Cisco Systems BC-281 manual Scalability, Peer Groups and Border Peers, BC-296

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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).

•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.

Scalability

One 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

•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 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 IOS Bridging and IBM Networking Configuration Guide

BC-296

78-11737-02

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Contents Configuring Data-Link Switching Plus BC-281DLSw Standard DLSw Version 2 StandardIP Multicast BC-282DLSw+ Features Enhanced Peer-on-Demand Routing FeatureUDP Unicast Expedited TCP ConnectionLocal Acknowledgment BC-284BC-285 LLC2 Session without Local AcknowledgmentBC-286 DLSw+ Support for Other SNA Features BC-287Command Purpose Defining a DLSw+ Local Peer for the RouterDefines the DLSw+ local peer Following is a sample dlsw local peer statementTCP Encapsulation Defining a DLSw+ Remote PeerBC-289 TCP/IP with RIF Passthrough Encapsulation FST EncapsulationDefines a remote peer with FST encapsulation BC-290Direct Encapsulation DLSw Lite EncapsulationDefines a remote peer with direct encapsulation Defines a remote peer with DLSw Lite encapsulationToken Ring Mapping DLSw+ to a Local Data-Link ControlBC-292 Ethernet BC-293Associated with this serial interface Enables DLSw+ on an Sdlc interfaceBC-294 Configuring Advanced Features BC-295Peer Groups and Border Peers ScalabilityBC-296 BC-297 Enables peer groups and border peers BC-298Local, remote, and group caches Configures peer-on-demand defaultsBC-299 Displays content of group, local and remote caches NetBIOS Dial-on-Demand RoutingFollowing command enables NetBIOS DDR Explorer FirewallsFollowing command configures the SNA DDR feature UDP Unicast FeatureSNA Dial-on-Demand Routing BC-301Configures a dynamic peer Promiscuous Peer DefaultsLLC1 Circuits Dynamic PeersConfigures promiscuous peer defaults AvailabilityLoad Balancing BC-303Local router BC-304Configures transparent redundancy Backup PeersEthernet Redundancy Addresses on a transparent bridged are mappedModes of Operation Configures a backup peerBC-306 Access Control Network ManagementTraffic Bandwidth and Queueing Management BC-307DLSw+ Bridge Group List Defines a port listBC-308 Filter Lists in the Remote-Peer Command Static PathsStatic Resources Capabilities Exchange BC-309Configuring DLSw+ Timers BC-310BC-311 Following sections provide DLSw+ configuration examples BC-312Router B Router aBC-313 BC-314 DLSw+ with Peer Groups Specified ExampleRouter C BC-315BC-316 FEPRouter D BC-317DLSw+ with Sdlc Multidrop Support Configuration Examples Router EFollowing example, all devices are type PU 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 d2Ring DLSw+ over Frame Relay Configuration ExampleBC-324 DLSw+ over Qllc Configuration Examples Following three examples describe Qllc support for DLSw+Example 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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