Specifications

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Catalyst 4500 Se ries S wit ch C is co IO S C om mand R efer ence —Re lease I OS XE 3 .3.0 XO(1 5.1 (1)XO)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
spanning-tree loopguard default
spanning-tree lo opguard default
To enable loop guard as the default on all ports of a specific bridge, use the spanning-tree loopguard
default command. To disable loop guard, use the no form of this command.
spanning-tree loopguard defau lt
no spanning-tree loopguard default
Syntax Description This command has no keywords or arguments.
Defaults Loop guard is disab led.
Command Modes Global configura tion mode
Usage Guidelines Loop guard provides an additional security in the bridge network. Loop guard prevents alternate or root ports
from becoming the designated port because of a failure leading to a unidirectional link.
Loop guard operate s only on por ts th at are c onsidere d point- to-point b y the spanning tree.
Individual loop-guard port confi guration overrides thi s global default.
Examples This example shows how to enable loop guard:
Switch(config)# spanning-tree loopguard default
Switch(config)#
Related Commands Command Description
spanning-tree guard Enables root guard.
show spanning-tree Displays spanning-tree information.