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18-22
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
Chapter 18 Configuring Optional Spanning-Tree Features
Displaying the Spanning-Tree Status
Beginning in privileged EXEC mode, follow these steps to enable loop guard. This procedure is optional.
To globally disable loop guard, use the no spanning-tree loopguard default global configuration
command. You can override the setting of the no spanning-tree loopguard default global configuration
command by using the spanning-tree guard loop interface configuration command.
Displaying the Spanning-Tree Status
To display the spanning-tree status, use one or more of the privileged EXEC commands in
You can clear spanning-tree counters by using the clear spanning-tree [interface interface-id]
privileged EXEC command.
For information about other keywords for the show spanning-tree privileged EXEC command, refer to
the command reference for this release.
Command
Purpose
Step 1
show spanning-tree active
or
show spanning-tree mst
Determine which ports are alternate or root ports.
Step 2
configure terminal
Enter global configuration mode.
Step 3
spanning-tree loopguard default
Enable loop guard.
By default, loop guard is disabled.
Step 4
end
Return to privileged EXEC mode.
Step 5
show running-config
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Table 18-2 Commands for Displaying the Spanning-Tree Status
Command
Purpose
show spanning-tree active
Displays spanning-tree information on active interfaces only.
show spanning-tree detail
Displays a detailed summary of interface information.
show spanning-tree interface interface-id
Displays spanning-tree information for the specified interface.
show spanning-tree mst interface interface-id
Displays MST information for the specified interface.
show spanning-tree summary [totals]
Displays a summary of port states or displays the total lines of the
spanning-tree state section.