550 Spanning Tree Commands

spanning-tree guard

The spanning-tree guard command selects whether loop guard or root guard
is enabled on an interface. If neither is enabled, the port operates in
accordance with the multiple spanning tree protocol. Use the “no” form of
this command to disable loop guard or root guard on the interface.
Syntax
spanning-tree guard {root | loop | none}
root
— Enables root guard.
loop
— Enables loop guard
none
— Disables root and loop guard.
Default Configuration
Neither root nor loop guard is enabled.
Command Mode
Interface Configuration (Ethernet, Port Channel) mode.
User Guidelines
There are no user guidelines for this command.
Example
The following example disables spanning-tree guard functionality on ethernet
interface 4/g1.
console#config
console(config)#interface ethernet 4/g1
console(config-if-4/g1)#spanning-tree guard none

spanning-tree loopguard

Use the spanning-tree loopguard command to enable loop guard on all ports.
Use the “no” form of this command to disable loop guard on all ports.