Cisco Systems BC-281 manual DLSw Standard, DLSw Version 2 Standard, IP Multicast, BC-282

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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. 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 about 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

In the Version 1 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.

IP Multicast

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-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 IOS Bridging and IBM Networking Configuration Guide

BC-282

78-11737-02

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Contents Configuring Data-Link Switching Plus BC-281IP Multicast DLSw StandardDLSw Version 2 Standard BC-282UDP Unicast DLSw+ FeaturesEnhanced Peer-on-Demand Routing Feature Expedited TCP ConnectionLocal Acknowledgment BC-284BC-285 LLC2 Session without Local AcknowledgmentBC-286 DLSw+ Support for Other SNA Features BC-287Defines the DLSw+ local peer Command PurposeDefining a DLSw+ Local Peer for the Router Following is a sample dlsw local peer statementBC-289 Defining a DLSw+ Remote PeerTCP Encapsulation Defines a remote peer with FST encapsulation TCP/IP with RIF Passthrough EncapsulationFST Encapsulation BC-290Defines a remote peer with direct encapsulation Direct EncapsulationDLSw Lite Encapsulation Defines a remote peer with DLSw Lite encapsulationBC-292 Mapping DLSw+ to a Local Data-Link ControlToken Ring Ethernet BC-293BC-294 Enables DLSw+ on an Sdlc interfaceAssociated with this serial interface Configuring Advanced Features BC-295BC-296 ScalabilityPeer Groups and Border Peers BC-297 Enables peer groups and border peers BC-298BC-299 Configures peer-on-demand defaultsLocal, remote, and group caches Following command enables NetBIOS DDR Displays content of group, local and remote cachesNetBIOS Dial-on-Demand Routing Explorer FirewallsSNA Dial-on-Demand Routing Following command configures the SNA DDR featureUDP Unicast Feature BC-301LLC1 Circuits Configures a dynamic peerPromiscuous Peer Defaults Dynamic PeersLoad Balancing Configures promiscuous peer defaultsAvailability BC-303Local router BC-304Ethernet Redundancy Configures transparent redundancyBackup Peers Addresses on a transparent bridged are mappedBC-306 Configures a backup peerModes of Operation Traffic Bandwidth and Queueing Management Access ControlNetwork Management BC-307BC-308 Defines a port listDLSw+ Bridge Group List Static Resources Capabilities Exchange Filter Lists in the Remote-Peer CommandStatic Paths BC-309Configuring DLSw+ Timers BC-310BC-311 Following sections provide DLSw+ configuration examples BC-312BC-313 Router aRouter B BC-314 DLSw+ with Peer Groups Specified ExampleRouter C BC-315BC-316 FEPRouter D BC-317Following example, all devices are type PU DLSw+ with Sdlc Multidrop Support Configuration ExamplesRouter E BC-318Following example, all devices are type PU 2.1 Method BC-319BC-320 Hostname Router aBC-321 DLSw+ Translation Between Fddi and Token RingDLSw+ Translation Between Sdlc and Token Ring Media Example BC-322BC-323 Sdlc partner 1000.5aed.1f53 d2 sdlc dlsw d2BC-324 DLSw+ over Frame Relay Configuration ExampleRing Example DLSw+ over Qllc Configuration ExamplesFollowing three examples describe Qllc support for DLSw+ BC-325DLSw+ with RIF Passthrough Configuration Example BC-326DLSw+ with Enhanced Load Balancing Configuration Example BC-327DLSw+ Peer Cluster Feature Configuration Example BC-328DLSWRTR2 BC-329Shows a DLSw+ border peer network configured with DLSw+ Rsvp BC-330DLSw+ with Ethernet Redundancy Configuration Example BC-331DLSw+ with Ethernet Redundancy in a Switched Environment BC-332BC-333 BC-334
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