Command Line Interface
4-232
4
9.3.4 (Note 1).
• Port Loopback Detection will not be active if Spanning Tree is disabled on the
switch
.
Example
spanning-tree loopback-detection release-mode
This command configures the release mode for a port that was placed in the
discarding state because a loopback BPDU was received. Use the no form to
restore the default.
Syntax
spanning-tree
loopback-detection release-mode {auto | manual}
no spanning-tree
loopback-detection release-mode
• auto - Allows a port to automatically be released from the discarding state
when the loopback state ends.
• manual - The port can only be released from the discarding state manually.
Default Setting
Auto
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
• If the port is configured for automatic loopback release, then the port will only
be returned to the forwarding state if one of the following conditions is
satisfied:
- The port receives any other BPDU except for it’s own, or;
- The port’s link status changes to link down and then link up again, or;
- The port ceases to receive it’s own BPDUs in a forward delay interval.
• 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.
• When configured for manual release mode, then a link down / up event will not
release the port from the discarding state.
Example
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree loopback-detection
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree loopback-detection release-mode manual
