use the default empty list to indicate that this policy applies to OSPF updates from any router EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 13 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 13 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 13 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Received OSPF Type Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies Any Typel Type2 External Internal Any Specifies which types of OSPF routes match this policy and appl
225. s 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens continued 308628 15 0 Rev 00 Configuring Global BGP Parameters Site Manager Procedure continued You do this System responds 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the Detect Redundant Connections parameter Click on Help or see the parameter description on page A 7 6 Click on OK You return to the Configuration Manager window Enabling Multihop Connections By default BGP enforces the one hop rule for BGP peers the remote peer must be located on a directly attached network You can use the BCC or Site Manager to override the restriction and allow multihop connections Caution Enabling multihop BGP connections can cause EBGP speakers to establish a BGP connection that traverses a third party AS which may violate policy considerations and may also introduce forwarding loops Using the BCC To override the one hop rule and allow multihop connections go to the BGP prompt for example box ip bgp and enter multi hop lt state gt state is either enabled or disabled default For example the following command enables BGP for multihop peer connections bgp multi hop enabled bgp 308628 15 0 Rev 00 3 13 Configuring IP Exterior Gateway Protocols BGP and EGP
226. s are the same prefer the path with the lowest MED attribute If the paths have the same MED prefer the external path over the internal path If the paths are still the same prefer the path through the closest IGP neighbor Prefer the path with the lowest IP address as specified by the BGP router ID 1 2 10 Choose the route with the lower route weight Choose the route with the higher local preference attribute If the BGP global parameter local pref calculation is disabled nondefault the LP of routes is set to 100 unless a policy overrides this value Choose the route with the shortest AS path Choose the route with the smallest ORIGIN IGP lt EGP lt INCOMPLETE Choose the route with the lower multiexit discriminator attribute routes without a MED are assumed to have a max MED Choose the route with the lower interior cost to the next hop Choose external BGP over IBGP Choose the route with the lower BGP identifier Choose the route with the lower BGP connection remote address Choose the route with the lower BGP connection local address 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Regular Expression Symbols Table B 4 lists the characters used in Cisco and Nortel Networks regular expressions Table B 4 Regular Expression Symbols Name Symbol Meaning Period Matches any single character including white space Asterisk
227. se Site Manager to disable and reenable BGP 3 and BGP 4 Note BGP will not operate with an IP router in not forwarding host only mode Make sure that the routers you want BGP to operate with are in forwarding mode For instructions on configuring the router for forwarding mode see Configuring IP ARP RARP RIP and OSPF Services Using the BCC To disable and reenable BGP go to the BGP prompt for example box ip bgp and enter state lt state gt state is either enabled default or disabled For example the following command disables BGP bgp state disabled Using Site Manager To disable and reenable BGP complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens continued 3 2 308628 15 0 Rev 00 Configuring Global BGP Parameters Site Manager Procedure continued You do this 5 Set the BGP Enable parameter Click on Help or see the parameter description on page A 4 System responds 6 Click on OK You return to the Configuration Manager window 7 Inthe Configuration Manager window The Protocols menu opens choose Protocols 8 Choose IP The IP menu opens 9 Choose BGP The BGP menu opens
228. t IP gt Policy Filters gt BGP 4 gt Accept Policies gt Route Flap 5 1 to 45 minutes Specifies the amount of time in minutes before BGP decrements the penalty value of a reachable route by half BGP uses a half life decay algorithm to decrement the penalty value Enter a value for the half life decay for reachable routes 1 3 6 1 4 1 18 3 5 3 2 5 1 8 1 6 A 48 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Unreachable Decay Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies gt Route Flap 15 1 to 45 minutes Specifies the amount of time in minutes before BGP decrements the penalty value of an unreachable route by half BGP uses a half life decay algorithm to decrement the penalty value Enter a value for the half life decay for an unreachable route 1 3 6 1 4 1 18 3 5 3 2 5 1 8 1 7 Max HoldDown Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies gt Route Flap 45 1 to 60 minutes Specifies the maximum amount of time that a route can remain suppressed If the route remains suppressed after the number of minutes you specify BGP unsuppresses it even if the penalty value exceeds the threshold Enter the maximum amount of time in minutes that the
229. t already knows to be reachable The poll message requests routing information from the passive neighbor e The routing update response contains the routing information the list of gateways on the common network the networks they can reach and associated distances Both active and passive neighbors can send routing update messages The active neighbor usually sends a routing update response after it sends a poll message The passive neighbor usually sends a routing update response in response to a poll message 8 4 308628 15 0 Rev 00 Customizing EGP Services EGP Implementation Notes This section provides you with some important guidelines to follow when you configure EGP If you do not follow these guidelines EGP will become disabled on the interfaces involved Autonomous system numbers must be from 1 through 65 535 Two autonomous systems connected by an EGP link must have different autonomous system numbers The remote IP address cannot be the same as any local IP interface address The remote IP address must be on the same subnet as one of the local IP interfaces EGP does not have any loop avoidance techniques avoid loop topologies otherwise you will have to configure EGP route filters to counter the redundancies An EGP configuration between two ASs each using a subnetted interface to a class A network results in a routing black hole RIP Version 1 aggregates the single subnet into the natural network but
230. te Manager To configure a confederation complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens Choose IP The IP menu opens 3 Choose BGP 4 Choose BGP Global The BGP menu opens The Edit BGP Global Parameters window opens Set the following parameters Confederation ID Confederation Peer Click on Help or see the parameter descriptions beginning on page A 10 Click on OK You return to the Configuration Manager window 3 24 308628 15 0 Rev 00 Configuring Global BGP Parameters Disabling BayRS Local Preference Calculation and Route Selection A BGP speaker calculates a local preference value for each route that it receives from an external peer and passes this value as the local_pref attribute in routing updates that it announces to its internal BGP IBGP peers A BGP speaker that receives a routing update from an IBGP peer uses the local_pref attribute in its best route selection process By default BGP calculates a local preference value by using the algorithm described in Calculating BGP 4 Local Preference Values on page 3 25 The best route selection process is described in Best Route Selection on page 3 27 Different implementations of BGP use different methods of arriving at a local preference value However within
231. te echo enabling and disabling for BGP 4 18 route flap damping 3 31 route reflector IBGP configuring 6 1 described 1 7 router ID BGP 3 4 308628 15 0 Rev 00 RR client BGP 6 10 S soloist configuring slots for BGP 3 16 starting BGP with Site Manager 2 3 BGP with the BCC 2 1 EGP 2 6 IP 2 3 static black hole routes definition 3 18 supernet defining black hole for 3 18 support Nortel Networks xxi T Tcp Authentication BGP parameter A 18 Tcp Authentication parameter A 18 Tcp Md5 Key BGP parameter A 20 Tcp Md5 Key Storage BGP parameter A 19 technical publications xx technical support xxi text conventions xvi traffic balancing described 1 8 EBGP 7 5 IBGP 7 1 transit AS 1 6 TTL time to live BGP 4 16 U update size maximum for BGP 4 15 W Weight Value parameter 3 38 A 20 Index 5
232. tection key NPK MEK value before you set the MDS authentication parameters For information about the Technician Interface secure shell see Configuring IPsec Services 308628 15 0 Rev 00 4 25 Configuring IP Exterior Gateway Protocols BGP and EGP Using the BCC To set the BGP 4 authentication parameters go to the BGP peer prompt for example box ip bgp peer 2 2 2 2 3 3 3 3 and enter tcp authentication lt state gt state is either none default or md5 For example the following command enables BGP 4 MD5 authentication on peer session 2 2 2 2 3 3 3 3 peer 2 2 2 2 3 3 3 3 tcp authentication md5 peer 2 2 2 2 3 3 3 3 If you do not enable TCP authentication the other BGP authentication parameters are irrelevant After you enable MD5 authentication you can configure the other BGP 4 authentication parameters At the peer prompt enter tcp md5 key lt key gt key is the value assigned to the MD5 key no default For example the following command sets the BGP 4 MDS key to corpkey peer 2 2 2 2 3 3 3 3 tep md5 key corpkey peer 2 2 2 2 3 3 3 3 You also can specify whether to store the key as clear text or encrypted At the peer prompt enter tcp md5 key storage lt format gt format is either clear text default or encrypted For example the following command sets the BGP 4 MDS key storage format to encrypted peer 2 2 2 2 3 3 3 3 tcep md5 key storage encrypted peer 2 2 2 2 3 3 3 3 4 26
233. ters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of autonomous system numbers Specifies one or more autonomous system numbers This policy applies to BGP advertisements received from BGP peers in an AS on this list and applies only to BGP sourced routes when BGP is included as a route source Specify one or more AS numbers Use the default empty list to indicate that this policy applies to BGP advertisements from peers in any AS EGP 1 3 6 1 4 1 18 3 5 3 2 6 6 1 20 BGP 3 1 3 6 1 4 1 18 3 5 3 2 6 8 1 20 BGP 4 1 3 6 1 4 1 18 3 5 3 2 6 10 1 20 A 66 308628 15 0 Rev 00 Parameter Path Path Path Default Options Function Instructions MIB Object ID MIB Object ID MIB Object ID Site Manager Parameters Received BGP Next Hop Configuration Manager gt Protocols gt IP gt Policy Filters gt EGP gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 3 gt Announce Policies Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Announce Policies An empty list A list of IP addresses Specifies one or more IP addresses This policy applies to BGP advertisements whose Next Hop attribute matches an IP address on this list and app
234. th Default Options Function Instructions MIB Object ID Aggregator AS List Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of AS numbers Specifies one or more autonomous systems This policy applies to BGP advertisements that contain in their Aggregator path attribute an AS number on this list To specify that the policy applies to BGP advertisements with any AS number in the Aggregator path attribute use the default empty list 1 3 6 1 4 1 18 3 5 3 2 6 9 1 14 Aggregator Router List Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies An empty list A list of IP addresses Specifies one or more BGP routers This policy applies to BGP advertisements that contain in their Aggregator path attribute an IP address on this list To specify that this policy applies to BGP advertisements with any router address in the Aggregator path attribute use the default empty list 1 3 6 1 4 1 18 3 5 3 2 6 9 1 15 Local Preference Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies 0 0 to 2147483647 Assigns a local preference value to a route matching this policy This value overrides the calculated value for EBGP routes or the Local Preference path attribute for IBGP routes To indicate a preference enter a value from 1 through 2147483647 1 3 6 1 4 1 18 3 5 3 2 6
235. th RFC 2385 Protection of BGP Sessions via the TCP MDS Signature Option When BGP authentication is enabled a BGP speaker can verify that the BGP messages it receives from its peers are actually from a peer and not from a third party masquerading as a peer See Configuring and Enabling MD5 Authentication on page 4 22 for a detailed description of this feature and for configuration information 308628 15 0 Rev 00 1 11 Configuring IP Exterior Gateway Protocols BGP and EGP BGP Implementation Notes The following guidelines are crucial to successful BGP configuration Caution If you do not follow these guidelines BGP either will not work efficiently or will become disabled on the interfaces involved e BGP will not operate with an IP router in nonforwarding host only mode Make sure that the routers you want BGP to operate with are in forwarding mode For instructions on setting the forwarding mode see Configuring 1P ARP RARP RIP and OSPF Services e If you are using BGP for a multihomed AS one that contains more than one exit point Nortel Networks strongly encourages you to use OSPF for your IGP and BQP for your sole exterior gateway protocol or use intra AS IBGP routing For information about configuring OSPF see Configuring IP ARP RARP RIP and OSPF Services e If OSPF is the IGP you should use the default OSPF tag construction Using EGP or modifying the OSPF tags makes network administration
236. the gateway router does not have complete subnet information or a natural network route to match the one being advertised by RIP Version 1 This black hole is not an EGP or RIP defect rather it is caused by the way RIP aggregates subnets into natural networks EGP will operate over a subnetted interface between two Nortel Networks routers if a static route is implemented The router accepting the subnet from the remote network must augment the single subnet information with a static route for the entire remote network 308628 15 0 Rev 00 8 5 Configuring IP Exterior Gateway Protocols BGP and EGP Customizing EGP on the Router You customize EGP on the router by setting EGP global parameters as described under the following topics Topic Page Enabling and Disabling EGP 8 6 Supplying a Local AS Number 8 7 Enabling and Disabling EGP When you start EGP on the router EGP is automatically enabled for operation To disable and reenable EGP complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens 2 Choose IP The IP menu opens 3 Choose EGP The EGP menu opens 4 Choose Global The Edit EGP Global Parameters window opens 5 Set the Enable parameter Click on Help or see the parameter description on page A 25 6 Click on OK You
237. tion parameter is set to Accept Specify one of the following values e Passthru default the value will be advertised as received e Override the value of the Multi Exit Discriminator parameter will be used e Generate the value of the Multi Exit Discriminator parameter will be used if a MED attribute is not present in the BGP 4 update message e Delete the MED metric will be removed if present in the attribute list 1 3 6 1 4 1 18 3 5 3 2 6 9 1 27 A 46 308628 15 0 Rev 00 Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Site Manager Parameters Multi Exit Discriminator Value Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies 1 1 0 or a positive number Specifies the value to use as the multiexit discriminator This parameter is valid only if the Action parameter value is Accept and if the Multi Exit Discriminator parameter is set to Override or Generate and there is a MED present in the update Enter the MED value 1 3 6 1 4 1 18 3 5 3 2 6 9 1 22 Name Configuration Manager gt Protocols gt IP gt Policy Filters gt BGP 4 gt Accept Policies gt Route Flap None An alphanumeric string up to 20 characters Identifies the name of the route flap dampening te
238. tisements with the origin path that you specify aggregator as List of AS numbers Specifies an autonomous system This policy applies to BGP advertisements with this AS number in the aggregator path attribute aggregator router List of IP addresses Specifies a BGP router This policy applies to BGP advertisements with this IP address in the aggregator path attribute no advertise no export subconfed List of BGP communities as List of AS numbers Specifies an AS This policy applies to BGP advertisements from peers in this AS community no export Specifies a BGP community This policy applies to all BGP advertisements that match one or more members of the community list Specify one of the well known community names no export no advertise no export subconfed or enter a four octet community number in the form AS_number value Entering 0 in the two most significant bits causes the router to match on the lower 16 bits continued 308628 15 0 Rev 00 5 7 Configuring IP Exterior Gateway Protocols BGP and EGP Table 5 2 BCC Match Parameters for BGP Accept Policies continued Parameter Values Function network List of IP addresses Specifies the networks that match this policy Each specification consists of a network IP address a mask and a flag exact or range to indicate whether the network address refers to a specific network or to a range of networks Enter a
239. to reenable it 1 3 6 1 4 1 18 3 5 3 2 5 1 3 1 2 308628 15 0 Rev 00 A 23 Configuring IP Exterior Gateway Protocols BGP and EGP BGP Event Message Parameters Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Peer Local Remote Configuration Manager gt Protocols gt IP gt BGP gt BGP Debug 0 0 0 0 0 0 0 0 The IP addresses for the BGP local peer and remote peer Specifies the IP address of the BGP local peer and the remote peer To obtain event messages about all connections between all BGP peers accept the default value 0 0 0 0 0 0 0 0 Enter a specific pair of IP addresses to obtain event messages about connections between the peers with that IP address combination To limit the application of the debug attributes to the BGP 4 gateway connections enter 255 255 255 255 for the remote IP address 1 3 6 1 4 1 18 3 5 3 2 5 1 5 1 2 Message Level Configuration Manager gt Protocols gt IP gt BGP gt BGP Debug All All Debug Info Warning Fault Trace Specifies the severity level of event messages received Accept the default to obtain event messages of all levels To select one or more levels click on Values 1 3 6 1 4 1 18 3 5 3 2 5 1 5 1 4 Message Trace Switch Configuration Manager gt Protocols gt
240. to the BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter ebgp ecmp method lt method gt method is one of the values shown in Table 7 2 Table 7 2 EBGP ECMP Methods Method Meaning route balance BGP submits one BGP route to the IP routing table for each BGP destination using in turn round robin the available ECMP routes to the next hop traffic balance BGP submits multiple routes to IP using all known ECMP IP next hops disabled default BGP implements neither route nor traffic balancing For example the following sequence of BCC commands does the following 1 Configures an IP circuitless virtual interface 201 1 1 1 on the local router s virtual circuit 2 Configures two static routes to destination 201 1 1 4 the IP virtual interface on the remote router Assigns router ID 201 1 1 1 to BGP on the local router Associates local BGP with AS 11 Configures local BGP for multihop peer to peer sessions Nn eA DBW Establishes a BGP peer to peer session between virtual interface 201 1 1 1 on the local router and virtual interface 201 1 1 4 on the remote router 7 Configures the peer to peer session for route balancing box Virtual virtual ip address 201 1 1 1 mask 255 255 0 0 ip 201 1 1 1 255 255 0 0 box box ip ip static route 201 1 1 4 30 198 2 1 1 static route 201 1 1 4 255 255 255 252 198 2 1 1 back ip static route 201 1 1 4 30 192 32 28 51 static rout
241. traffic balancing bgp ibgp ecmp method traffic balance bgp 7 4 308628 15 0 Rev 00 Configuring Route and Traffic Balancing Using Site Manager To configure IBGP for ECMP route or traffic balancing complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the IBGP ECMP Method parameter Click on Help or see the parameter description on page A 9 6 Click on OK You return to the Configuration Manager window Configuring EBGP for Route and Traffic Balancing EBGP route balancing and traffic balancing are two techniques that allow an EBGP speaker to distribute routes to the same destination among multiple equal cost paths In both techniques EBGP uses equal cost multipath ECMP routes submitted statically to the IP routing table Although unusual for EBGP connections the ECMP routes could also be submitted by OSPF or RIP For information about configuring ECMP for OSPF and RIP see Configuring IP ARP RARP RIP and OSPF Services You can configure an EBGP speaker to use ECMP static routes in the IP routing table for route balancing and traffic balancing 308628 15 0 Rev 00 7 5 Configuring IP Exterior Gateway Protocols BGP and E
242. two networks 192 32 1 0 and 192 32 2 0 are both reachable by two paths The first path to each network shares a common AS AS 5 The second path to each network also shares a common AS AS 10 If you want to favor AS 5 in the path to 192 32 1 0 and AS 10 in the path to 192 32 2 0 you can assign one weight class to AS 5 in the path to network 192 32 1 0 and another class to AS 5 in the path to 192 32 2 0 When a BGP router receives a new route it evaluates the route against any existing accept policies If after this evaluation the path still is to be used the router calculates the total weight of the path Configure the same AS weights on all BGP routers in an AS You can use Site Manager to assign a weight and a weight class to an AS by completing the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Weights The BGP AS Weight Parameters window opens 5 Click on Add The BGP AS Weights window opens continued 308628 15 0 Rev 00 3 37 Configuring IP Exterior Gateway Protocols BGP and EGP Site Manager Procedure continued You do this System responds 6 Set the following parameters e AS Weight Value 1 through 8 Click on Help or see the parameter descriptions beginning on page A 20 7 Click
243. tworks BCC 1 no synchronization default behavior 2 route reflector route reflector 3 bgp damping bgp damping 4 confederation confederation 5 not supported collision detection BGP Monitoring Commands Item Cisco Nortel Networks BCC 6 show ip bgp show bgp routes 7 show ip bgp neighbors show bgp peers 8 show ip bgp neighbors show bgp timers 9 show ip bgp neighbors show bgp routes N 10 show ip bgp neighbors 1 1 1 2 show bgp routes p1 1 1 2 11 show ip bgp regexp 123 456 show bgp routes R 123 456 12 show ip bgp summary show bgp summary 13 clear ip bgp ip bgp peer local ip neighbor ip neighbor ip address state disabled state enabled 14 debug ip bgp updates log eBGP p 15 debug ip bgp events show bgp errors 16 show ip route show ip routes 17 trace 1 1 1 1 ping p 1 1 1 1 B 8 308628 15 0 Rev 00 Converting Cisco to Nortel Networks Equivalents Interpreting the Operational Commands Table The following list describes the functions of the Cisco and Nortel Networks BCC operational commands in the corresponding row of Table B 2 1 10 11 12 13 14 15 16 Do not synchronize between BGP and IGP this enables a router to advertise a BGP network to an external peer without having that network exist in the IP routing table Route reflection is a method for alleviating the need for full mesh IBGP by allowing an internal BGP speaker to reflect or readvertise
244. u can use the BCC or Site Manager to specify how often BGP issues a keepalive message on this peer to peer session or to disable the keepalive function by setting the value to 0 Using the BCC To set the keepalive interval go to a BGP peer prompt for example box ip bgp peer 2 2 2 2 2 2 2 3 and enter keepalive lt seconds gt seconds specifies how often BGP sends a keepalive message from 1 through 2 147 483 647 on this peer session Setting this value to 0 disables the sending of keepalive messages For example the following command causes BGP to send a keepalive message every 10 seconds on interface 2 2 2 2 to the peer at 2 2 2 5 peer 2 2 2 2 2 2 2 5 5 keepalive 10 peer 2 2 2 2 2 2 2 5 5 Using Site Manager To set the keepalive interval complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose Peers The IP Interface List for BGP window opens continued 4 8 308628 15 0 Rev 00 Configuring BGP Peers Site Manager Procedure continued You do this System responds 5 Click on the IP interface for which you want to edit BGP peer parameters 6 Click on BGP Peers The BGP Peer List window opens 7 Click on the peer for which you want to The parameters for that peer appear
245. u do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens Choose IP The IP menu opens Choose Policy Filters The Policy Filters menu opens Choose BGP 4 The BGP 4 Policies menu opens ay oO Choose Accept Policies Click on the policy for which you want to specify matching criteria The BGP4 Accept Policy Filters window opens The parameter values for that policy appear in the window Set the following parameters e Networks e Peer As Peer Address Originating As Route Origin Aggregator As List Aggregator Router List As Pattern BGP Communities to match Click on Help or see the parameter descriptions beginning on page A 31 Click on Apply and then click on Done You return to the Configuration Manger window 308628 15 0 Rev 00 5 9 Configuring IP Exterior Gateway Protocols BGP and EGP Supplying Modification Values for a BGP Accept Policy You can use the BCC or Site Manager to specify override values for fields in routing updates that match the BGP accept policy Using the BCC To supply values that BGP can use to modify attributes in a BGP update that matches an accept policy go to the policy prompt for example box ip bgp accept policy_1 and enter modify The modification prompt appears for the policy For example accept pol_1 bgp modify modify
246. ure local preference calculation go to the BGP prompt for example box ip bgp and enter local pref calculation lt state gt state is one of the values shown in Table 3 5 308628 15 0 Rev 00 3 27 Configuring IP Exterior Gateway Protocols BGP and EGP Table 3 5 Local Preference Calculation Method State Meaning enabled default BGP uses the decision rules in the first column of Table 3 4 for local preference calculation and best route selection disabled BGP does not perform local preference calculation Instead it assigns a value of 100 to the route and uses a modified formula for best route selection For example the following command disables BayRS BGP local preference calculation and route selection bgp local pref calculation disabled bgp Using Site Manager To disable or reenable local preference calculation complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window The Protocols menu opens choose Protocols 2 Choose IP The IP menu opens 3 Choose BGP The BGP menu opens 4 Choose BGP Global The Edit BGP Global Parameters window opens 5 Set the Local Pref Calculation parameter Click on Help or see the parameter description on page A 9 6 Click on OK You return to the Configuration Manager window 3 28 308628 15 0 Rev 00 Configuring Global BGP Parameters Conf
247. ute flap damping see Configuring EBGP Route Flap Damping on page 3 31 route damping template default or a unique template name up to 20 characters Configures BGP to use the default route flap damping template or the template that you specify state enabled default disabled Enables and disables the policy that you created 308628 15 0 Rev 00 Configuring BGP Accept and Announce Policies For example the following command sequence causes BGP to accept routes that match policy_2 and assigns a BGP 4 preference of 10 to routes that match this policy accept policy_2 bgp action accept accept policy_2 bgp bgp 4 preference 10 accept policy_2 bgp Using Site Manager To create a BGP accept policy complete the following steps Site Manager Procedure You do this System responds 1 In the Configuration Manager window choose Protocols The Protocols menu opens Choose IP The IP menu opens Choose Policy Filters Choose BGP 4 The Policy Filters menu opens The BGP 4 Policies menu opens ay oO N Choose Accept Policies The BGP4 Accept Policy Filters window opens Click on Add The BGP4 Accept IP Policy Filter Configuration window opens Set the following parameters Name Action Route Preference Rule Precedence Bgp4 Preference AS Weight Class Click on Help or see the parameter descriptions begin
248. value that you specify as the cutoff threshold BGP suppresses the route e Reuse threshold If the penalty value falls below the value that you specify as the reuse threshold BGP unsuppresses the route e Reachable decay If the route is still reachable after the period of time that you specify BGP reduces the penalty value by half BGP uses a half life decay algorithm to decrement the penalty value e Unreachable decay If the route is still unreachable after the period of time that you specify BGP reduces the penalty value by half BGP uses a half life decay algorithm to decrement the penalty value 308628 15 0 Rev 00 3 31 Configuring IP Exterior Gateway Protocols BGP and EGP e Maximum holddown time If the route remains suppressed after the number of minutes that you specify BGP unsuppresses it even if the penalty value exceeds the threshold This action does not change the penalty value e Memory limit If the status of the route remains unchanged either reachable or unreachable after the number of minutes that you specify BGP unsuppresses the route if it is suppressed and resets the penalty value and flap count to 0 Note A route that has been suppressed may not be immediately available for use as soon as the penalty value crosses the configured threshold You can also use the BCC or Site Manager to create a route flap damping template and a BGP accept policy for route flap damping Using the BCC T
249. wing TCP options kind 19 length 18 4 24 308628 15 0 Rev 00 Configuring BGP Peers Verifying MD5 Signatures on Received BGP TCP Packets Upon receiving a packet TCP performs three tests e Ifa packet passes a test it proceeds to the next test When a packet has passed all three tests TCP accepts the packet and sends it to BGP e Ifa packet fails a test TCP logs an event increments the count of TCP connection errors wfT cpConnMd5Errors and discards the packet The TCP connection remains open Table 4 1 lists the tests and the event message that TCP logs if a test fails Table 4 1 MD5 Signature Verification Rules on BGP TCP Packets Condition Tested Action on Success Failure Event Message Is the connection configured for MD5 Verify that the packet contains TCP MD5 No Signature authentication a kind 19 option Is MD5 authentication enabled for this TCP computes the expected TCP MD5 Authentication TCP connection MD5 signature Disabled Does the computed MD5 signature TCP sends the packet to BGP TCP MD5 Invalid Signature match the received MD5 signature For information about signatures see Generating MD5 Signatures on Transmitted BGP TCP Packets on page 4 24 Configuring BGP 4 Authentication You can use the BCC or Site Manager to configure BGP 4 authentication Note You must use the Technician Interface secure shell to enter the message encryption key node pro
250. wise the keepalive timer is set to the smaller of this configured value and one third of the holdtime Either accept the current keepalive value or set this parameter to some value greater than 0 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 15 308628 15 0 Rev 00 Configuring IP Exterior Gateway Protocols BGP and EGP Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Parameter Path Default Options Function Instructions MIB Object ID Min AS Origination Interval Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 15 seconds A value greater than 0 Determines the minimum amount of time that must elapse between successive advertisements of update messages that report changes within the advertising BGP speaker s own autonomous system Enter a value greater than 0 seconds 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 30 Local AS to Advertise to Peer Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 0 0 to 65535 Specifies the AS number that is sent in an open message to this peer Enter an AS number To specify the AS number that you set with the BGP Local AS parameter use the default 1 3 6 1 4 1 18 3 5 3 2 5 1 2 1 31 Peer Max Update Size Configuration Manager gt Protocols gt IP gt BGP gt Peers gt BGP Peers 800 bytes 64 to 4096 Specifies th
251. works announce A 52 Next Hop announce A 78 Origin announce A 72 A 76 Originating AS accept A 37 A 41 Outbound Peer AS announce A 74 Outbound Peer AS List announce A 70 Outbound Peers announce A 71 A 75 Peer Address accept A 37 A 41 Peer AS accept A 37 A 40 Peer List accept A 34 Precedence announce A 54 Received BGP Next Hop announce A 67 Received EGP Gateway announce A 64 308628 15 0 Rev 00 Received on RIP Interface announce A 58 Received OSPF Tag announce A 61 Received OSPF Type announce A 60 Replace As Path announce A 77 Route Flap Dampening accept A 45 Route Flap Dampening Template accept A 46 Route Origin accept A 38 A 41 Route Preference accept A 33 Rule Precedence accept A 34 Specific Inter AS Metric announce A 72 Weight Class accept A 38 poll mode for EGP neighbors 8 12 Poll Mode parameter 8 12 A 27 Poll Timer parameter 8 13 A 28 precedence accept policies 5 2 announce policies 5 13 preference accept policies 5 2 product support xxi publications hard copy xx related xx R redundant connections BGP enabling and disabling 3 12 Remote Autonomous System IP Address parameter EGP 8 8 EGP neighbor 2 6 A 25 Remote Peer IP Address EGP neighbor 2 6 A 26 RIP interaction with BGP configuring 3 9 route balancing described 1 8 EBGP 7 5 IBGP 7 1 route echo switch BGP enabling and disabling 4 19 rou

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