Wired Intelligent Edge (Campus Switching and Routing)

Q:

How to check/test for a network loop without disabling the ports if a loop is detected.

You can test/check for network loops without disabling any ports by using Loop-Protect and setting the Receiver-Action to "no-disable".

This will allow the switch to check for a loop.  If one is detected, it will add an entry to the event log, but will not disable the port.

You can then view the event log to determine which port(s) a loop was detected.

Use the following commands to enable Loop-Protect without disabling any ports:
  loop-protect all receiver-action no-disable
  loop-protect <port#>      (use "loop-protect all" to enable this on all ports)

Note:  Be sure to configure the receiver-action first, so no ports are disabled once loop-protect is enabled.

If you later decide to take a different action on the port(s), the following receiver-action options are available using Loop-Protect:

   send-disable          Disable the sending port when a loop is detected.  This is the default.
   no-disable              Do not disable the sending port when a loop is detected.
   send-recv-dis         Disable the sending and receiving port when a loop is detected.
 

To disable Loop-Protect, use the following command:

  no loop-protect <port#>     (use "no loop-protect all" to disable this on all ports)