DIS-200G Series Gigabit Ethernet Switch CLI Reference Guide
100
21.
Loopback Detection (LBD) Commands
21-1
loopback-detection (Global)
This command is used to enable the loopback detection function globally. Use the
no
form of this
command to disable the function globally.
loopback-detection
no loopback-detection
Parameters
None.
Default
By default, this option is disabled.
Command Mode
Global Configuration Mode.
Command Default Level
Level: 15.
Usage Guideline
The LBD enabled port will send untagged port-based LBD packets out from the port to discover the loop. If
there is a loop occurrence on the path, then the packet being transmitted will loop back to the same port or to
another port located on the same device. When an LBD enabled port detects a loop condition, packet
transmitting and receiving is disabled at the port.
If an LBD disabled port receives an LBD packet and detects that the packet is sent out by the system itself, the
sending port will be blocked.
There are one way to recover an error disabled port. The user can manually recover the port by entering the
shutdown command followed by the no shutdown command for the port.
Example
This example shows how to enable the loopback detection function globally and set the detection mode to port-
based.
Switch# configure terminal
Switch(config)# loopback-detection
Switch(config)#
21-2
loopback-detection (Interface)
This command is used to enable the loopback detection function for an interface. Use the
no
form of
this command to disable the function for an interface.
loopback-detection
no loopback-detection