Excessive broadcast?

[dcheng]

We recently had a situation where an unknown device was plugged into our network causing a massive slowdown. I was not able to save the Wireshark capture since the program became overwhelmed. I was never able to track down the cause. I started testing for the loop back protection feature using a Procurve 4208vl and a mini 3com unmanaged switch.  The Procurve had STP, loop protection and broadcast limit enabled. I had created a loop back on the unmanaged 3com switch by connecting ports 2-3 together. The uplink to the Procurve was saturated immediately. CPU was 100 percent.  I see STP was blocking the uplink port, but the Procurve CPU was still at 100%.  I was still experiencing slow down on my connection to the Procurve. It didn't appear STP or any of these features was able to stop this problem. When I had disabled the STP, then the loop protection did disable the port.  I'm wondering should I implement only loop protection and not STP? I  do not have redundant path. My topology is a center star switch with 5 edge switches.

Any suggestions would be greatly appreciated.

P.S. This thread has been moved from Switches, Hubs, Modems (Legacy ITRC forum) to ProCurve / ProVision-Based.- Hp Forum Moderator

[Vince-Whirlwind]

You would usually use BPDU-protection on your Access ports on your switch. And loopguard. And broadcast rate-limiting.

[dcheng · Accepted solution]

ok. I'll try it out.

Thank you.