Cisco Systems BC-109 manual Controlling Explorer Storms in Redundant Network Topologies

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Tune the SRB Network

Figure 54 Controlling Explorer Storms in Redundant Network Topologies

Station X

Token

Ring 1

Token

Ring 2

Router A

Token

Ring 3

Router B

Token Ring 4

Station Z

S5002

The source-bridgeexplorer-dup-ARE-filtercommand can be used to reduce explorer traffic by filtering explorer frames.

To optimize explorer processing, use one or more of the following commands in global configuration mode:

Command	Purpose
source-bridge explorerq-depth depth	Set the maximum explorer queue
	depth.

source-bridge explorer-dup-ARE-filter	Prevent explorer storms in redundant
	network topologies by filtering
	explorers that have already been
	forwarded once.

source-bridge explorer-maxrate maxrate	Set the maximum byte rate of
	explorers per ring.

You must also disable explorer fast-switching which is, by default, enabled. To disable explorer fast-switching, use the following command in global configuration mode:

Command	Purpose
no source-bridge explorer-fastswitch	Disable explorer fast switching.

To enable explorer fast-switching after it has been disabled, use the following command in global configuration mode:

Command	Purpose
source-bridge explorer-fastswitch	Enable explorer fast switching.

BC-142Bridging and IBM Networking Configuration Guide

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Contents Configuring Source-Route Bridging SRB Configuration Task ListConfigure Source-Route Bridging Configure a Dual-Port BridgeConfigure a Multiport Bridge Using a Virtual Ring Multiple Dual-Port BridgesSource-bridge ring-group ring-group Define a Ring Group in SRB ContextNo source-bridge ring-group ring-group Interface fddi slot/port Configure SRB over FddiEnable SRB and Assign a Ring Group to an Interface Source-bridge route-cache cbusConfigure Fast-Switching SRB over Fddi Configure SRB over Frame RelayEnable the Automatic Spanning-Tree Function Limit the Maximum SRB Hops Configure Bridging of Routed Protocols Enable Use of the RIFConfigure a Static RIF Entry Configure the RIF Timeout IntervalOverview of SR/TLB Following notes and caveats apply to all uses of SR/TLB Enable Translation Compatibility with IBM 8209 Bridges Enable Bridging between Transparent Bridging and SRBDisable Fast-Switched SR/TLB No source-bridge transparent ring-group fastswitchEnable Standard Token Ring LLC2-to-Ethernet LLC2 Conversion Enable Token Ring LLC2-to-Ethernet ConversionEnable 0x80d5 Processing Source-bridge sap-80d5 dsapConfigure NetBIOS Support Specify Timeout and Enable NetBIOS Name Caching Source-bridge proxy-netbios-onlyCreate Static Entries in the NetBIOS Name Cache Configure the NetBIOS Cache Name LengthEnable NetBIOS Proxying Specify Dead-Time Intervals for NetBIOS PacketsNetbios name-cache query-timeout seconds Configure LNM SupportNetbios name-cache recognized-timeout seconds LNM Linking to a Source-Route Bridge on Each Local Ring How a Router Works with LNM LAN Network Manager Monitoring and TranslatingDisable LNM Functionality Disable Automatic Report Path Trace Function Enable Other LRMs to Change Router ParametersEnable LNM Servers Apply a Password to an LNM Reporting LinkChange Reporting Thresholds Monitor LNM Operation Change an LNM Reporting IntervalLnm softerr milliseconds Configure NetBIOS Access Filters Using Station Names Configure NetBIOS Access FiltersSecure the SRB Network Netbios access-list bytes name permit deny offset Configure NetBIOS Access Filters Using a Byte OffsetNetbios access-list host name permit deny pattern Netbios input-access-filter bytes nameNetbios output-access-filter bytes name Configure Administrative Filters for Token Ring TrafficFilter Frames by Protocol Type Filter Source Addresses Filter Frames by Vendor CodeFilter Destination Addresses Access Expression Example Configure Access Expressions Optimize Access ExpressionsAlter Access Lists Used in Access Expressions Tune the SRB NetworkEnable or Disable the Source-Route Fast-Switching Cache Establish the Connection Timeout Interval Enable or Disable the SSEOptimize Explorer Processing Controlling Explorer Storms in Redundant Network Topologies Establish SRB Interoperability with TI MAC Firmware Configure Proxy ExplorersMac-address ieee-address Report Spurious Frame-Copied Errors Monitor and Maintain the SRB NetworkSRB Configuration Examples Source-bridge tcp-queue-max numberDual-Port Source-Route Bridge Configuration Basic SRB with Spanning-Tree Explorers ExampleOptimized Explorer Processing Configuration Example SRB-Only ExampleSRB and Routing Certain Protocols Example Multiport SRB ExampleConfiguration for Router a SRB with Multiple Virtual Ring Groups ExampleConfiguration for Router B SRB over Fddi Configuration ExamplesSRB over Fddi Fast-Switching Example Router aSRB over Frame Relay Configuration Example Frad Using SRB over Frame Relay to Connect to a Cisco RouterConfiguration on Router C Configuration of Router aConfiguration on Router B Adding a Static RIF Cache Entry ExampleAdding a Static RIF Cache Entry for a Two-Hop Path Example SR/TLB for a Simple Network ExampleBC-154Bridging and IBM Networking Configuration Guide SR/TLB with Access Filtering Example Example of a Bit-Swapped AddressNetBIOS Support with a Static NetBIOS Cache Entry Example Specifying a Static EntryWayfarer# show lnm config LNM for a Simple Network ExampleLNM for a More Complex Network Example NetBIOS Access Filters Example Filtering Bridged Token Ring Packets to IBM Machines Example Shows a router connecting four Token Rings Creating Access Filters Example Following access expression would resultAccess Filters Example Fast-Switching ExampleAutonomous Switching Example