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Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
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Chapter16 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
To disable CSUF on an interface, use the no spanning-tree stack-port interface configuration
command. To disable UplinkFast on the switch and all its VLANs, use the no spanning-tree uplinkfast
global configuration command.
Enabling BackboneFast
You can enable BackboneFast to detect indirect link failures and to start the spanning-tree
reconfiguration sooner.
Note If you use BackboneFast, you must enable it on all switches i n th e network. B ackb oneFast is no t
supported on Token Ring VLANs. This feature is supported for use with third-party switche s.
You can enable the BackboneFast feature for rapid PVST+ or for the MSTP, but the feature remains
disabled (inactive) until you change the spanning-tree mode to PVST+.
Beginning in privileged EXEC mode, follow these steps to enable BackboneFast. Thi s p roce dur e i s
optional.
To disable the BackboneFast feature, use the no spanning-tree backbonefast global configuration
command.
Enabling EtherChannel Guard
You can enable EtherChannel guard to detect an EtherChannel misconfiguratio n t ha t c aus es a l oo p.
You can enable this feature if your switch is running PVST+, rapid PVST+, or MST P.
Beginning in privileged EXEC mode, follow these steps to enable EtherChannel guard. This procedure
is optional.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 spanning-tree backbonefast Enable BackboneFast.
Step3 end Return to privileged EXEC mode.
Step4 show spanning-tree summary Verify your entries.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 spanning-tree etherchannel guard
misconfig Enable EtherChannel guard.
Step3 end Return to privileged EXEC mode.
Step4 show spanning-tree summary Verify your entries.
Step5 copy running-config startup-config (Optional) Save your entries in the configuration file.