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Cisco Systems BC-281 User's Manual

1. SNASw DLSw Data link users CLSI Token 1 eee i l VDLC l Ethernet Data link controls Ring I i PE dep pect ae Ss Eh 51909 The higher layer protocols make no distinction between the VDLC and any other data link control but they do identify the VDLC as a destination In the example shown in Figure 129 SNASw has two ports a physical port for Token Ring and a virtual port for the VDLC When you define the SNASw VDLC port you can specify the MAC address assigned to it Data transport from SNASw to DLSw by way of the VDLC is directed to the VDLC MAC address The type of higher layer protocol you use determines how the VDLC MAC address is assigned DLSw Configuration Task List DLSw supports local or remote media conversion between LANs and SDLC or QLLC To configure DLSw complete the tasks in the following sections Defining a DLSw Local Peer for the Router page 288 Defining a DLSw Remote Peer page 289 Mapping DLSw to a Local Data Link Control page 292 Configuring Advanced Features page 295 Configuring DLSw Timers page 310 See the DLSw Configuration Examples section on page 312 for examples Defining a DLSw Local Peer for the Router Command Defining a DLSw local peer for a router enables DLSw Specify all local DLSw parameters as part of the local peer definition To define a local peer use the following command in global configuration mode Purpose
2. Router config dlsw local peer peer id group group border cluster cost cost 1f size keepalive ip address cluster id seconds init pacing window size max pacing window size biu segment promiscuous Defines the DLSw local peer The following is a sample dlsw local peer statement disw local peer peer id 10 2 34 3 Cisco 10S Bridging and IBM Networking Configuration Guide BC 288 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Task List Ti Defining a DLSw Remote Peer Defining a remote peer in DLSw is optional however usually at least one side of a peer connection has a dlsw remote peer statement If you omit the dlsw remote peer command from a DLSw peer configuration then you must configure the promiscuous keyword on the dlsw local peer statement Promiscuous routers will accept any peer connection requests from other routers that are not preconfigured To define a remote peer use the dlsw remote peer command in global configuration mode One of the options in the remote peer statement is to specify an encapsulation type Configure one of the following types of encapsulations with the dlsw remote peer statement TCP Encapsulation page 289 TCP IP with RIF Passthrough Encapsulation page 290 FST Encapsulation page 290 Direct Encapsulation page 291 DLSw Lite Encapsulation page 291 Which encapsulation type you choose depends on
3. Router config dlsw remote peer tcp circuit weight value Adjusts the circuit weight on the remote peer To adjust the circuit weight for a remote peer with DLSw Lite encapsulation use the following command in global configuration mode Command Purpose Router config dlsw remote peer frame relay interface serial number dlci number circuit weight value Adjusts the circuit weight on the remote peer The circuit weight of a remote peer controls the number of circuits that peer can take If multiple equally low cost peers can reach a remote source the circuits to that remote source are distributed among the remote peers based on the ratio of their configured circuit weights The peer with the highest circuit weight takes more circuits Because a DLSw peer selects its new circuit paths from within its reachability cache the user must configure the dlsw timer explorer wait time command with enough time to allow for all the explorer responses to be received If the new DLSw Enhanced Load Balancing Feature is enabled a message is displayed on the console to alert the user if the timer is not set To configure the amount of time needed for all the explorer responses to be received use the following command in global configuration mode Command Purpose Router config dlsw timer explorer wait time Sets the time to wait for all stations to respond to explorers See the DLSw Design a
4. 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Task List LLC1 Circuits Support for LLC1 circuits more efficiently transports LLC1 UI traffic across a DLSw cloud With LLC1 circuit support the LLC1 unnumbered information frames UI are no longer subject to input queueing and are guaranteed to traverse the same path for the duration of the flow This feature improves transportation of LLC1 UI traffic because there is no longer the chance of having a specifically routed LLC1 UI frame broadcast to all remote peers The circuit establishment process has not changed except that the circuit is established as soon as the specifically routed LLC1 UI frame is received and the DLSw knows of reachability for the destination MAC address Furthermore the connection remains in the CIRCUIT_ESTABLISHED state rather than proceeding to the CONNECT state until there is no UI frame flow for a MAC SAP pair for 10 minutes This feature is enabled by default Dynamic Peers In TCP encapsulation the dynamic option and its suboptions no Ilc and inactivity allow you to specify and control the activation of dynamic peers which are configured peers that are activated only when required Dynamic peer connections are established only when there is DLSw data to send The dynamic peer connections are taken down when the last LLC2 connection using them terminates and the
5. Configuring Data Link Switching Plus E DLSw Configuration Examples Router A source bridge ring group 1111 dlsw local peer peer id 10 2 2 2 dlsw remote peer 0 tcp 10 1 1 1 interface loopback 0 ip address 10 2 2 2 255 255 255 0 interface TokenRing 0 no ip address ring speed 16 source bridge 2 1111 source bridge spanning Router B disw local peer peer id 10 1 1 1 dlsw remote peer 0 tcp 10 2 2 2 interface loopback 0 ip address 10 1 1 1 255 255 255 0 interface serial 0 mtu 4096 no ip address encapsulation sdlc no keepalive nzri encoding clockrate 9600 sdlc vmac 4000 3745 0000 sdlc N1 48016 sdlc address 04 echo sdlc partner 4000 1111 0020 04 sdlc dlsw 4 DLSw Translation Betw een Ethernet and Token Ring Configuration Example DLSw also supports Ethernet media The configuration is similar to other DLSw configurations except for configuring for a specific media The following example shows Ethernet media see Figure 135 Figure 135 DLSw Translation Between Ethemet and Token Ring Router A Router B m Z Z oqe z ag 1 2 i J N J 128 207 1 145 128 207 111 1 Token 83584 AS 400 j Router A hostname Router A l dlsw local peer peer id 128 207 111 1 dlsw remote peer 0 tcp 128 207 1 145 Cisco IOS Bridging and IBM Netw orking Configuration Guide T BC 320 iE A _Configuring Data Link Switching Plus DLSw Configuration Examples W dlsw bridge group 5
6. Both Router A and Router B execute the full LLC2 protocol as part of local acknowledgment for LLC2 Figure 128 LLC2 Session with Local Acknowledgment lt TCP session gt lt LLC session gt 1107a lt SNA session gt With local acknowledgment for LLC2 enabled in both routers Router A acknowledges frames received from the 37x5 The 37x5 still operates as if the acknowledgments it receives are from the 3x74 Router A looks like the 3x74 to the 37x5 Similarly Router B acknowledges frames received from the 3x74 The 3x74 operates as if the acknowledgments it receives are from the 37x5 Router B looks like the 3x74 to 37x5 Because the frames do not have to travel the WAN backbone networks to be acknowledged but are locally acknowledged by routers the end machines do not time out resulting in no loss of sessions 78 11737 02 Cisco 10S Bridging and IBM Networking Configuration Guide BC 285 Configuring Data Link Switching Plus E Technology Overview Enabling local acknowledgment for LLC2 has the following advantages Local acknowledgment for LLC2 solves the T1 timer problem without having to change any configuration on the end nodes The end nodes are unaware that the sessions are locally acknowledged In networks consisting of hundreds or even thousands of machines this is a definite advantage All the frames acknowledged by the Cisco IOS software appear to the en
7. destination subsequent explorers for that MAC address or NetBIOS name are merely stored When the explorer response is received at the originating DLSw all explorers receive an immediate local response This eliminates the start of day explorer storm that many networks experience Configure the disw timer command to enable explorer firewalls See the Configuring DLSw Timers section on page 310 for details of the command To enable explorer firewalls use the following command in global configuration mode Purpose Router config dlsw timer Tunes an existing configuration parameter icannotreach block time netbios cache timeout netbios explorer timeout netbios group cache netbios retry interval netbios verify interval sna cache timeout explorer delay time sna explorer timeout explorer wait time sna group cache sna retry interval sna verify interval time Command NetBIOS Dial on Demand Routing This feature allows you to transport NetBIOS in a dial on demand routing DDR environment by filtering NetBIOS Session Alive packets from the WAN NetBIOS periodically sends Session Alive packets as LLC2 I frames These packets do not require a response and are superfluous to the function of proper data flow Furthermore these packets keep dial on demand interfaces up and this up time causes unwanted per packet charges in DDR networks By filtering these NetBIOS Session Alive packets you reduce traffic
8. reachability information Router dlsw disable Disables and re enable DLSw without altering the configuration Router show dlsw statistics border peers Displays the number of frames that have been processed in the local remote and group caches Router clear dlsw circuit Closes all the DLSw circuits Also used to reset to zero the number of frames that have been processed in the local remote and group cache 1 Issuing the clear dlsw circuits command will cause the loss of any associated LLC2 sessions Cisco IOS Bridging and IBM Networking Configuration Guide 78 11737 02 g BC311 Configuring Data Link Switching Plus E DLSw Configuration Examples See the DLSw Design and Implementation Guide Using Show and Debug Commands chapter and the Cisco IOS Bridging and IBM Networking Command Reference Volume 1 of 2 for details of the commands DLSw Configuration Examples The following sections provide DLSw configuration examples DLSw Using TCP Encapsulation and LLC2 Local Acknowledgment Basic Configuration Example page 312 DLSw Using TCP Encapsulation with Local Acknowledgment Peer Group Configuration Example 1 page 314 DLSw Using TCP Encapsulation with Local Acknowledgment Peer Group Configuration Example 2 page 316 DLSw with SDLC Multidrop Support Configuration Examples page 318 DLSw with LLC2 to SDLC Conversion Between PU 4 to PU 4 Communication Example page 319 D
9. time period specified in the no llc option expires You can also use the inactivity option to take down dynamic peers when the circuits using them are inactive for a specified number of minutes Note Command Because the inactivity option may cause active LLC2 sessions to be terminated you should not use this option unless you want active LLC2 sessions to be terminated To configure a dynamic peer use the following command in global configuration mode Purpose Router config dlsw remote peer list number tcp Configures a dynamic peer ip address backup frame relay interface serial number dlci number interface name access list number keepalive seconds timeout seconds bytes list name circuit weight weight cluster cluster id cost cost dest mac mac address dmac host list name inactivity dynamic lsap output list list no llc minutes passive priority rif passthru virtual ring number tcp queue max size peer ip address bytes netbios out output list host netbios out 1f size linger minutes The following command specifies a dynamic peer with TCP encapsulation dlsw remote peer 0 tcp 10 23 4 5 dynamic Promiscuous Peer Defaults If you do not configure a dlsw remote peer statement on the DLSw router then you must specify the promiscuous keyword on the dlsw local peer statement The promiscuous keyword enables the router to accept peer connection requ
10. 150 2 3 255 255 255 0 dlsw transparent redundancy enable 9999 9999 9999 Router D disw local peer peer id 10 2 17 1 promiscuous DLSw with Ethernet Redundancy Enabled for Switch Support Configuration Example Figure 145 is a sample configuration of the DLSw Ethernet Redundancy feature in a switched environment The ethernet switch sees the device with MAC address 4000 0010 0001 one port at a time because Router A and Router B have mapped different MAC addresses to it This configuration is known as MAC address mapping Router A is configured so that MAC address 4000 0001 0000 maps to the actual device with MAC address 4000 0010 0001 Router B is configured so that MAC address 4000 0201 0001 maps to the actual device with MAC address 4000 0010 0001 Router A and B backup one another Router A is configured as the master with a default priority of 100 Master Router A waits 1 5 seconds after it receives the first IWANTIT primitive before assigning the new SNA circuit to one of its ethernet redundancy peers because of the dlsw transparent timers sna 7500 command Figure 145 DLSw with Ethemet Redundancy in a Switched Environment Workstation Z Ly Pzd Workstation X Router A y7 4000 0010 0001 Z i Z D Router B Ethernet switch 17956 Cisco IOS Bridging and IBM Netw orking Configuration Guide T BC 332 U A _Configuring Data Link Switching Plus DLSw Configuration Examples Router A dlsw local pe
11. Router B Router C AD s0 FT DE 2 7 d t0 eg t3 1 l p 2 BI y 128 207 152 5 128 207 150 8 128 207 169 3 NetBIOS border border NetBIOS server requester __ Group 70 Group 69 3242 Router A hostname Router A source bridge ring group 31 dlsw local peer peer id 128 207 152 5 group 70 promiscuous dlsw remote peer 0 tcp 128 207 150 8 interface loopback 0 ip address 128 207 152 5 255 255 255 0 1 interface serial 0 ip unnumbered tokenring clockrate 56000 interface tokenring 0 ip address 128 207 152 5 255 255 255 0 ring speed 16 source bridge 200 13 31 source bridge spanning I router igrp 777 network 128 207 0 0 Router B hostname Router B source bridge ring group 31 disw local peer peer id 128 207 150 8 group 70 border promiscuous dlsw remote peer 0 tcp 128 207 169 3 interface loopback 0 ip address 128 207 150 8 255 255 255 0 Cisco 10S Bridging and IBM Networking Configuration Guide T BC 314 i A _Configuring Data Link Switching Plus DLSw Configuration Examples W I interface serial 0 ip unnumbered tokenring 0 bandwidth 56 interface tokenring 0 ip address 128 207 150 8 255 255 255 0 ring speed 16 source bridge 3 14 31 source bridge spanning 1 router igrp 777 network 128 207 0 0 Router C hostname Router C source bridge ring group 69 dlsw local peer peer id 128 207 169 3 group 69 border promiscuous dlsw remote peer 0 tcp 128 207 150 8 interface loopb
12. configuring the connection in advance It also allows any to any switching in large internetworks where persistent TCP connections would not be possible Bridging and IBM Networking Configuration Guide Cisco IOS BC 298 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Task List W To configure peer on demand defaults use the following command in global configuration mode Command Purpose Router config dlsw peer on demand defaults fst bytes netbios out bytes list name cost cost dest mac destination mac address dmac output list access list number host netbios out host list name inactivity minutes keepalive seconds lf size lsap output list list port list port list number priority tcp queue max Configures peer on demand defaults To define the maximum entries maintained in a border peer s group cache use the following command in global configuration mode Command Purpose Router config dlsw group cache max entries number Defines the maximum entries in a group cache To remove all entries from the DLSw reachability cache use the following command in privileged EXEC mode Command Purpose Router clear dlsw reachability Removes all entries from the DLSw reachability cache To reset to zero the number of frames that have been processed in the local remote and group caches use the following command in privi
13. frame relay map dlsw 30 Router B source bridge ring group 100 dlsw local peer 10 2 23 2 disw remote peer 0 frame relay interface serial 0 30 passthru interface loopback 0 ip address 10 2 23 2 255 255 255 0 interface tokenring 0 ring speed 16 source bridge spanning 2 1 100 Cisco 10S Bridging and IBM Networking Configuration Guide T BC 324 i A _Configuring Data Link Switching Plus DLSw Configuration Examples W interface serial 0 mtu 3000 no ip address encapsulation frame relay frame relay lmi type ansi frame relay map dlsw 30 DLSw over QLLC Configuration Examples The following three examples describe QLLC support for DLSw Example 1 In this configuration DLSw is used to allow remote devices to connect to a DLSw network over an X 25 public packet switched network In this example all QLLC traffic is addressed to destination address 4000 1161 1234 which is the MAC address of the FEP The remote X 25 attached IBM 3174 cluster controller is given a virtual MAC address of 1000 0000 0001 This virtual MAC address is mapped to the X 121 address of the 3174 31104150101 in the X 25 attached router interface serial 0 encapsulation x25 x25 address 3110212011 x25 map qllc 1000 0000 0001 31104150101 qllc dlsw partner 4000 1611 1234 Example 2 In this configuration a single IBM 3174 cluster controller needs to communicate with both an AS 400 and a FEP The FEP is associated with subaddress 1
14. on the WAN and you reduce some costs that are associated with dial on demand routing To enable NetBIOS DDR use the following command in global configuration mode Purpose Router config dlsw netbios keepalive filter Enables NetBIOS DDR The following command enables NetBIOS DDR dlsw netbios keepalive filter Cisco 10S Bridging and IBM Networking Configuration Guide BC 300 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Task List W SNA Dial on Demand Routing This feature allows you to run DLSw over a switched line and have the Cisco IOS software take the switched line down dynamically when it is not in use Utilizing this feature gives the IP Routing table more time to converge when a network problem hinders a remote peer connection In small networks with good IP convergence time and ISDN lines that start quickly it is not as necessary to use the keepalive option To use this feature you must set the keepalive value to zero and you may need to use a lower value for the timeout option than the default which is 90 seconds To configure SNA DDR use the following command in global configuration mode Command Purpose Router config dlsw remote peer list number tcp ip address backup peer ip address frame relay interface serial number dlci number interface name bytes netbios out bytes list name circuit weight weight cluster cluster id cost cost dest mac m
15. the local Ethernet bridge group interface to remote peers You can create a bridge group list and apply the list to remote peer definitions Traffic received from a remote peer is only forwarded to the bridge group specified in the bridge group list Traffic received from a local interface is only forwarded to peers if the input bridge group number appears in the bridge group list applied to the remote peer definition The definition of a bridge group list is optional Because each remote peer has a single list number associated with it if you want traffic to go to a bridge group and to either a ring list or port list you should specify the same list number in each definition To define a bridge group list use the following command in global configuration mode Purpose Router config dlsw bgroup list list number bgroups number Defines a ring list Cisco IOS Bridging and IBM Networking Configuration Guide BC 308 78 11737 02 _Configuring Data Link Switching Plus Command DLSw Configuration Task List I Static Paths Static path definitions allow a router to setup circuits without sending explorers The path specifies the peer to use to access a MAC address or NetBIOS name To configure static paths to minimize explorer traffic originating in this peer use one of the following commands in global configuration mode as needed Purpose Router config dlsw mac addr mac addr ring Configures the locatio
16. time delays encapsulate the source route bridged traffic inside IP datagrams passed over a TCP connection between two routers with local acknowledgment enabled Logical Link Control type 2 LLC2 is an ISO standard data link level protocol used in Token Ring networks LLC2 was designed to provide reliable sending of data across LAN media and to cause minimal or at least predictable time delays However DLSw and WAN backbones created LANs that are separated by wide geographic distances spanning countries and continents As a result LANs have time delays that are longer than LLC2 allows for bidirectional communication between hosts Local acknowledgment addresses the problem of unpredictable time delays multiple sendings and loss of user sessions In a typical LLC2 session when one host sends a frame to another host the sending host expects the receiving host to respond positively or negatively in a predefined period of time commonly called the T time If the sending host does not receive an acknowledgment of the frame it sent within the T1 time it retries a few times normally 8 to 10 If there is still no response the sending host drops the session Figure 127 illustrates an LLC2 session in which a 37x5 on a LAN segment communicates with a 3x74 on a different LAN segment separated via a wide area backbone network Frames are transported between Router A and Router B by means of DLSw However the LLC2 session between the 37x5 and the 3x7
17. to Switch Protocol SSP connections between two DLSw peers when no circuits are available Ensures that each broadcast results in only a single explorer over every link DLSw Version 2 is for customers who run a multicast IP network and do not need the advantages of border peering Cisco 10S Bridging and IBM Networking Configuration Guide BC 282 78 11737 02 _Configuring Data Link Switching Plus UDP Unicast Technology Overview Mil DLSw Version 2 uses UDP unicast in response to an IP multicast When address resolution packets CANUREACH_EX NETBIOS_NQ_ex NETBIOS_ANQ and DATAFRAME are sent to multiple destinations IP multicast service DLSw Version 2 sends the response frames ICANREACH_ex and NAME_RECOGNIZED_ex via UDP unicast UDP unicast uses UDP source port 0 However some firewall products treat packets that use UDP source port 0 as security violations discarding the packets and preventing DLSw connections To avoid this situation use one of the following procedures Configure the firewall to allow UDP packets to use UDP source port 0 Use the dlsw udp disable command to disable UDP unicast and send address resolution packets in the existing TCP session Enhanced Peer on Demand Routing Feature DLSw Version 2 establishes TCP connections only when necessary and the TCP connections are brought down when there are no circuits to a DLSw peer for a specified amount of time This method known as peer on deman
18. 1 interface loopback 0 ip address 128 207 111 1 255 255 255 0 interface Ethernet 0 no ip address bridge group 5 I bridge 5 protocol ieee Router B hostname Router B l source bridge transparent 500 1000 1 5 dlsw local peer peer id 128 207 1 145 dlsw remote peer 0 tcp 128 207 111 1 dlsw bridge group 5 I interface loopback 0 ip address 128 207 1 145 255 255 255 0 interface ethernet 1 2 no ip address bridge group 5 I interface tokenring 2 0 no ip address ring speed 16 source bridge 7 1 500 source bridge spanning I bridge 5 protocol ieee Because DLSw does not do local translation between different LAN types Router B must be configured for SR TLB by issuing the source bridge transparent command Also note that the bridge groups are configured on the ethernet interfaces DLSw Translation Betw een FDDI and Token Ring Configuration Example DLSw also supports FDDI media The configuration is similar to other DLSw configurations except for configuring for a specific media type The following example shows FDDI media see Figure 136 Figure 136 DLSw Translation Between FDDI and Token Ring Om n me Ring Router A Router B H6565 In the following configuration an FDDI ring on Router A is connected to a Token Ring on Router B across a DLSw link Router A source bridge ring group 10 dlsw local peer peer id 132 11 11 2 dlsw remote peer 0 tcp 132 11 11 3 interface loopback 0 ip address 132
19. 11 11 2 255 255 255 0 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Examples interface fddi 0 no ip address source bridge 26 1 10 source bridge spanning Router B source bridge ring group 10 dlsw local peer peer id 132 11 11 3 dlsw remote peer 0 tcp 132 11 11 2 interface loopback 0 ip address 132 11 11 3 255 255 255 0 interface tokenring 0 no ip address source bridge 25 1 10 source bridge spanning DLSw Translation Between SDLC and Token Ring Media Example DLSw provides media conversion between local or remote LANs and SDLC For additional information about configuring SDLC parameters refer to the chapter Configuring LLC2 and SDLC Parameters Figure 137 illustrates DLSw with SDLC encapsulation For this example 4000 1020 1000 is the MAC address of the FEP host PU 4 0 The MAC address of the AS 400 host is 1000 5aed 1f53 which is defined as Node Type 2 1 Router B serves as the primary station for the remote secondary station 01 Router B can serve as either primary station or secondary station to remote station D2 Figure 137 DLSw Translation Between SDLC and Token Ring Media 1000 5aed 1F53 FEP 4000 1020 1000 Router B e 8 oe Token i a z 5l y Ring 100 Router A S2 S1 PU type 2 1 PU type 2 0 a sdic address sdic address wo 01 Router A hostname Router A source bridge ring group
20. 2000 disw local peer peer id 150 150 10 2 dlsw remote peer 0 tcp 150 150 10 1 Cisco 10S Bridging and IBM Networking Configuration Guide ca 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Examples W 1 interface loopback 0 ip address 150 150 10 2 255 255 255 0 interface serial 8 ip address 150 150 11 2 255 255 255 192 clockrate 56000 i interface tokenring 0 no ip address ring speed 16 source bridge 500 1 2000 source bridge spanning 1 router eigrp 202 network 150 150 0 0 Router B hostname Router B 1 source bridge ring group 2000 dlsw local peer peer id 150 150 10 1 dlsw remote peer 0 tcp 150 150 10 2 interface loopback 0 ip address 150 150 10 1 255 255 255 0 interface serial 0 ip address 150 150 11 1 255 255 255 192 interface serial 1 description PU2 with SDLC station role set to secondary no ip address encapsulation sdlc no keepalive clockrate 9600 sdlc role primary sdlic vmac 4000 9999 0100 sdlc address 01 sdlc xid 01 05d20006 sdlc partner 4000 1020 1000 01 sdic dlsw 1 l interface serial 2 description Node Type 2 1 with SDLC station role set to negotiable or primary encapsulation sdlc sdlc role prim xid poll sdlc vmac 1234 3174 0000 sdlc address d2 sdlc partner 1000 5aed 1f53 d2 sdlc dlsw d2 I interface tokenring 0 no ip address ring speed 16 source bridge 100 1 2000 source bridge spanning 1 interface tokenring 1 no ip addre
21. 4 is still end to end that is every frame generated by the 37x5 traverses the backbone network to the 3x74 and the 3x74 on receipt of the frame acknowledges it Cisco 10S Bridging and IBM Networking Configuration Guide BC 284 78 11737 02 _Configuring Data Link Switching Plus Technology Overview W Figure 127 LLC2 Session without Local Acknowledgment y Router A Z Toxen ae Ring 37x5 lt LLC2 session gt P 1 8 lt SNA session gt 5 On backbone networks consisting of slow serial links the T1 timer on end hosts could expire before the frames reach the remote hosts causing the end host to resend Resending results in duplicate frames reaching the remote host at the same time as the first frame reaches the remote host Such frame duplication breaks the LLC2 protocol resulting in the loss of sessions between the two IBM machines One way to solve this time delay is to increase the timeout value on the end nodes to account for the maximum transit time between the two end machines However in networks consisting of hundreds or even thousands of nodes every machine would need to be reconfigured with new values With local acknowledgment for LLC2 enabled the LLC2 session between the two end nodes would not be not end to end but instead would terminate at two local routers Figure 128 shows the LLC2 session with the 37x5 ending at Router A and the LLC2 session with the 3x74 ending at Router B
22. 50101 and the AS 400 is associated with subaddress 151102 If an X 25 call comes in for 33204150101 the call is mapped to the FEP and forwarded to MAC address 4000 1161 1234 The IBM 3174 appears to the FEP as a Token Ring attached resource with MAC address 1000 0000 0001 The IBM 3174 uses a source SAP of 04 when communicating with the FEP and a source SAP of 08 when communicating with the AS 400 interface serial 0 encapsulation x25 x25 address 31102 x25 map qllc 1000 0000 0001 33204 qllc dlsw subaddress 150101 partner 4000 1161 1234 qllc dlsw subaddress 150102 partner 4000 2034 5678 sap 04 08 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide pg Configuring Data Link Switching Plus E DLSw Configuration Examples Example 3 In this example two different X 25 resources want to communicate over X 25 to the same FEP In the router attached to the X 25 network every X 25 connection request for X 121 address 31102150101 is directed to DLSw The first SVC to be established will be mapped to virtual MAC address 1000 0000 0001 The second SVC to be established will be mapped to virtual MAC address 1000 0000 0002 interface serial 0 encapsulation x25 x25 address 31102 x25 map qlic 33204 x25 map qlic 35765 qlic dlsw subaddress 150101 vmacaddr 1000 0000 0001 2 partner 4000 1611 1234 DLSw with RIF Passthrough Configuration Example Figure 139 is a sample configuration for DLSw using the RIF Pa
23. 6 1 2000 source bridge spanning I interface tokenring 0 1 Cisco IOS Bridging and IBM Networking Configuration Guide 78 11737 02 a Configuring Data Link Switching Plus E DLSw Configuration Examples no ip address ring speed 16 source bridge 92 1 2000 source bridge spanning interface tokenring 0 2 no ip address ring speed 16 source bridge 93 1 2000 source bridge spanning router eigrp 202 network 150 150 0 0 Router E hostname Router E source bridge ring group 2000 dlsw local peer peer id 150 150 97 1 group 1 promiscuous dlsw remote peer 0 tcp 150 150 96 1 interface loopback 0 ip address 150 150 97 1 255 255 255 192 interface tokenring 0 no ip address ring speed 16 source bridge 97 1 2000 source bridge spanning router eigrp 202 network 150 150 0 0 DLSw with SDLC Multidrop Support Configuration Examples In the following example all devices are type PU 2 0 interface serial 2 mtu 4400 no ip address encapsulation sdlc no keepalive clockrate 19200 sdlc sdlc sdlc sdlc sdlc sdlc sdlc sdlc sdlc role primary vmac 4000 1234 5600 address Cl xid C1 O5DCCCC1 partner 4001 3745 1088 C1 address C2 xid C2 05DCCCC2 partner 4001 3745 1088 C2 dlsw C1 C2 The following example shows mixed PU 2 0 device using address C1 and PU 2 1 device using address C2 devices interface serial 2 mtu 4400 no ip address encapsulation sdlc no keepalive
24. Cisco 10S Bridging and IBM Networking Configuration Guide BC 318 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Examples W clockrate 19200 sdlc role primary sdlc vmac 4000 1234 5600 sdlc address C1 sdlc xid Cl 05DCCCC1 sdlc partner 4001 3745 1088 C1 sdlc address C2 xid poll sdlc partner 4001 3745 1088 C2 sdlc dlsw C1 C2 In the following example all devices are type PU 2 1 Method 1 interface serial 2 mtu 4400 no ip address encapsulation sdlc no keepalive clockrate 19200 sdlc role primary sdlc vmac 4000 1234 5600 sdlc address C1 xid poll sdlc partner 4001 3745 1088 C1 sdlc address C2 xid poll sdlc partner 4001 3745 1088 C2 sdlc dlsw C1 C2 In the following example all devices are type PU 2 1 Method 2 interface serial 2 mtu 4400 no ip address encapsulation sdlc no keepalive clockrate 19200 sdlc role prim xid poll sdlc vmac 4000 1234 5600 sdlc address Cl sdlc partner 4001 3745 1088 C1 sdlc address C2 sdlc partner 4001 3745 1088 C2 sdlc dlsw C1 C2 DLSw with LLC2 to SDLC Conversion Between PU 4 to PU 4 Communication Example The following example is a sample configuration for LLC2 to SDLC conversion for PU 4 to PU 4 communication as shown in Figure 134 Figure 134 LLC2 to SDLC Conversion for PU 4 to PU 4 Communication ws ws Tok 2 gt eae z M M y Frame Relay i r S6283 Cisco IOS Bridging and IBM Networking Configuration Guide ere E BC 319
25. Command Reference Volume 1 of 2 for command details To verify that DLSw is configured on the router use the following command in privileged EXEC mode Purpose Router show dlsw capabilities local Displays the DLSw configuration of a specific peer version number release number init pacing window unsupported saps num of tcp sessions loop prevent support icanreach mac exclusive icanreach netbios excl reachable mac addresses reachable netbios names cisco version number peer group number border peer capable peer cost biu segment configured UDP Unicast support local ack configured priority configured no no no none none si 20 no 73 no yes yes no Cisco Internetwork Operating System Software IOS GS Software GS7 K M Experimental Version 11 1 10956 sbales 139 Copyright c 1986 1996 by cisco Systems Inc Compiled Thu 30 May 96 09 12 by sbales8 The following sample shows that DLSw is configured on router milan milan show dlsw capabilities local DLSw Capabilities for peer 1 1 1 6 2065 vendor id OUI 00C sid 20 20 none cisco If only a command prompt appears then DLSw is not configured for the router Cisco IOS Bridging and IBM Networking Configuration Guide PBC 310 E 78 11737 02 _Configuring Data Link Switching Plus Monitoring and Maintaining the DLSw Network W Alternately to verify that DLSw is configured issue the following command in privileg
26. Configuring Data Link Switching Plus This chapter describes how to configure data link switching plus DLSw Cisco s implementation of the DLSw standard for Systems Network Architecture SNA and NetBIOS devices Refer to the DLSw Design and Implementation Guide for more complex configuration instructions For a complete description of the DLSw commands mentioned in this chapter refer to the DLSw Commands chapter of the Cisco IOS Bridging and IBM Networking Command Reference Volume of 2 To locate documentation of other commands that appear in this chapter use the command reference master index or search online This chapter contains the following sections Technology Overview page 281 DLSw Configuration Task List page 288 Verifying DLSw page 310 Monitoring and Maintaining the DLSw Network page 311 DLSw Configuration Examples page 312 To identify the hardware platform or software image information associated with a feature use the Feature Navigator on Cisco com to search for information about the feature or refer to the software release notes for a specific release For more information see the Identifying Platform Support for Cisco IOS Software Features section on page lv in the Using Cisco IOS Software chapter Technology Overview DLSw is a method of transporting SNA and NetBIOS It complies with the DLSw standard documented in RFC 1795 and the DLSw Version 2 standard DLSw is an alternati
27. For dynamic peers in TCP encapsulation these filters also control the activation of the dynamic peer For example you can specify at a branch office that a remote peer is activated only when there is an explorer frame destined for the Media Access Control MAC address of an FEP The dest mac option permits the connection to be established only when there is an explorer frame destined for the specified MAC address The dmac output list option permits the connection to be established only when the explorer frame passes the specified access list To permit access to a single MAC address use the dest mac option because it is a configuration shortcut compared to the dmac output list option 78 11737 02 Cisco 10S Bridging and IBM Networking Configuration Guide BC 309 Configuring Data Link Switching Plus Verifying DLSw Configuring DLSw Timers Command To configure DLSw timers use the following command in global configuration mode Purpose Router config dlsw timer icannotreach block time netbios cache timeout netbios explorer timeout netbios group cache netbios retry interval netbios verify interval sna cache timeout sna explorer timeout sna group cache sna retry interval sna verify interval time Configures DLSw timers Verifying DLSw Command See the DLSw Design and Implementation Guide Customization chapter and the Cisco IOS Bridging and IBM Networking
28. LC when connecting to X 25 networks QLLC essentially emulates SDLC over x 25 Therefore configuring QLLC devices is also complicated There are several considerations that affect which interface commands are configured See the DLSw Design and Implementation Guide for details You can configure DLSw for QLLC connectivity which enables both of the following scenarios Remote LAN attached devices physical units or SDLC attached devices can access an FEP or an AS 400 over an X 25 network Our QLLC support allows remote X 25 attached SNA devices to access an FEP without requiring X 25 NCP Packet Switching Interface NPSI in the FEP This may eliminate the requirement for NPSI if GATE and DATE are not required thereby eliminating the recurring license cost In addition because the QLLC attached devices appear to be Token Ring attached to the Network Control Program NCP they require no preconfiguration in the FEP Remote X 25 attached SNA devices can also connect to an AS 400 over Token Ring using this support Cisco 10S Bridging and IBM Networking Configuration Guide BC 294 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Task List Ti Remote X 25 attached SNA devices can access an FEP or an AS 400 over a Token Ring or over SDLC For environments just beginning to migrate to LANs our QLLC support allows deployment of LANs in remote sites while maintaining access to the FEP over existing NPSI link
29. LSw Translation Between Ethernet and Token Ring Configuration Example page 320 DLSw Translation Between FDDI and Token Ring Configuration Example page 321 DLSw Translation Between SDLC and Token Ring Media Example page 322 DLSw over Frame Relay Configuration Example page 324 DLSw over QLLC Configuration Examples page 325 DLSw with RIF Passthrough Configuration Example page 326 DLSw with Enhanced Load Balancing Configuration Example page 327 DLSw Peer Cluster Feature Configuration Example page 328 DLSW RSVP Bandwidth Reservation Feature Configuration Example page 329 DLSw RSVP Bandwidth Reservation Feature with Border Peers Configuration Example page 330 DLSw with Ethernet Redundancy Configuration Example page 331 DLSw with Ethernet Redundancy Enabled for Switch Support Configuration Example page 332 DLSw Using TCP Encapsulation and LLC2 Local Acknow ledgment Basic Configuration Example This sample configuration requires the following tasks which are described in earlier sections of this document Define a Source Bridge Ring Group for DLSw Define a DLSw Local Peer for the Router Define DLSw Remote Peers Assign DLSw to a local data link control Cisco 10S Bridging and IBM Networking Configuration Guide T BC 312 U A _Configuring Data Link Switching Plus DLSw Configuration Examples Figure 131 illustrates a DLSw configuration with local acknowledgment Because the RIF is terminated the r
30. Ring Traffic that originates from Token Ring is source route bridged from the local ring onto a source bridge ring group and then picked up by DLSw You must include a source bridge ring group command that specifies a virtual ring number when configuring Token Ring with DLSw In addition you must configure the source bridge command that tells the DLSw router to bridge from the physical Token Ring to the virtual ring To specify a virtual ring number use the following command in global configuration mode Command Purpose Router config source bridge ring group Defines a virtual ring ring group virtual mac address To enable DLSw to bridge from the physical Token Ring ring to the virtual ring use the following command in interface mode Command Purpose Router config if source bridge Defines SRB on interface source ring number bridge number target ring number To enable single route explorers use the following command in interface mode Command Purpose Router config if source bridge spanning Enables single route explorers Configuring the source bridge spanning command is required because DLSw uses single route explorers by default The following command configures a source bridge ring group and a virtual ring with a value of 100 to DLSw source bridge ring group 100 int TO source bridge 1 1 100 source bridge spanning The ring group number specified in the source bridge comman
31. a DLSw remote peer with Direct encapsulation with pass thru over Frame Relay disw remote peer 0 frame relay interface serial 01 pass thru DLSw Lite is described in the DLSw Lite Encapsulation section on page 291 DLSw Lite Encapsulation To configure DLSw Lite encapsulation use the following command in global configuration mode Command Purpose Router config dlsw remote peer lJist number frame relay interface serial number dlci number backup peer ip address frame relay interface serial number dlci number interface name bytes netbios out bytes list name circuit weight weight cost cost dest mac mac address dmac output list access list number host netbios out host list name keepalive seconds 1f size linger minutes lsap output list list pass thru Defines a remote peer with DLSw Lite encapsulation The following command specifies a DLSw remote peer with DLSw Lite encapsulation over Frame Relay disw remote peer 0 frame relay interface serial 01 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Task List Mapping DLSw to a Local Data Link Control In addition to configuring local and remote peers you must map one of the following local data link controls to DLSw Token Ring page 292 Ethernet page 293 SDLC page 293 QLLC page 294 FDDI page 295 Token
32. ac address dmac output list access list number host netbios out host list name inactivity dynamic keepalive seconds 1f size linger minutes lsap output list list no llc minutes passive priority rif passthru virtual ring number tcp queue max size timeout seconds Configures SNA DDR The following command configures the SNA DDR feature dlsw remote peer 0 tcp 10 2 13 4 keepalive 0 UDP Unicast Feature The UDP Unicast feature sends the SSP address resolution packets via UDP unicast service rather than TCP SSP packets include CANUREACH_EX NETBIOS_NQ_ex NETBIOS_ANQ and DATAFRAME The UDP unicast feature allows DLSw to better control address resolution packets and unnumbered information frames during periods of congestion Previously these frames were carried over TCP TCP resends frames that get lost or delayed in transit and hence aggravate congestion Because address resolution packets and unnumbered information frames are not sent on a reliable transport on the LAN sending them reliably over the WAN is unnecessary By using UDP for these frames DLSw minimizes network congestion Note UDP unicast enhancement has no affect on DLSw FST or direct peer encapsulation This feature is enabled by default To disable User Datagram Protocol UDP Unicast use the following command in global configuration mode Command Purpose Router config dlsw udp disable Disables UDP Unicast
33. ack 0 ip address 128 207 169 3 255 255 255 0 I interface tokenring 3 0 description fixed to flashnet ip address 128 207 2 152 255 255 255 0 ring speed 16 multiring all 1 interface tokenring 3 1 ip address 128 207 169 3 255 255 255 0 ring speed 16 source bridge 33 2 69 source bridge spanning i router igrp 777 network 128 207 0 0 Cisco IOS Bridging and IBM Networking Configuration Guide 78 11737 02 g Bc 315 Configuring Data Link Switching Plus E DLSw Configuration Examples DLSw Using TCP Encapsulation with Local Acknowledgment Peer Group Configuration Example 2 Figure 133 illustrates a peer group configuration that allows any to any connection except for Router B Router B has no connectivity to anything except router C because the promiscuous keyword is omitted Figure 133 DLSw with Peer Groups Specified Example 2 Router C Router Mainframe FE E 150 150 100 1 so 150 150 991 D 2 57 54 99 J 150 150 96 1 Router D 51 4 soL _ Router B ae So C4 a 50 150 98 1 o 150 150 97 1 SDLC 01 To Router E controller Group 2 3 Cc 5 51861 Router A hostname Router A source bridge ring group 2000 disw local peer peer id 150 150 99 1 group 2 promiscuous dlsw remote peer 0 tcp 150 150 100 1 I interface loopback 0 ip address 150 150 99 1 255 255 255 192 I interface tokenring 0 no ip address ring speed 16 source bridge 99 1 2000 source bri
34. al peer peer id 10 14 25 2 group 2 promiscuous dlsw rsvp default dlsw remote peer 0 tcp 10 3 16 2 The following output of the show ip rsvp sender command on DLSWRTR7 verifies that PATH messages are being sent from DLSWRTR2 DLSWRT2 show ip rsvp sender To From Pro DPort Sport Prev Hop I F BPS Bytes 10 2 17 1 10 14 25 2 TCP 2065 11003 10K 28K 10 14 25 2 10 2 07 1 TCP 11003 2065 10 2 17 1 Et1 1 10K 28K The following output of the show ip rsvp request command on DLSWRTR2 verifies that RESV messages are being sent from DLSWRTR 2 DLSWRT2 show ip rsvp req To From Pro DPort Sport Next Hop I F Fi Serv BPS Bytes 10 14 25 2 10 2 27 1 TCP 11003 2065 10 2 17 1 Et1 1 FF RATE 10K 28K Cisco 10S Bridging and IBM Networking Configuration Guide 5 330 iE wie _Configuring Data Link Switching Plus DLSw Configuration Examples W The following output of the show ip rsvp res command on the DLSWRTR verifies that the RSVP reservation was successful DLSWRTR1 show ip rsvp rese To From Pro DPort Sport Next Hop I F Fi Serv BPS Bytes 1022 07 1 10 14 25 2 TCP 2065 11003 10 14 25 2 Et1 1 FF RATE 10K 28K 10 14 25 2 10 2 17 1 TCP 11003 2065 FF RATE 10K 28K DLSw with Ethernet Redundancy Configuration Example Figure 144 shows that Router A Router B and Router C advertise their presence on the Ethernet via their Ethernet interfaces to the multicast MAC address 9999 9999 9999 Because Router B is the master router it keeps a database of all c
35. balancing fashion through the list of capable peers or ports If round robin is configured the router distributes the new circuit in a round robin fashion basing it s decision on which peer or port established the last circuit If enhanced load balancing is configured the router distributes new circuits based on existing loads and the desired ratio It detects the path that is underloaded in comparison to the other capable peers and will assign new circuits to that path until the desired ratio is achieved 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Task List For multiple peer connections peer costs must be applied The DLSw Enhanced Load Balancing feature works only with the lowest or equal cost peers For example if the user specifies dlswrtr1 diswrtr2 and dlswrtr3 with costs of 4 3 and 3 respectively DLSw establishes new circuits with only dlswrtr 2 and diswrtr3 To enable the DLSw Enhanced Load Balancing feature on the local router use the following command in global configuration mode Command Purpose Router config dlsw load balance round robin circuit count circuit weight Configures the DLSw Enhanced Load Balancing feature on the local router To adjust the circuit weight for a remote peer with TCP encapsulation use the following command in global configuration mode Command Purpose
36. ber peer but not both because of potential configuration confusion Cisco 10S Bridging and IBM Networking Configuration Guide 78 11737 02 E BC 297 Configuring Data Link Switching Plus E DLSw Configuration Task List Command To define peer groups configure border peers and assign the local peer to a peer cluster use the following command in global configuration mode Purpose Router config dl ip address group group border cost cost cluster cluster i seconds passive init pacing window size max pacing window size sw local peer peer id Enables peer groups and border peers d 1f size keepalive promiscuous biu segment Command Use the group keyword to define a peer group the border keyword to define a border peer and the cluster keyword to assign the local peer to a peer cluster When the user defines the cluster option in the dlsw local peer command on the member peer router the cluster information is exchanged with the border peer during the capabilities exchange as the peers become active The border peer uses this information to make explorer replication and forwarding decisions The following command configures the router as the Border peer that is a member of group 2 dlsw local peer peer id 10 2 13 4 group 2 border Configure the cluster option in the dlsw remote peer command on a border peer to enable the DLSw Peer Clusters feature without forcing every DLSw r
37. compliance mode with another vendor s router In particular enhancements that are locally controlled options on a router can be accessed even though the remote router does not have DLSw These include reachability caching explorer firewalls and media conversion Cisco IOS Bridging and IBM Networking Configuration Guide BC 306 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Task List Ti Netw ork Management There are several network management tools available to the user to help them more easily manage and troubleshoot their DLSw network CiscoWorks Blue Maps provides a logical view of the portion of your router network relevant to DLSw there is a similar tool for RSRB and APPN CiscoWorks Blue SNA View adds to the information provided by Maps by correlating SNA PU and LU names with DLSw circuits and DLSw peers CiscoWorks Blue Internetwork Status Monitor ISM support allows you to manage your router network from the mainframe console using IBM s NetView or Sterling s SOLVE Netmaster See the DLSw Design and Implementation Guide Using CiscoWorks Blue Maps SNA View and Internetwork Status Monitor chapter for more details Traffic Bandwidth and Queueing Management Access Control Cisco offers several bandwidth management and queueing features such as DLSw RSVP to enhance the overall performance of your DLSw network The queueing and bandwidth management features are described in detai
38. d hosts to be coming from the remote IBM machine In fact by looking at a trace from a protocol analyzer one cannot say whether a frame was acknowledged by the local router or by a remote IBM machine The MAC addresses and the RIFs generated by the Cisco IOS software are identical to those generated by the remote IBM machine The only way to find out whether a session is locally acknowledged is to use either a show local ack command or a show source bridge command on the router All the supervisory RR RNR REJ frames that are locally acknowledged go no farther than the router Without local acknowledgment for LLC2 every frame traverses the backbone With local acknowledgment only data I frames traverse the backbone resulting in less traffic on the backbone network For installations in which customers pay for the amount of traffic passing through the backbone this could be a definite cost saving measure A simple protocol exists between the two peers to bring up or down a TCP session Notes on Using LLC2 Local Acknowledgment LLC2 local acknowledgment is enabled with TCP and DLSw Lite remote peers If the LLC2 session between the local host and the router terminates in either router the other will be informed to terminate its connection to its local host If the TCP queue length of the connection between the two routers reaches the high water mark the routers sends Receiver Not Ready RNR messages to the local hosts until the queu
39. d must be the number of a defined source bridge ring group or DLSw will not see this interface Cisco 10S Bridging and IBM Networking Configuration Guide T BC 202 i wie _Configuring Data Link Switching Plus Ethernet Command DLSw Configuration Task List I Traffic that originates from Ethernet is picked up from the local Ethernet interface bridge group and transported across the DLSw network Therefore you must map a specific Ethernet bridge group to DLSw To map an Ethernet bridge group to DLSw use the following command in global configuration mode Purpose Router config dlsw bridge group group number Links DLSw to the bridge group of the Ethernet LAN llc2 N2 number Command ack delay time milliseconds ack max number idle time milliseconds local window number tl time milliseconds tbusy time milliseconds tpf time milliseconds trej time milliseconds txq max number xid neg val time milliseconds xid retry time milliseconds locaddr priority lu address priority list number sap priority priority list number To assign the Ethernet interface to a bridge group use the following command in interface configuration mode Purpose Router config if bridge group bridge group Assigns the Ethernet interface to a bridge group SDLC The following command maps bridge group 1 to DLSw dlsw bridge group 1 int El bridge group 1 bridge 1 protocol ieee Con
40. d routing was recently introduced in DLSw Version 2 but has been implemented in Cisco DLSw border peer technology since Cisco IOS Release 10 3 Expedited TCP Connection DLSw Version 2 efficiently establishes TCP connections Previously DLSw created two unidirectional TCP connections and then disconnected one after the capabilities exchange took place With DLSw Version 2 a single bidirectional TCP connection establishes if the peer is brought up as a result of an IP multicast UDP unicast information exchange DLSw Features DLSw is Cisco s version of DLSw and it supports several additional features and enhancements DLSw is a means of transporting SNA and NetBIOS traffic over a campus or WAN The end systems can attach to the network over Token Ring Ethernet Synchronous Data Link Control SDLC Protocol Qualified Logical Link Control QLLC or Fiber Distributed Data Interface FDDI See the DLSw Design and Implementation Guide Appendix B DLSw Support Matrix for details DLSw switches between diverse media and locally terminates the data links keeping acknowledgments keepalives and polling off the WAN Local termination of data links also eliminates data link control timeouts that can occur during transient network congestion or when rerouting around failed links Finally DLSw provides a mechanism for dynamically searching a network for SNA or NetBIOS resources and includes caching algorithms that minimize broadcast traff
41. dge spanning I router eigrp 202 network 150 150 0 0 Router B hostname Router B l source bridge ring group 2000 Cisco IOS Bridging and IBM Netw orking Configuration Guide T BC 316 i A _Configuring Data Link Switching Plus DLSw Configuration Examples W disw local peer peer id 150 150 98 1 group 2 dlsw remote peer 0 tcp 150 150 100 1 i interface loopback 0 ip address 150 150 98 1 255 255 255 192 1 interface serial 1 no ip address encapsulation sdlc no keepalive clockrate 9600 sdlc role primary sdlc vmac 4000 8888 0100 sdlc address 01 sdlc xid 01 05d20006 sdlc partner 4000 1020 1000 01 sdlc dlsw 1 interface tokenring 0 no ip address ring speed 16 source bridge 98 1 2000 source bridge spanning l router eigrp 202 network 150 150 0 0 Router C hostname Router C 1 source bridge ring group 2000 dlsw local peer peer id 150 150 100 1 group 2 border promiscuous dlsw remote peer 0 tcp 150 150 96 1 interface loopback 0 ip address 150 150 100 1 255 255 255 192 interface tokenring 0 no ip address ring speed 16 source bridge 500 1 2000 source bridge spanning I router eigrp 202 network 150 150 0 0 Router D hostname Router D source bridge ring group 2000 disw local peer peer id 150 150 96 1 group 1 border promiscuous dlsw remote peer 0 tcp 150 150 100 1 i interface loopback 0 ip address 150 150 96 1 255 255 255 192 I interface tokenring 0 0 no ip address ring speed 16 source bridge 9
42. e limit is reduced to below this limit It is possible however to prevent the RNR messages from being sent by using the dlsw llc2 nornr command The configuration of the LLC2 parameters for the local Token Ring interfaces can affect overall performance Refer to the chapter Configuring LLC2 and SDLC Parameters in this manual for more details about fine tuning your network through the LLC2 parameters The routers at each end of the LLC2 session execute the full LLC2 protocol which could result in significant router overhead The decision to use local acknowledgment for LLC2 should be based on the speed of the backbone network in relation to the Token Ring speed For LAN segments separated by slow speed serial links for example 56 kbps the T1 timer problem could occur more frequently In such cases it might be wise to turn on local acknowledgment for LLC2 For LAN segments separated by a T1 backbone delays will be minimal in such cases DLSw FST or direct encapsulation should be considered in order to disable local acknowledgement Speed mismatch between the LAN segments and the backbone network is one criterion to help you decide to use local acknowledgment for LLC2 There are some situations such as the receiving host failing between the time the sending host sends data and the time the receiving host receives it in which the sending host would determine at the LLC2 layer that data was received when it actually was not This error
43. e significant factor that limits the size of Token Ring internet works is the amount of explorer traffic that traverses the WAN DLSw includes the following features to reduce the number of explorers Peer Groups and Border Peers page 296 Explorer Firewalls page 300 NetBIOS Dial on Demand Routing page 300 SNA Dial on Demand Routing page 301 UDP Unicast Feature page 301 e LLC1 Circuits page 302 Dynamic Peers page 302 Promiscuous Peer Defaults page 302 Peer Groups and Border Peers Perhaps the most significant optimization in DLSw is a feature known as peer groups Peer groups are designed to address the broadcast replication that occurs in a fully meshed network When any to any communication is required for example for NetBIOS or Advanced Peer to Peer Networking APPN environments RSRB or standard DLSw implementations require peer connections between every pair of routers This setup is not only difficult to configure but it results in branch access routers having to replicate search requests for each peer connection This setup wastes bandwidth and router cycles A better concept is to group routers into clusters and designate a focal router to be responsible for broadcast replication This capability is included in DLSw With DLSw a cluster of routers in a region or a division of a company can be combined into a peer group Within a peer group one or more of the routers is designated to be the border
44. ed EXEC mode Command Purpose Router show running configuration Displays the running configuration of a device The global DLSw configuration statements including the dlsw local peer statement appear in the output before the interface configuration statements The following sample shows that DLSw is configured on router milan milan show run version 12 0 hostname Sample 1 source bridge ring group 110 dlsw local peer peer id 10 1 1 1 promiscuous 1 interface TokenRing0 0 no ip address ring speed 16 source bridge 222 1 110 source bridge spanning 1 Monitoring and Maintaining the DLSw Network To monitor and maintain activity on the DLSw network use one of the following commands in privileged EXEC mode as needed Command Purpose Router show dlsw capabilities interface type Displays capabilities of a direct encapsulated remote peer number Router show dlsw capabilities ip address Displays capabilities of a TCP FST remote peer ip address Router show dlsw capabilities local Displays capabilities of the local peer Router show dlsw circuits Displays DLSw circuit information Router show dlsw fastcache Displays the fast cache for FST and direct encapsulated peers Router show dlsw local circuit Displays DLSw circuit information when doing local conversion Router show dlsw peers Displays DLSw peer information Router show dlsw reachability Displays DLSw
45. er peer id 10 2 17 1 dlsw remote peer 0 tcp 10 3 2 1 dlsw transparent switch support interface loopback 0 ip address 10 2 17 1 255 255 255 0 int e 0 mac address 4000 0000 0001 ip address 150 150 2 1 255 255 255 0 dlsw transparent redundancy enable 9999 9999 9999 master priority dlsw transparent map local mac 4000 0001 0000 remote mac 4000 0010 0001 neighbor 4000 0000 0011 dlsw transparent timers sna 1500 Router B dlsw local peer peer id 10 2 17 2 dlsw remote peer 0 tcp 10 3 2 1 dlsw transport switch support interface loopback 0 ip address 10 2 17 2 255 255 255 0 int e 1 mac address 4000 0000 0011 ip address 150 150 3 1 255 255 255 0 dlsw transparent redundancy enable 9999 9999 9999 dlsw transparent map local mac 4000 0201 0001 remote mac 4000 0010 0001 neighbor 4000 0000 0001 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Examples Cisco IOS Bridging and IBM Networking Configuration Guide PBC334 E 78 11737 02
46. ests from those routers that are not preconfigured Setting the dlsw prom peer defaults command allows the user to determine various settings for the promiscuous transport Cisco 10S Bridging and IBM Networking Configuration Guide ka 78 11737 02 _Configuring Data Link Switching Plus Command DLSw Configuration Task List Ti To configure promiscuous peer defaults use the following command in global configuration mode Purpose Router config dlsw prom peer defaults Configures promiscuous peer defaults bytes netbios out bytes list name cost cost dest mac destination mac address dmac output list access list number host netbios out host list name keepalive seconds 1f size tcep queue max size lsap output list list Availability DLSw supports the following features that allow it to dynamically finds alternate paths quickly and optionally load balances across multiple active peers ports and channel gateways Load Balancing page 303 Ethernet Redundancy page 305 Backup Peers page 305 Load Balancing DLSw offers enhanced availability by caching multiple paths to a given MAC address or NetBIOS name where a path is either a remote peer or a local port Maintaining multiple paths per destination is especially attractive in SNA networks A common technique used in the hierarchical SNA environment is assigning the same MAC address to different Token Ring interface couplers TICs on
47. f dlsw transparent Configures a single destination MAC address to which multiple MAC map local mac mac address remote mac addresses on a transparent bridged are mapped mac address neighbor mac address The Ethernet Redundancy feature is a complex feature See the DLSw Design and Implementation Guide for more details Refer to the DLSw with Ethernet Redundancy Configuration Example section on page 331 and the DLSw with Ethernet Redundancy Enabled for Switch Support Configuration Example section on page 332 for sample configurations Backup Peers The backup peer option is common to all encapsulation types on a remote peer and specifies that this remote peer is a backup peer for the router with the specified IP address Frame Relay Data Link Control Identifier DLCI number or interface name When the primary peer fails all circuits over this peer are disconnected and the user can start a new session via their backup peer Prior to Cisco IOS Release 11 2 6 F you could configure backup peers only for primary FST and TCP Also when you specify the backup peer option in a dlsw remote peer tcp command the backup peer is activated only when the primary peer becomes unreachable Once the primary peer is reactivated all new sessions use the primary peer and the backup peer remains active only as long as there are LLC2 connections using it You can use the linger option to specify a period in minutes that the backup peer remain
48. figuring SDLC devices is more complicated than configuring Ethernet and Token Ring There are several considerations that affect which interface commands are configured See the DLSw Design and Implementation Guide for more details To establish devices as SDLC stations use the following commands in interface configuration mode Command Purpose Stepl Router config if encapsulation Sets the encapsulation type of the serial interface to SDLC sdlc Step2 Router config if sdlc role none Establishes the role of the interface primary secondary prim xid poll Step3 Router config if sdlce vmac Configures a MAC address for the serial interface mac address Step4 Router config if sdlc address Assigns a set of secondary stations attached to the serial link hexbyte echo Step5 Router config if sdlc partner Specifies the destination address with which an LLC session is mac address sdlc address inbound established for the SDLC station outbound Cisco IOS Bridging and IBM Networking Configuration Guide 78 11737 02 E BC 293 Configuring Data Link Switching Plus E DLSw Configuration Task List Command Purpose Step6 Router config if sdle xid Specifies an XID value appropriate for the designated SDLC station associated with this serial interface Step7 Router config if sdle dlsw Enables DLSw on an SDLC interface sdlc address default partner mac address inbound outbou
49. he router for SRB configure the FDDI interface for Token Ring If you are configuring the router for Transparent Bridging configure the FDDI interface for Ethernet Configuring Advanced Features DLSw goes beyond the standard to include additional functionality in the following areas Scalability page 296 Constructs IBM internetworks in a way that reduces the amount of broadcast traffic which enhances their scalability Availability page 303 Dynamically finds alternate paths and optionally load balances across multiple active peers ports and channel gateways 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Task List Scalability Modes of Operation page 306 Dynamically detects the capabilities of the peer router and operates according to those capabilities Network Management page 307 Works with enhanced network management tools such as CiscoWorks Blue Maps CiscoWorks SNA View and CiscoWorks Blue Internetwork Status Monitor ISM Traffic Bandwidth and Queueing Management page 307 Offers several bandwidth management and queueing features to enhance the overall performance of your DLSw network Controls different types of explorer traffic using multiple queues each with a wide range of depth settings Access Control page 307 Provides access control to various resources throughout a network On
50. how ip rsvp res command to verify that a reservation was made from DLSWRTR1 to DLSWRTR2 DLSWRTR2 show ip rsvp rese To From Pro DPort Sport Next Hop I F Fi Serv BPS Bytes 10 2 17 1 10 2 24 3 TCP 2065 11003 10 2 17 1 Et1 1 FF RATE 10K 28K 10 2 24 3 10 2 17 1 TCP 11003 2065 FF RATE 10K 28K 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Examples DLSw RSVP Bandwidth Reservation Feature w ith Border Peers Configuration Example Figure 143 shows a DLSw border peer network configured with DLSw RSVP Figure 143 DLSw RSVP Bandwidth Reservation Feature in a Border Peer Network DLSW RTR 1 IPRTR1 IPRTR2 DLSW RTR 2 i Fm T 7 i Pm oT Fm T Token z z i i ZS AS Token Cp 2ty 2 yp z UD 10 2 17 1 10 3 15 2 10 3 16 2 10 14 25 2 Workstation 1 Workstation 2 15 A iin Group 1 Group 2 The following example configures DLSWRTR1 to send PATH messages at rates of 40 kbps and 10 kbps and DLSWRTR2 to send PATH messages at rates of 10 DLSWRTR1 dlsw local peer peer id 10 2 17 1 group 1 promiscuous dlsw rsvp default dlsw remote peer 0 tcp 10 3 15 2 dlsw peer on demand defaults rsvp 40 10 IPRTR1 disw local peer peer id 10 3 15 2 group 1 border promiscuous dlsw remote peer 0 tcp 10 3 16 2 IPRTR2 disw local peer peer id 10 3 16 2 group 2 border promiscuous dlsw remote peer 0 tcp 10 3 15 2 DLSWRTR2 disw loc
51. ic DLSw is fully compatible with any vendor s RFC 1795 implementation and the following features are available when both peers are using DLSw Peer groups and border peers Backup peers e Promiscuous and on demand peers Explorer firewalls and location learning e NetBIOS dial on demand routing feature support 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide BC 283 Configuring Data Link Switching Plus E Technology Overview UDP unicast support Load balancing Support for LLC1 circuits Support for multiple bridge groups Support for RIF Passthrough SNA type of service feature support Local acknowledgment for Ethernet attached devices and media conversion for SNA PU 2 1 and PU 2 0 devices Conversion between LLC2 to SDLC between PU 4 devices Local or remote media conversion between LANs and either SDLC Protocol or QLLC SNA View Blue Maps and Internetwork Status Monitor ISM support MIB enhancements that allow DLSw features to be managed by the CiscoWorks Blue products SNA Maps and SNA View Also new traps alert network management stations of peer or circuit failures For more information refer to the current Cisco IOS release note for the location of the Cisco MIB website Local Acknowledgment When you have LANs separated by wide geographic distances and you want to avoid sending data multiple times and the loss of user sessions that can occur with
52. ing group numbers do not have to be the same Figure 131 DLSw with Local Acknowledgment Simple Configuration y Router A A Token a Ring 25 37x5 10 2 25 1 Ring Group Ring Group 10 12 83241 3x74 Router A source bridge ring group 10 I dlsw local peer peer id 10 2 25 1 dlsw remote peer 0 tcp 10 2 5 2 interface loopback 0 ip address 10 2 25 1 255 255 255 0 I interface tokenring 0 no ip address ring speed 16 source bridge 25 1 10 source bridge spanning Router B source bridge ring group 12 dlsw local peer peer id 10 2 5 2 dlsw remote peer 0 tcp 10 2 25 1 interface loopback 0 ip address 10 2 5 2 255 255 255 0 I interface tokenring 0 no ip address ring speed 16 source bridge 5 1 12 source bridge spanning 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide pg Configuring Data Link Switching Plus E DLSw Configuration Examples DLSw Using TCP Encapsulation with Local Acknowledgment Peer Group Configuration Example 1 Figure 132 illustrates border peers with TCP encapsulation Router A is configured to operate in promiscuous mode and border peers Routers B and C forward broadcasts This configuration reduces processing requirements in Router A the access router and still supports any to any networks Configure Border peer B and C so that they peer to each other Figure 132 DLSw with Peer Groups Specified Example 1 Token Ring 3 Router A
53. ircuits handled within the domain and grants or denies permission for new circuit requests for Router A and Router C There is no special configuration required for the end stations or for the remote peer Only the DLSw devices on the LAN need the extra configuration Master Router B waits 1 5 seconds after it receives the first IWANTIT primitive before assigning the new SNA circuit to one of its ethernet redundancy peers because of the dlsw transparent timers sna 7500 command Figure 144 DLSw with Ethemet Redundancy Workstation X Hi C CJ T Router A Router B Router C D Router D 17955 Router A dlsw local peer peer id 10 2 24 2 dlsw remote peer 0 tcp 10 2 17 1 interface loopback 0 ip address 10 2 24 2 255 255 255 0 int el ip address 150 150 2 1 255 255 255 0 dlsw transparent redundancy enable 9999 9999 9999 Router B dlsw local peer peer id 10 2 24 3 78 11737 02 Cisco 10S Bridging and IBM Networking Configuration Guide pg Configuring Data Link Switching Plus E DLSw Configuration Examples dlsw remote peer 0 tcp 10 1 17 1 interface loopback 0 ip address 10 2 24 3 255 255 255 0 int el ip address 150 150 2 2 255 255 255 0 dlsw transparent redundancy enable 9999 9999 9999 master priority 1 dlsw transparent timers sna 1500 Router C disw local peer peer id 10 2 24 4 dlsw remote peer 0 tcp 10 2 17 1 interface loopback 0 ip address 10 2 24 4 255 255 255 0 int el ip address 150
54. l in the DLSw Design and Implementation Guide Bandwidth Management Queueing chapter DLSw offers the following features that allow it to control access to various resources throughout a network DLSw Ring List or Port List page 307 DLSw Bridge Group List page 308 Static Paths page 309 Static Resources Capabilities Exchange page 309 Filter Lists in the Remote Peer Command page 309 DLSw Ring List or Port List Command DLSw ring lists map traffic on specific local rings to remote peers You can create a ring list of local ring numbers and apply the list to remote peer definitions Traffic received from a remote peer is only forwarded to the rings specified in the ring list Traffic received from a local interface is only forwarded to peers if the input ring number appears in the ring list applied to the remote peer definition The definition of a ring list is optional If you want all peers and all rings to receive all traffic you do not have to define a ring list Simply specify 0 for the list number in the remote peer statement To define a ring list use the following command in global configuration mode Purpose Router config dlsw ring list list number rings Defines a ring list ring number DLSw port lists map traffic on a local interface either Token Ring or serial to remote peers Port lists do not work with Ethernet interfaces or any other interface types connected to DLSw by mea
55. leged EXEC mode Command Purpose Router clear dlsw statistics Resets to zero the number of frames that have been processed in the local remote and group caches To disable the border peer caching feature use the following command in global configuration mode Command Purpose Router config if dlsw group cache disable Disables the border peer caching feature To verify that the peer cluster feature is enabled or that the border peer is configured issue the show dlsw capabilities command on the router To verify the cluster id number of which the peer is a member issue the show dlsw capabilities local command on the local router 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide BC 299 Configuring Data Link Switching Plus E DLSw Configuration Task List To display the contents of the reachability caches use the following command in privileged EXEC command mode Command Purpose Router show dlsw reachability group value Displays content of group local and remote caches local remote mac address address netbios names name Command Use the group keyword to display the reachability information for the border peer Explorer Firewalls An explorer firewall permits only a single explorer for a particular destination MAC address or NetBIOS name to be sent across the WAN While an explorer is outstanding and awaiting a response from the
56. llowing command specifies a DLSw remote peer with FST encapsulation dlsw remote peer 0 fst 10 2 23 5 Cisco IOS Bridging and IBM Networking Configuration Guide BC 290 78 11737 02 _Configuring Data Link Switching Plus Direct Encapsulation DLSw Configuration Task List Ti To configure direct encapsulation use the following command in global configuration mode Command Purpose Router config dlsw remote peer lJist number frame relay interface serial number dlci number backup peer ip address frame relay interface serial number dlci number interface name bytes netbios out bytes list name circuit weight weight cost cost dest mac mac address dmac output list access list number host netbios out host list name keepalive seconds 1f size Linger minutes lsap output list list pass thru Defines a remote peer with direct encapsulation Direct encapsulation is supported over High Level Data Link Control HDLC and Frame Relay The following command specifies a DLSw remote peer with direct encapsulation over HDLC dlsw remote peer 0 interface serial 01 Direct encapsulation over Frame Relay comes in two forms DLSw Lite LLC2 encapsulation and Passthrough Specifying the pass thru option configures the router so that the traffic will not be locally acknowledged DLSw normally locally acknowledges traffic to keep traffic on the WAN to a minimum The following command specifies
57. n an SNA network SNASw over DLSw allows Cisco s APPN Branch Extender functionality to be used in conjunction with DLSw in the same router With this feature DLSw can be used to access SNASw in the data center DLSw can also be used as a transport for SNASw upstream connectivity providing nondisruptive recovery from failures Using DLSw as a transport for other Cisco IOS SNA features requires a feature called VDLC Cisco IOS data link users such as LNM DSPU SNA service point and SNASw write to a virtual data link control interface DLSw then reads from this interface and sends out the traffic Similarly DLSw can receive traffic destined for one of these data link users and write it to the virtual data link control interface from which the appropriate data link user will read it In Figure 129 SNASw and DLSw use Token Ring and Ethernet respectively as real data link controls and use virtual data link control to communicate between themselves When one of the high layer protocols passes data to the virtual data link control the virtual data link control must pass it to a higher layer protocol nothing leaves the virtual data link control without going through a data link user 78 11737 02 Cisco 10S Bridging and IBM Networking Configuration Guide BC 287 Configuring Data Link Switching Plus E DLSw Configuration Task List Figure 129 VDLC Interaction with HigherLayer Protocols
58. n or path of a static MAC address ring number remote peer interface serial number ip address ip address rif rif string group group or or Router config dlsw netbios name netbios name Configures a static NetBIOS name ring ring number remote peer interface serial number ip address ip address rif rif string group group Static Resources Capabilities Exchange To reduce explorer traffic destined for this peer the peer can send other peers a list of resources for which it has information icanreach or does not have information icannotreach This information is exchanged as part of a capabilities exchange To configure static resources that will be exchanged as part of a capabilities exchange use one of the following commands in global configuration mode as needed Command Purpose Router config dlsw icannotreach saps sap Configures a resource not locally reachable by the router sap or en Router config dlsw icanreach mac exclusive netbios exclusive mac address mac addr mask mask netbios name name saps Configures a resource locally reachable by the router Filter Lists in the Remote Peer Command The dest mac and dmac output list options allow you to specify filter lists as part of the dlsw remote peer command to control access to remote peers For static peers in direct FST or TCP encapsulation these filters control which explorers are sent to remote peers
59. nd 1 The last byte of the MAC address must be 00 QLLC Use the default option if you have more than 10 SDLC devices to attach to the DLSw network To configure an SDLC multidrop line downstream you configure the SDLC role as either primary or prim xid poll SDLC role primary specifies that any PU without the xid poll parameter in the sdlc address command is a PU 2 0 device SDLC role prim xid poll specifies that every PU is type 2 1 We recommend that you specify sdlc role primary if all SDLC devices are type PU 2 0 or a mix of PU 2 0 and PU 2 1 Specify sdlc role prim xid poll if all devices are type PU 2 1 To configure DLSw to support LLC2 to SDLC conversion for PU 4 or PU 5 devices specify the echo option in the sdlc address command A PU 4 to PU 4 configuration requires that none be specified in the sdlc role command Refer to the DLSw with SDLC Multidrop Support Configuration Examples section on page 318 and the DLSw with LLC2 to SDLC Conversion Between PU 4 to PU 4 Communication Example section on page 319 for sample configurations The following configuration shows a DLSw router configured for SDLC dlsw local peer peer id 10 2 2 2 dlsw remote peer 0 tcp 10 1 1 1 interface Seriall mtu 6000 no ip address encapsulation sdlc no keepalive nrzi encoding clockrate 9600 sdlc vmac 4000 3745 0000 sdlc N1 48016 sdlc address 04 echo sdlc partner 4000 1111 0020 04 sdlic dlsw 4 SNA devices use QL
60. nd Implementation Guide for details on how to configure load balancing in DLSw Refer to the DLSw with Enhanced Load Balancing Configuration Example section on page 327 for a sample configuration Cisco 10S Bridging and IBM Networking Configuration Guide BC 304 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Task List Ti Ethernet Redundancy The DLSw Ethernet Redundancy feature introduced in Cisco IOS Release 12 0 5 T provides redundancy and load balancing between multiple DLSw peers in an Ethernet environment It enables DLSw to support parallel paths between two points in an Ethernet environment ensuring resiliency in the case of a router failure and providing load balancing for traffic load The feature also enables DLSw to support multiple DLSw routers on the same transparent bridged domain that can reach the same MAC address in a switched environment To enable the DLSw Ethernet Redundancy feature issue the following command in interface configuration mode Command Purpose Router config if dlsw transparent Configures transparent redundancy redundancy enable Command To enable the DLSw Ethernet Redundancy feature in a switched environment enter the following commands in interface configuration mode Purpose Stepl Router config if dlsw transparent Enables DLSw Ethernet Redundancy feature when using a switch switch support device Step2 Router config i
61. ns of a bridge group You can create a port list of local ports and apply the list to remote peer definitions Traffic received from a remote peer is only forwarded to peers if the input port number appears in the port list applied to the remote peer definition The port list command provides a single command to specify both serial and Token Ring interfaces Figure 130 shows how port lists are used to map traffic 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Task List Command Figure 130 Mapping Traffic Using Port Lists Explorer Z Token 4 ZA K y Ring i o Peer B i p o ty Peer C E 51860 Peer B Port list 1 Peer C Port list 2 The definition of a port list is optional If you want all peers and all interfaces to receive all traffic you do not have to define a port list Simply specify 0 for the list number in the remote peer statement To define a port list use the following command in global configuration mode Purpose Router config dlsw port list list number type number Defines a port list amp Note Command Either the ring list or the port list command can be used to associate rings with a given ring list The ring list command is easier to type in if you have a large number of rings to define DLSw Bridge Group List DLSw bridge group lists map traffic on
62. occurs because the router acknowledges that it received data from the sending host before it determines that the receiving host can actually receive the data But because both NetBIOS and SNA have error recovery in situations where an end device goes down these higher level protocols will resend any missing or lost data Because these transaction request confirmation protocols exist above LLC2 they are not affected by tight timers as is LLC2 They also are transparent to local acknowledgment Cisco 10S Bridging and IBM Networking Configuration Guide BC 286 78 11737 02 _Configuring Data Link Switching Plus L Note Technology Overview W If you are using NetBIOS applications note that there are two NetBIOS timers one at the link level and one at the next higher level Local acknowledgment for LLC2 is designed to solve link timeouts only If you are experiencing NetBIOS session timeouts you have two options Experiment with increasing your NetBIOS timers and decreasing your maximum NetBIOS frame size Avoid using NetBIOS applications on slow serial lines By default the Cisco IOS software translates Token Ring LLC2 to Ethernet 802 3 LLC2 To configure the router to translate Token Ring LLC2 frames into Ethernet 0x80d5 format frames refer to the section Enable Token Ring LLC2 to Ethernet Conversion in the Configuring Source Route Bridging chapter of the Cisco IOS Bridging and IBM Networking Command Refe
63. outer in the network to upgrade their software To enable the DLSw Peer Clusters feature on a Border Peer use the following command in global configuration mode Purpose Router config dlsw remote peer list number tcp ip address backup peer ip address frame relay interface serial number dlci number interface name bytes list name circuit weight weight cluster cluster id cost cost dest mac mac address dmac output list access list number host list name inactivity dynamic keepalive seconds lsap output list list no llc minutes passive priority rif passthru virtual ring number tcp queue max size timeout seconds Defines the border peer router as part of a particular cluster and enables the DLSw Peer Clusters feature bytes netbios out host netbios out 1f size linger minutes The following command configures a border router as a member of cluster 5 dlsw remote peer tcp 10 2 13 5 cluster 5 A peer on demand peer is a non configured remote peer that was connected because of an LLC2 session established through a border peer DLSw network On demand peers greatly reduce the number of peers that must be configured You can use on demand peers to establish an end to end circuit even though the DLSw routers servicing the end systems have no specific configuration information about the peers This configuration permits casual any to any connection without the burden of
64. peer Instead of all routers peering to one another each router within a group peers to the border peer and border peers establish peer connections with each other When a DLSw router receives a TEST frame or NetBIOS NAME QUERY it sends a single explorer frame to its border peer The DLSw border peer router checks its local remote and group cache for any reachability information before forwarding the explorer If no match is found the border peer forwards the explorer on behalf of the peer group member If a match is found the border peer sends the explorer to the appropriate peer or border peer This setup eliminates duplicate explorers on the access links and minimizes the processing required in access routers You can further segment DLSw routers within the same border peer group that are serving the same LANs into a peer cluster This segmentation reduces explorers because the border peer recognizes that it only has to forward an explorer to one member within a peer cluster Only TCP encapsulation can be used with the DLSw Peer Clusters feature Cisco 10S Bridging and IBM Networking Configuration Guide BC 296 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Task List I The DLSw Peer Clusters feature is configured locally on the member peer or on a border peer Although both options can be configured we recommend that the cluster id of a particular peer is defined in either the border peer or on the mem
65. peration It is sometimes necessary for DLSw and RSRB to coexist in the same network and in the same router for example during migration from RSRB to DLSw Cisco DLSw supports this environment In addition DLSw must also interoperate with other vendors implementations that are based upon other DLSw RFC standards such as DLSw Version 1 and Version 2 Cisco routers implementing Cisco DLSw automatically supports three different modes of operation Dual mode A Cisco router can communicate with some remote peers using RSRB and with others using DLSw providing a smooth migration path from RSRB to DLSw in dual mode RSRB and DLSw coexist on the same box the local peer must be configured for both RSRB and DLSw and the remote peers must be configured for either RSRB or DLSw but not both Standards compliance mode DLSw can detect automatically via the DLSw capabilities exchange if the participating router is manufactured by another vendor therefore operating in DLSw standard mode DLSw Version 1 RFC 1795 and DLSw Version 2 RFC 2166 Enhanced mode DLSw can detect automatically that the participating router is another DLSw router therefore operating in enhanced mode making all of the features of DLSw available to the SNA and NetBIOS end systems Note DLSw does not interoperate with the DLSw RFC 1434 standard Some enhanced DLSw features are also available when a Cisco router is operating in standards
66. re 142 shows a DLSw network with the DLSw RSVP Bandwidth Reservation feature configured Figure 142 DLSw RSVP Bandwidth Reservation Feature Configured Token Ring gt aa Workstation 1 eo _Fo _ amp gt o OCJ DLSW RTR 1 IP RTR 1 IP RTR 2 DLSW RTR 2 An 10 2 17 1 10 1 15 2 10 1 16 2 10 2 24 3 D a CJ C Workstation 2 Workstation 3 Workstation 4 D DLSWRTR 1 and DLSWRTR 2 are configured for the DLSw RSVP Bandwidth Reservation feature with an average bit rate of 40 and a maximum burst rate of 10 DLSWRTR 1 dlsw local peer peer id 10 2 17 1 dlsw remote peer 0 tcp 10 2 24 3 dlsw rsvp 40 10 DLSWRTR2 disw local peer peer id 10 2 24 3 dlsw remote peer 0 tcp 10 2 17 1 dlsw rsvp 40 10 The following output of the show ip rsvp sender command on the DLSWRTR2 verifies that PATH messages are being sent from DLSWRTR2 DLSWRTR2 show ip rsvp sender To From Pro DPort Sport Prev Hop I F BPS Bytes 10 2 17 1 10 2 24 3 TCP 2065 11003 10K 28K 10 2 24 3 10 2 17 1 TCP 11003 2065 10 2 17 1 Et1 1 10K 28K The following output of the show ip rsvp req command on the DLSWRTR2 verifies that RESV messages are being sent from DLSWRTR2 DLSWRTR2 show ip rsvp req To From Pro DPort Sport Next Hop I F Fi Serv BPS Bytes 10 2 24 3 102417 1 TCP 11003 2065 10 2 17 1 Et1 1 FF RATE 10K 28K If the IP cloud is able to guarantee the bandwidth requested and the show ip rsvp sender and show ip rsvp req commands are successful issue the s
67. rence Volume 1 of 2 DLSw Support for Other SNA Features DLSw can be used as a transport for SNA features such as LNM DSPU SNA service point and SNA Switching Services SNASw through a Cisco IOS feature called virtual data link control VDLC LNM over DLSw allows DLSw to be used in Token Ring networks that are managed by IBM s LNM software Using this feature LNM can be used to manage Token Ring LANs control access units and Token Ring attached devices over a DLSw network All management functions continue to operate as they would in a source route bridged network or an RSRB network DSPU over DLSw allows Cisco s DSPU feature to operate in conjunction with DLSw in the same router DLSw can be used either upstream toward the mainframe or downstream away from the mainframe of DSPU DSPU concentration consolidates the appearance of multiple PUs into a single PU appearance to VTAM minimizing memory and cycles in central site resources VTAM NCP and routers and speeding network startup SNA service point over DLSw allows Cisco s SNA service point feature to be used in conjunction with DLSw in the same router Using this feature SNA service point can be configured in remote routers and DLSw can provide the path for the remote service point PU to communicate with NetView This allows full management visibility of resources from a NetView 390 console while concurrently offering the value added features of DLSw i
68. s Remote LAN attached devices physical units or SDLC attached devices can access a FEP over an X 25 network without requiring X 25 hardware or software in the LAN attached devices The Cisco IOS software supports direct attachment to the FEP over X 25 without the need for routers at the data center for SNA traffic To enable QLLC connectivity for DLSw use the following commands in interface configuration mode Command Purpose Step1 Router config if encapsulation x Specifies an interface as an X 25 device 25 Step2 Router config if x25 address Activates X 25 subaddresses subaddress Step3 Router config if x25 map qllc Associates a virtual MAC address with the X 121 address of the remote virtual mac addr x121 addr X 25 device cud cud value x25 map options Step4 Router config if qlle dlsw Enables DLSw over QLLC subaddress subaddress pve pvc low pvc high poolsize partner macaddr sap ssap dsap xid xidstring npsi pol1 FDDI vmac vmacaddr partner The following configuration enables QLLC connectivity for DLSw disw local peer peer id 10 3 12 7 dlsw remote peer 0 tcp 10 3 1 4 interface SO encapsulation x25 x25 address 3110212011 x25 map qlic 1000 0000 0001 3 1104150101 qllc dlsw partner 4000 1151 1234 Configure an FDDI interface the same as a Token Ring or Ethernet interface depending on whether you are configuring SRB or Transparent Bridging If you are configuring t
69. s connected after the connection to the primary peer is reestablished When the linger period expires the backup peer connection is taken down 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Configuring Data Link Switching Plus E DLSw Configuration Task List amp Note If the linger keyword is set to 0 all existing sessions on the backup router immediately drop when the primary recovers If the linger keyword is omitted all existing sessions on the backup router remain active as long as the session is active when the primary recovers however all new sessions establish via the primary peer If the linger keyword is set to x minutes all existing sessions on the backup router remain active for x minutes once the primary recovers however all new sessions establish via the primary peer Once x minutes expire all existing sessions on the backup router drop and the backup peer connection is terminated The linger keyword can be used to minimize line costs if the backup peer is accessed over dial lines but can be set high enough to allow an operator warning to be sent to all the SNA end users It will not however pass explorers and will not create any new circuits while the primary is up To configure a backup peer use the following command in global configuration mode Command Purpose Router config dlsw remote peer backup peer Configures a backup peer ip address M odes of O
70. several factors including whether you want to terminate the LLC flows TCP and DLSw Lite terminate the LLC but the other encapsulation types do not For details on each encapsulation type see the DLSw Design and Implementation Guide See the Local Acknowledgement section in the overview chapter of this publication for a discussion on local acknowledgement TCP Encapsulation To configure TCP encapsulation on a remote peer use the following command in global configuration mode Command Purpose Router config dlsw remote peer list number tcp Defines a remote peer with TCP encapsulation ip address ip address frame relay interface serial number dlci number interface name bytes netbios out bytes list name circuit weight weight cluster cluster id cost cost dest mac mac address dmac output list access list number host netbios out host list name inactivity dynamic keepalive seconds lf size linger minutes lsap output list list no llc minutes passive priority rif passthru virtual ring number tcp queue max size timeout seconds The following command specifies a dlsw remote peer with TCP encapsulation dlsw remote peer 0 tcp 10 23 4 5 78 11737 02 Cisco 10S Bridging and IBM Networking Configuration Guide BC 289 Configuring Data Link Switching Plus E DLSw Configuration Task List TCP IP with RIF Passthrough Encapsulation To configure TCP IP with RIF Pa
71. ss ring speed 16 source bridge 400 1 2000 Cisco 10S Bridging and IBM Networking Configuration Guide 78 11737 02 EEN Configuring Data Link Switching Plus E DLSw Configuration Examples source bridge spanning i router eigrp 202 network 150 150 0 0 DLSw over Frame Relay Configuration Example Frame Relay support extends the DLSw capabilities to include Frame Relay in direct mode Frame Relay support includes permanent virtual circuit capability DLSw runs over Frame Relay with or without local acknowledgement It supports the Token Ring to Token Ring connections similar to FST and other direct data link controls Figure 138 illustrates a DLSw configuration over Frame Relay with RIF Passthrough Figure 138 DLSw over Frame Relay End station Router A Router B End station Token eS Frame Relay A ts Ring i y Network y Ring Oo Oo lt Frame Relay _ gt Session lt Direct Session gt 3704 The following configuration examples are based on Figure 139 The Token Rings in the illustration are in Ring 2 Router A source bridge ring group 100 dlsw local peer 10 2 23 1 dlsw remote peer 0 frame relay interface serial 0 30 passthru interface loopback 0 ip address 10 2 23 1 255 255 255 0 interface tokenring 0 ring speed 16 source bridge spanning 1 1 100 I interface serial 0 mtu 3000 no ip address encapsulation frame relay frame relay lmi type ansi
72. ssthrough encapsulation use the following command in global configuration mode Command Purpose Router config dlsw remote peer list number tcp ip address backup peer ip address frame relay interface serial number dlci number interface name bytes netbios out bytes list name circuit weight weight cost cost dest mac mac address dmac output list access list number host netbios out host list name inactivity dynamic keepalive seconds 1f size linger minutes lsap output list list no llc minutes passive priority rif passthru virtual ring number tcp queue max size timeout seconds Defines a remote peer with TCP IP with RIF Passthrough encapsulation The following command specifies a remote peer with TCP IP with RIF Passthrough encapsulation dlsw remote peer 0 tcp 10 2 23 5 rif passthru 100 FST Encapsulation To configure FST encapsulation on a remote peer use the following command in global configuration mode Command Purpose Router config dlsw remote peer list number fst ip address backup peer ip address frame relay interface serial number dlci number interface name bytes netbios out bytes list name circuit weight weight cost cost dest mac mac address dmac output list access list number host netbios out host list name keepalive seconds 1f size linger minutes lsap output list list Defines a remote peer with FST encapsulation The fo
73. ssthrough feature Figure 139 Network Configuration with RIF Passthrough NR NRS 100 100 a lias B Router A source bridge ring group 100 dlsw local peer peer id 10 1 12 1 dlsw remote peer 0 tcp 10 1 14 2 rif passthru 100 interface loopback 0 ip address 10 1 12 1 255 255 255 0 interface tokenring 0 ring speed 16 source bridge 25 1 100 source bridge spanning Router B source bridge ring group 100 dlsw local peer peer id 10 1 14 2 dlsw remote peer 0 tcp 10 1 12 1 rif passthru 100 interface loopback 0 ip address 10 1 14 2 255 255 255 0 interface tokenring 0 ring speed 16 source bridge 51 1 100 source bridge spanning Cisco IOS Bridging and IBM Netw orking Configuration Guide PBC 326 E 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Examples W DLSw with Enhanced Load Balancing Configuration Example Figure 140 shows DLSw with the Enhanced Load Balancing feature Figure 140 DLSw with Enhanced Load Balancing __ Token ee r Ring i p 4 y RTRA RTRC 51972 Router A is configured for the DLSw Enhanced Load Balancing feature to load balance traffic among the DLSw remote peers B C and D Router A dlsw local peer 10 2 19 1 dlsw remote peer 0 tcp 10 2 24 2 circuit weight 10 dlsw remote peer 0 tcp 10 2 19 5 circuit weight 6 dlsw remote peer 0 tcp 10 2 20 1 circuit weight 20 dlsw load balance circuit count dlsw timer explorer wait
74. the IBM FEPs DLSw ensures that duplicate TIC addresses are found and if multiple DLSw peers can be used to reach the FEPs they are cached The way that multiple capable peers are handled with DLSw can be configured to meet either of the following network needs Fault tolerance To rapidly reconnect if a data link connection is lost If load balancing is not enabled the Cisco IOS software by default maintains a preferred path and one or more capable paths to each destination The preferred path is either the peer or port that responds first to an explorer frame or the peer with the least cost If the preferred path to a given destination is unavailable the next available capable path is promoted to the new preferred path No additional broadcasts are required and recovery through an alternate peer is immediate Maintaining multiple cache entries facilitates a timely reconnection after session outages A peer with the least cost can also be the preferred path You can specify cost in either the dlsw local peer or dlsw remote peer commands See the DLSw Design and Implementation Guide for details on how cost can be applied to control which path sessions use Load balancing To distribute the network traffic over multiple DLSw peers in the network Alternately when there are duplicate paths to the destination end system you can configure load balancing DLSw alternates new circuit requests in either a round robin or enhanced load
75. time 100 Router B dlsw local peer 10 2 24 2 cost 1 promiscuous Router C dlsw local peer 10 2 19 5 cost 1 promiscuous Router D dlsw local peer 10 2 20 1 cost 1 promiscuous Cisco IOS Bridging and IBM Networking Configuration Guide 78 11737 02 E EC 327 Configuring Data Link Switching Plus E DLSw Configuration Examples DLSw Peer Cluster Feature Configuration Example Figure 141 shows a DLSw network configured with the DLSw Peer Clusters feature Figure 141 DLSw Peer Cluster Feature ae Za i J i Z J wa J wo P Peer group 1 Peer group 2 17268 Because BP2 is configured as the border peer with the DLSw Peer Clusters feature it does not forward explorers to both MPA and MPB since they are part of the same peer cluster BP2 source bridge ring group 310 dlsw local peer 10 1 1 3 border group 2 promiscuous MPA source bridge ring group 310 dlsw local peer 10 1 1 1 group 2 promiscuous cluster 5 dlsw remote peer 0 tcp 10 1 1 3 MPB source bridge ring group 310 dlsw local peer 10 1 1 2 group 2 promiscuous cluster 5 dlsw remote peer tcp 0 10 1 1 3 MPC dlsw local peer 10 1 1 4 group 2 promiscuous dlsw remote peer tcp 0 10 1 1 3 Cisco IOS Bridging and IBM Networking Configuration Guide BC 328 78 11737 02 _Configuring Data Link Switching Plus DLSw Configuration Examples W DLSW RSVP Bandwidth Reservation Feature Configuration Example Figu
76. ut MAC addresses RIFs or NetBIOS names It also does not describe how to track either capable or preferred DLSw partners for either backup or load balancing purposes The standard does not provide the specifics of media conversion but leaves the details up to the implementation It does not define how to map switch congestion to the flow control for data link control Finally the MIB is documented under a separate RFC DLSw Version 2 Standard IP Multicast In the Version standard a network design requires fully meshed connectivity so that all peers were connect to every other peer This design creates unnecessary broadcast traffic because an explorer propagates to every peer for every broadcast The Version 2 standard is documented in RFC 2166 It includes RFC 1795 and adds the following enhancements IP Multicast page 282 UDP Unicast page 283 Enhanced Peer on Demand Routing Feature page 283 Expedited TCP Connection page 283 Users implement DLSw Version 2 for scalability if they are using multivendor DLSw devices with an IP multicast network DLSw Version 2 requires complex planning because it involves configuration changes across an IP network Multicast service avoids duplication and excessive bandwidth of broadcast traffic because it replicates and propagates messages to its multicast members only as necessary It reduces the amount of network overhead in the following ways Avoids the need to maintain TCP Switch
77. ve to RSRB that addresses several inherent problems that exist in RSRB such as SRB hop count limits SRB s limit is seven Broadcast traffic including SRB explorer frames or NetBIOS name queries Unnecessary traffic acknowledgments and keepalives Data link control timeouts 78 11737 02 Cisco 10S Bridging and IBM Networking Configuration Guide BC 281 Configuring Data Link Switching Plus E Technology Overview DLSw Standard The DLSw standard documented in RFC 1795 defines the switch to switch protocol between DLSw routers The standard also defines a mechanism to terminate data link control connections locally and multiplex the traffic from the data link control connections to a TCP connection The standard always calls for the transport protocol to be TCP and always requires that data link control connections be locally terminated the equivalent of Cisco s local acknowledgment option The standard also requires that the SRB RIF be terminated at the DLSw router The standard describes a means for prioritization and flow control and defines error recovery procedures that ensure data link control connections are appropriately disabled if any part of their associated circuits breaks The DLSw standard does not specify when to establish TCP connections The capabilities exchange allows compliance to the standard but at different levels of support The standard does not specify how to cache learned information abo

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