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 1 of 2).
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus Technology Overview UDP Unicast 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.
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus Technology Overview Figure 127 LLC2 Session without Local Acknowledgment Router B Router A Token Ring Token Ring WAN 37x5 3x74 S1106a LLC2 session SNA session 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.
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus Technology Overview 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: Note • Experiment with increasing your NetBIOS timers and decreasing your maximum NetBIOS frame size. • Avoid using NetBIOS applications on slow serial lines.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List Figure 129 VDLC Interaction with Higher-Layer Protocols DLSw+ SNASw Data-link users CLSI Ethernet VDLC Data-link controls 51909 Token Ring 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List TCP/IP with RIF Passthrough Encapsulation To configure TCP/IP with RIF Passthrough 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 acces
Configuring Data-Link Switching Plus DLSw+ Configuration Task List Direct Encapsulation To configure direct encapsulation, use the following command in global configuration mode: Command Purpose Router(config)# dlsw remote-peer list-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-nu
Configuring Data-Link Switching Plus 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 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+.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List Ethernet 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+.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List Command Purpose Step 6 Router(config-if)# sdlc xid Specifies an XID value appropriate for the designated SDLC station associated with this serial interface. Step 7 Router(config-if)# sdlc dlsw {sdlc-address | default | partner mac-address [inbound | outbound]} Enables DLSw+ on an SDLC interface. 1. The last byte of the MAC address must be 00.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List • 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 links. Remote LAN-attached devices (physical units) or SDLC-attached devices can access a FEP over an X.25 network without requiring X.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List • 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).
Configuring Data-Link Switching Plus DLSw+ Configuration Task List 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 member peer, but not both because of potential configuration confusion.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List To define peer groups, configure border peers and assign the local peer to a peer cluster, use the following command in global configuration mode: Command Purpose Router(config)# dlsw local-peer [peer-id ip-address] [group group] [border] [cost cost] [cluster cluster-id] [lf size] [keepalive seconds] [passive] [promiscuous] [biu-segment] [init-pacing-window size] [max-pacing-window size] Enables peer groups and border peers.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List 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-
Configuring Data-Link Switching Plus 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] | local | remote] | [mac-address [address] [netbios-names [name] Displays content of group, local and remote caches. Use the group keyword to display the reachability information for the border peer.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List 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.
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List To configure promiscuous peer defaults, use the following command in global configuration mode: Command Purpose Router(config)# dlsw prom-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] [lf size] [lsap-output-list list] [tcp-queue-max size] Configures promiscuous peer defaults.
Configuring Data-Link Switching Plus 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, dlswrtr2 and dlswrtr3 with costs of 4, 3, and 3 respectively, DLSw+ establishes new circuits with only dlswrtr 2 and dlswrtr3.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List Network 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List Figure 130 Mapping Traffic Using Port Lists Token Ring 22 Explorer Token Ring 12 Peer A Token Ring 19 Peer B Port list 2 Token Ring 15 Peer B: Port list 1 Peer C: Port list 2 51860 Peer C Port list 1 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Task List 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.
Configuring Data-Link Switching Plus Verifying DLSw+ Configuring DLSw+ Timers To configure DLSw+ timers, use the following command in global configuration mode: Command 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.
Configuring Data-Link Switching Plus Monitoring and Maintaining the DLSw+ Network Alternately, to verify that DLSw+ is configured, issue the following command in privileged 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.
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples Figure 131 illustrates a DLSw+ configuration with local acknowledgment. Because the RIF is terminated, the ring group numbers do not have to be the same. DLSw+ with Local Acknowledgment—Simple Configuration Router A Token Ring 25 37x5 Ring Group 10 10.2.25.1 Ring Group Router B 12 10.2.5.2 S3241 Figure 131 Token Ring 5 3x74 Router A source-bridge ring-group 10 ! dlsw local-peer peer-id 10.2.25.1 dlsw remote-peer 0 tcp 10.2.5.
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples ! 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 ! 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 loopback 0 ip address 128.207.169.3 255.255.255.
Configuring Data-Link Switching Plus 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) Token Ring 92 Token Ring 500 Router A Mainframe FEP T0 150.150.99.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples dlsw local-peer peer-id 150.150.98.1 group 2 dlsw remote-peer 0 tcp 150.150.100.1 ! interface loopback 0 ip address 150.150.98.1 255.255.255.192 ! 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.
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples clockrate 19200 sdlc role primary sdlc vmac 4000.1234.5600 sdlc address C1 sdlc xid C1 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.
Configuring Data-Link Switching Plus 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 dlsw 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples dlsw bridge-group 5 ! interface loopback 0 ip address 128.207.111.1 255.255.255.0 interface Ethernet 0 no ip address bridge-group 5 ! bridge 5 protocol ieee Router B hostname Router B ! 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 ! interface loopback 0 ip address 128.207.1.145 255.255.255.
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples ! 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 ! interface tokenring 0 no ip address ring-speed 16 source-bridge 500 1 2000 source-bridge spanning ! router eigrp 202 network 150.150.0.0 Router B hostname Router B ! source-bridge ring-group 2000 dlsw local-peer peer-id 150.150.10.1 dlsw remote-peer 0 tcp 150.150.10.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples source-bridge spanning ! 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples 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.
Configuring Data-Link Switching Plus 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples 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 Ring RTR B Token Ring Token Ring RTR C RTR D 51972 RTR A 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 dlsw dlsw dlsw dlsw dlsw local-peer 10.2.19.
Configuring Data-Link Switching Plus 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 X Peer cluster ID 5 MPA BP1 Token Ring BP2 MPB Peer group 1 Peer group 2 17268 Y 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples DLSW+ RSVP Bandwidth Reservation Feature Configuration Example Figure 142 shows a DLSw+ network with the DLSw+ RSVP Bandwidth Reservation feature configured. Figure 142 DLSw+ RSVP Bandwidth Reservation Feature Configured DLSW RTR 1 IP RTR 1 IP RTR 2 DLSW RTR 2 Token Ring 10.2.17.1 10.1.15.2 10.1.16.2 10.2.24.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples DLSw+ RSVP Bandwidth Reservation Feature with Border Peers Configuration Example Figure 143 shows a DLSw+ border peer network configured with DLSw+ RSVP. DLSw+ RSVP Bandwidth Reservation Feature in a Border Peer Network DLSW RTR 1 IP RTR 1 IP RTR 2 DLSW RTR 2 Token Ring Token Ring 10.2.17.1 10.3.15.2 10.3.16.2 10.14.25.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples The following output of the show ip rsvp res command on the DLSWRTR1 verifies that the RSVP reservation was successful: DLSWRTR1#show ip rsvp rese To From 10.2.17.1 10.14.25.2 10.14.25.2 10.2.17.1 Pro DPort Sport Next Hop TCP 2065 11003 10.14.25.
Configuring Data-Link Switching Plus 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 e1 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 dlsw 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 e1 ip address 150.150.2.3 255.255.255.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples Router A dlsw local peer 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.
Configuring Data-Link Switching Plus DLSw+ Configuration Examples Cisco IOS Bridging and IBM Networking Configuration Guide BC-334 78-11737-02
