M> enable
M# configuration
M(config)# line loopback enable
M(config)# interface gi0/1
M(config-if)# line loopback
M(config-if)# end
M# show line loopback configuration
Global Loop Detection Status: Enabled
Port Trunk Link State Loop Detect Recovery Recovery Time
---- ----- ---- ----------- ------------- ----------- --------------
1 --- Up Forwarding Enabled Enabled 60
2 --- Down Forwarding Enabled Enabled 60
3 --- Down Forwarding Enabled Enabled 60
4 --- Down Forwarding Enabled Enabled 60
5 --- Down Forwarding Enabled Enabled 60
6 --- Down Forwarding Enabled Enabled 60
7 --- Down Forwarding Enabled Enabled 60
8 --- Down Forwarding Enabled Enabled 60
9 --- Down Forwarding Disabled Enabled 60
10 --- Down Forwarding Disabled Enabled 60
58
Fig. 4-22 Display of the loop detection and blocking configuration
(line loopback)
(show line loopback configuration)
M> enable
M# show line loopback history
Entry Time(YYYY/MM/DD HH:MM:SS) Event
----- ------------------------- ---------------------------------------------
1 2001/01/01 00:00:33 The loop detected between port 1 and 9
2 2001/01/01 00:01:33 Port 1 auto recovery
M#
Fig. 4-23 Execution example of the loop history display command
(line loopback)
Note:
The loop detection function uses a special frame. When a loop detection
frame is detected on a port on which the Loop detection and blocking func
-
tion is disabled, the sender port is blocked.
For details on loop history messages, refer to Chapter 11, "System Logs."
