Edge-Core ECS4810-12M Layer 2, Management Manual

Page: 909 / 1236

C
HAPTER
34
| Spanning Tree Commands
– 909 –
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.
S
YNTAX
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.
D
EFAULT
S
ETTING
auto
C
OMMAND
M
ODE
Interface Configuration (Ethernet, Port Channel)
C
OMMAND
U
SAGE
◆
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. It can only be
released using the spanning-tree loopback-detection release command.
E
XAMPLE
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree loopback-detection release-mode manual
Console(config-if)#