Identifying a Bridging Loop
Suspect a loop if you see the following:
■ You capture traffic on a link, and see the same frames multiple times.
■ All users in a bridging domain have connectivity problems at the same
time.
■ There is abnormally high port utilization.
To remedy a loop quickly, shut redundant ports and then enable them one at
a time. Some switches allow debugging of STP (not 3550/2950) to help in
diagnosing problems.