Enabling Loop Guard - Cisco 6500 Series Software Configuration Manual

Chapter 16 Configuring Optional STP Features

Enabling Loop Guard

Use the set spanning-tree guard command to enable or disable the spanning tree loop guard feature on
a per-port basis.
To enable loop guard globally on the switch, perform this task:
Command
Step 1
Router(config)# spanning-tree loopguard default
Step 2
Router(config)# end
Step 3
Router# show spanning tree interface 4/4 detail
This example shows how to enable loop guard globally:
Router# configure terminal
Enter configuration commands, one per line.
Router(config)# spanning-tree loopguard default
Router(config)# ^Z
Router# show spanning-tree interface fastEthernet 4/4 detail
Port 196 (FastEthernet4/4) of VLAN0010 is forwarding
Port path cost 1000, Port priority 160, Port Identifier 160.196.
Designated root has priority 32768, address 00d0.00b8.140a
Designated bridge has priority 32768, address 00d0.00b8.140a
Designated port id is 160.196, designated path cost 0
Timers:message age 0, forward delay 0, hold 0
Number of transitions to forwarding state:1
The port is in the portfast mode by portfast trunk configuration
Link type is point-to-point by default
Bpdu filter is enabled
Loop guard is enabled by default on the port
BPDU:sent 0, received 0
To enable loop guard on an interface, perform this task:
Command
Step 1
Router(config)# interface {type
{port-channel port_channel_number}
Step 2
Router(config-if)# spanning-tree guard loop
Step 3
Router(config)# end
Step 4
Router# show spanning tree interface 4/4 detail
1. type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet
This example shows how to enable loop guard:
Router# configure terminal
Enter configuration commands, one per line.
Router(config)# interface fastEthernet 4/4
Router(config-if)# spanning-tree guard loop
Router(config-if)# ^Z
78-14099-04
Purpose
Enables loop guard globally on the switch.
Exits configuration mode.
Verifies the configuration impact on a port.
Purpose
1
Selects an interface to configure.
slot/port} |
Configures loop guard.
Exits configuration mode.
Verifies the configuration impact on that port.
Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
End with CNTL/Z.
End with CNTL/Z.
Enabling Loop Guard
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