Verifying the configuration

# View the system logs on devices, for example, Device A.

[DeviceA]
%Feb 24 15:04:29:663 2013 DeviceA LPDT/4/LPDT_LOOPED: Loopback exists on Ten-GigabitEthernet1/0/1.
%Feb 24 15:04:29:667 2013 DeviceA LPDT/4/LPDT_LOOPED: Loopback exists on Ten-GigabitEthernet1/0/2.
%Feb 24 15:04:44:243 2013 DeviceA LPDT/5/LPDT_RECOVERED: Loopback on Ten-GigabitEthernet1/0/1 recovered.
%Feb 24 15:04:44:248 2013 DeviceA LPDT/5/LPDT_RECOVERED: Loopback on Ten-GigabitEthernet1/0/2 recovered.

The output shows the following information:

• Device A detects loops on ports Ten-GigabitEthernet 1/0/1 and Ten-GigabitEthernet 1/0/2 within a loop detection interval.

• Device A automatically shuts down the ports and generates log messages.

# Use the display loopback-detection command to display the loop detection configuration and status on devices, for example, Device A.

[DeviceA] display loopback-detection
Loop detection is enabled.
Loop detection interval is 35 second(s).
No loopback is detected.

The output shows that the device has removed the loops from Ten-GigabitEthernet 1/0/1 and Ten-GigabitEthernet 1/0/2 according to the shutdown action.

# Display the status of Ten-GigabitEthernet 1/0/1 on devices, for example, Device A.

[DeviceA] display interface ten-gigabitethernet 1/0/1
Ten-GigabitEthernet1/0/1 current state: DOWN (Loop detection down)
...

The output shows that Ten-GigabitEthernet 1/0/1 is already shut down by the loop detection module.

# Display the status of Ten-GigabitEthernet 1/0/2 on Device A.

[DeviceA] display interface ten-gigabitethernet 1/0/2
Ten-GigabitEthernet1/0/2 current state: DOWN (Loop detection down)
...

The output shows that Ten-GigabitEthernet 1/0/2 is already shut down by the loop detection module.