Suspected broadcast storm

[ReverentCreature]

All our switches seem to have lights flashing in unison. wifi pings are very slow. Up into the hundreds of milliseconds and dropping out regularly.

Whats the best way to narrow down the offending item. I don't want to just go around ripping cables out and losing track of whats connected to what.

Is there a recommended/proven plan of action?

[andyturpie]

If you are a large site, start pulling out fibre links one at a time to certain parts of the site at the core switch. Once you've isolated at the core - the link lights should start behaving normally again. Then investigate that part of the building. Edited September 20, 2017 by andyturpie

[FN-GM]

What sort of switches are these? Before you start pulling ports etc enable the following

 

1. Spanning Tree on all switches (rapid if possible)

2 . BPDU Guard on access port (not uplinks) - Use in in conjunction with the above. BPDUs are used by spanning tree and this guard will instantly disable the port when it receives an incoming BPDU thus instantly disabling the port causing the loop.