STP

[Roger Richards]

How to find the source of your spanning tree loop(s). What is the best methods or more efficient way to look for them.

[Mohieddin Kharnoub · Accepted solution]

Hi

You can check Topology changes in show span, see the fields:
Topology Change Count: 5 ,
Time Since Last Change : 25 minutes.

If Topology changed a lot, use:
Show Span Detail,
and look port by port, and watch the TC field for top values,
This port may cause a loop in the network, then try to disconnect it, or enable bpdu-filter.

Good Luck !!!