Chapter 17
| Spanning Tree Commands
– 428 –
spanning-tree
loopback-detection
This command enables the detection and response to Spanning Tree
loopback BPDU packets on the port. Use the
no
form to disable this feature.
Syntax
[
no
]
spanning-tree loopback-detection
Default Setting
Enabled
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
◆
If Port Loopback Detection is not enabled and a port receives it’s own
BPDU, then the port will drop the loopback BPDU according to IEEE
Standard 802.1W-2001 9.3.4 (Note 1).
◆
Port Loopback Detection will not be active if Spanning Tree is disabled on
the switch.
Example
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree loopback-detection
spanning-tree
loopback-detection
action
This command configures the response for loopback detection to shut down
the interface. Use the
no
form to restore the default.
Syntax
spanning-tree loopback-detection action
{
block
|
shutdown
duration
}
no spanning-tree loopback-detection action
shutdown
- Shuts down the interface.
duration
- The duration to shut down the interface.
(Range: 60-86400 seconds)
Default Setting
shutdown, 60 seconds
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
◆
If an interface is shut down by this command, and the release mode is set
to “auto” with the
spanning-tree loopback-detection release-mode
