Cisco Catalyst 2960 Series, Configuration Manual

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Enabling Root Guard
Root guard enabled on an interface applies to all the VLANs to which the interface belongs. Do not enable
the root guard on interfaces to be used by the UplinkFast feature. With UplinkFast, the backup interfaces (in
the blocked state) replace the root port in the case of a failure. However, if root guard is also enabled, all the
backup interfaces used by the UplinkFast feature are placed in the root-inconsistent state (blocked) and are
prevented from reaching the forwarding state.
You cannot enable both root guard and loop guard at the same time.
Note
You can enable this feature if your switch is running PVST+, Rapid PVST+, or MSTP.
This procedure is optional.
Follow these steps to enable root guard on the switch.
SUMMARY STEPS
1. enable
2.
configure terminal
3.
interface interface-id
4. spanning-tree guard root
5.
end
DETAILED STEPS
Purpose Command or Action
Enables privileged EXEC mode. Enter your password if
prompted. enable
Example:
Switch>
enable
Step 1
Enters the global configuration mode. configure terminal
Example:
Switch# configure terminal
Step 2
Specifies an interface to configure, and enters interface
configuration mode. interface interface-id
Example:
Switch(config)# interface gigabitethernet1/0/2
Step 3
Enables root guard on the interface. spanning-tree guard root Step 4
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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How to Configure Optional Spanning-Tree Features