Cisco SG300 Help Needed - Broadcast Storm Issue?

I have 20 Aruba Instant IAPs with a HP 2530-48G POE switch to power them. They are connected to a Cisco SG300-52 which is my main MDF switch. I have two other SG300-52 IDF switches connected to the MDF SG300.

What happens is that users start complaining about wireless access problems. I am unable to get access to the web page of the Aruba instant controller. I try pinging the instant controller and the ping times are very high and some time out completely.

In the past, I tracked this down to a room we have with 20 computers in it. When I disconnect the IDF they are connected to, the ping times come back to normal. I then restarted those computers, connected the IDF SG300 back to the rest of the network and things stayed fine.

This has happened twice in the past 8 months. It's happening (sort of) again now. Right now, ping times to my aruba APs aren't as bad as the other two times, but still having some high ping times and some timing out.

On my HP switch, it says that there are "excessive broadcasts detected on port 24". Port 24 is my uplink to my main SG300 MDF switch. It said this error the other two times also.

What I'm wondering is what I can do on the SG300 switches to track down excessive broadcasts? I wish they had an alert like the HP did.

I do see the SG300s under security have "storm control". I have searched and I found how to disable it but want to know from you guys if there is anything I should be aware of before enabling that. Here are my questions:
1) Any reason NOT to enable it on all ports
2) Which of the following types of storm control should I enable:
• Unknown Unicast, Multicast & Broadcast — Click this option if you do not know the type of frame the port receives. This option applies the threshold to all incoming frames.

• Multicast & Broadcast — Click this option so the switch only applies the threshold to multicast and broadcast frames.

• Broadcast Only — Click this option so the switch only applies the threshold to broadcast frames.

Sorry for the long post. Let me know if there is anything else you need to know.

Thanks as always for the help!

About halfway through your post, I identified and automatically assumed this would be a broadcast storm issue. Have you traced your cables to make sure you don't have redundant links on switches that do not have spanning tree? Another possibility is someone is connecting something to network and causing a broadcast storm. I would at the very least configure storm control on your ports that have links to other switches.

The other questions you will have to decide for yourself.

Additionally, I would considering budgeting to replace those SG300 switches. The lack of insight and capabilities they have becomes abundantly clear when issues like this arise and you can't pinpoint root cause and come up with a quick remediation plan.

Thanks for the response. So, are you sure that it just does not have the capability?

I did a chat with support and the person didn't really seem to provide any direction as far as looking for that kind of info. He didn't say it wasn't possible though. You know how it is dealing with tier 1 support though.

Well - it sounds like your SG300 MDF switch is causing broadcast storms and causing your HP switch to shut ports down, or drop frames. You'll need to look at the SG300 to figure out what device is causing the problem.

check the packet counts on the ports, if you see runoff on one or two particular ports, that might narrow down some wiring loops