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3.3 Commands for Port Loopback Detection Function
3.3.1 debug loopback-detection
Command: debug loopback-detection
Function: After enabling the loopback detection debug on a port, BEBUG information will
be generated when sending, receiving messages and changing states.
Parameters: None.
Command mode: Admin Mode.
Default: Disabled by default.
Usage Guide: Display the message sending, receiving and state changes with this
command.
Example:
Switch#debug loopback-detection
%Jan 01 03:29:18 2006 Send loopback detection probe packet:dev Ethernet1/10, vlan id
1
%Jan 01 03:29:18 2006 Send loopback detection probe packet:dev Ethernet 1/10, vlan id
2
3.3.2 loopback-detection control
Command: loopback-detection control {shutdown |block| learning}
no loopback-detection control
Function: Enable the function of loopback detection control on a port, the no operation of
this command will disable the function.
Parameters: shutdown set the control method as shutdown, which means to close down
the port if a port loopback is found.
block set the control method as block, which means to block a port by allowing bpdu and
loopback detection messages only if a port loopback is found.
learning disable the control method of learning MAC addresses on the port, not forwarding
traffic and delete the MAC address of the port.
Default: Disable the function of loopback diction control.
Command mode: Port Mode.
Usage Guide: If there is any loopback, the port will not recovery the state of be controlled
after enabling control operation on the port. If the overtime is configured, the ports will
recovery normal state when the overtime is time-out. If the control method is block, the