Cisco Systems BC-109 manual Tune the SRB Network, Alter Access Lists Used in Access Expressions

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Tune the SRB Network

The access lists defined in the previous section create the following configuration:

interface tokenring 0

access-expression in ~lsap(202) dmac(701)

!

access-list 202 permit 0x0404 0x0001 ! Permits SNA frames (command or response) access-list 202 permit 0x0004 0x0001 ! Permits SNA Explorers with NULL DSAP

!

!Access list 701 will permit the FEP MAC address

!of 0110.2222.3333

access-list 701 permit 0110.2222.3333

This is a better and simpler access list than the one originally introduced and will probably result in better run-time execution as a result. Therefore, it is best to simplify your access expressions as much as possible before configuring them into the Cisco IOS software.

Note An “access-expression” type filter cannot exist with a “source-bridge” type filter on the same interface. The two types of filters are mutually exclusive.

Alter Access Lists Used in Access Expressions

Because access expressions are composed of access lists, special care must be taken when deleting and adding access lists that are referenced in these access expressions.

If an access list that is referenced in an access expression is deleted, the access expression merely ignores the deleted access list. However, if you want to redefine an access list, you can create a new access list with the appropriate definition and use the same name as the old access list. The newly defined access list replaces the old one of the same name.

For example, if you want to redefine the NetBIOS access list named MIS that was used in the preceding example, you would use the following sequence of configuration commands:

!Replace the NetBIOS access list interface tokenring 0

access-expression in (smac(701) & netbios-host(accept)) no netbios access-list host accept permit CISCO*

Tune the SRB Network

The following sections describe how to configure features that enhance network performance by reducing the number of packets that traverse the backbone network:

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Enable or Disable the Source-RouteFast-Switching Cache

Enable or Disable the Source-RouteAutonomous-Switching Cache

Enable or Disable the SSE

Establish the Connection Timeout Interval

Optimize Explorer Processing

Configure Proxy Explorers

Note In some situations, you might discover that default settings for LLC2 configurations are not acceptable. In such a case, you can configure LLC2 for optimal use. The chapter “Configuring LLC2 and SDLC Parameters” in this publication describes how you can use them to optimize your network performance.

Configuring Source-Route Bridging BC-139

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Contents SRB Configuration Task List Configuring Source-Route BridgingConfigure a Dual-Port Bridge Configure Source-Route BridgingMultiple Dual-Port Bridges Configure a Multiport Bridge Using a Virtual RingSource-bridge ring-group ring-group Define a Ring Group in SRB ContextNo source-bridge ring-group ring-group Source-bridge route-cache cbus Configure SRB over FddiEnable SRB and Assign a Ring Group to an Interface Interface fddi slot/portConfigure SRB over Frame Relay Configure Fast-Switching SRB over FddiEnable the Automatic Spanning-Tree Function Limit the Maximum SRB Hops Enable Use of the RIF Configure Bridging of Routed ProtocolsConfigure the RIF Timeout Interval Configure a Static RIF EntryOverview of SR/TLB Following notes and caveats apply to all uses of SR/TLB No source-bridge transparent ring-group fastswitch Enable Bridging between Transparent Bridging and SRBDisable Fast-Switched SR/TLB Enable Translation Compatibility with IBM 8209 BridgesSource-bridge sap-80d5 dsap Enable Token Ring LLC2-to-Ethernet ConversionEnable 0x80d5 Processing Enable Standard Token Ring LLC2-to-Ethernet LLC2 ConversionConfigure NetBIOS Support Source-bridge proxy-netbios-only Specify Timeout and Enable NetBIOS Name CachingSpecify Dead-Time Intervals for NetBIOS Packets Configure the NetBIOS Cache Name LengthEnable NetBIOS Proxying Create Static Entries in the NetBIOS Name CacheNetbios name-cache query-timeout seconds Configure LNM SupportNetbios name-cache recognized-timeout seconds LNM Linking to a Source-Route Bridge on Each Local Ring LAN Network Manager Monitoring and Translating How a Router Works with LNMDisable LNM Functionality Enable Other LRMs to Change Router Parameters Disable Automatic Report Path Trace FunctionEnable 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 input-access-filter bytes name Configure NetBIOS Access Filters Using a Byte OffsetNetbios access-list host name permit deny pattern Netbios access-list bytes name permit deny offsetNetbios 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 Optimize Access Expressions Configure Access ExpressionsTune the SRB Network Alter Access Lists Used in Access ExpressionsEnable 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 Monitor and Maintain the SRB Network Report Spurious Frame-Copied ErrorsSource-bridge tcp-queue-max number SRB Configuration ExamplesBasic SRB with Spanning-Tree Explorers Example Dual-Port Source-Route Bridge ConfigurationSRB-Only Example Optimized Explorer Processing Configuration ExampleMultiport SRB Example SRB and Routing Certain Protocols ExampleSRB with Multiple Virtual Ring Groups Example Configuration for Router aRouter a SRB over Fddi Configuration ExamplesSRB over Fddi Fast-Switching Example Configuration for Router BFrad Using SRB over Frame Relay to Connect to a Cisco Router SRB over Frame Relay Configuration ExampleAdding a Static RIF Cache Entry Example Configuration of Router aConfiguration on Router B Configuration on Router CSR/TLB for a Simple Network Example Adding a Static RIF Cache Entry for a Two-Hop Path ExampleBC-154Bridging and IBM Networking Configuration Guide Example of a Bit-Swapped Address SR/TLB with Access Filtering ExampleSpecifying a Static Entry NetBIOS Support with a Static NetBIOS Cache Entry ExampleLNM for a Simple Network Example Wayfarer# show lnm configLNM 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 Following access expression would result Creating Access Filters ExampleFast-Switching Example Access Filters ExampleAutonomous Switching Example
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