Cisco Catalyst 2950 - Enabling Etherchannel Guard

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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 15 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
Beginning in privileged EXEC mode, follow these steps to enable BackboneFast. This procedure is
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 misconfiguration if your switch is
running PVST+, rapid PVST+, or MSTP.
Beginning in privileged EXEC mode, follow these steps to enable EtherChannel guard. This procedure
is optional.
To disable the EtherChannel guard feature, use the no spanning-tree etherchannel guard misconfig
global configuration command.
You can use the show interfaces status err-disabled privileged EXEC command to show which switch
ports are disabled because of an EtherChannel misconfiguration. On the remote device, you can enter
the show etherchannel summary privileged EXEC command to verify the EtherChannel configuration.
After the configuration is corrected, enter the shutdown and no shutdown interface configuration
commands on the port-channel interfaces that were misconfigured.
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.