Specifications

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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 14 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
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 in the network. BackboneFast is not
supported on Token Ring VLANs. This feature is supported for use with third-party switches.
The BackboneFast feature is supported only when the switch is running PVST. It is not supported when
the switch is running PVRST.
Beginning in privileged EXEC mode, follow these steps to enable BackboneFast:
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 misconfiguration that causes a loop.
You can enable this feature if your switch is running PVST, PVRST, or MSTP. The PVRST and MSTP
are available only if you have the EI installed on your switch.
Beginning in privileged EXEC mode, follow these steps to enable EtherChannel guard:
To disable the EtherChannel guard feature, use the no spanning-tree etherchannel guard misconfig
global configuration command.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
spanning-tree backbonefast Enable BackboneFast.
Step 3
end Return to privileged EXEC mode.
Step 4
show spanning-tree summary Verify your entries.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
spanning-tree etherchannel guard
misconfig
Enable EtherChannel guard.
Step 3
end Return to privileged EXEC mode.
Step 4
show spanning-tree summary Verify your entries.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.