Help! My network is sick.

Products PMP
1

I hope someone out there can point me in the right direction. Recently I’ve noticed something disturbing on my network ( roughly 7 Gemini backhaul links, 7 CMMs, 30 900MHz APs and 600 SMs).

Ping time to my APs generally run 10ms. Something is happening though that causes all of my AP ping times to jump to 300-400ms and sometimes time out. The event usually lasts anywhere from 20 seconds to 2 minutes. When this occurs, ping times to all my other devices (CMM, BH) remain the same. All devices have a 172.16.x.x/16 address.

Anyone have any ideas? Thanks in advance.

2

It’s odd that it’s all of the AP’s, however it may narrow down the search. I assume the AP’s are all on the same block of IP’s? i.e. 172.16.x.1/16? This may indicate a problem with one AP flooding that block with garbage and all the AP’s answering.

The very first thing I would do is do a hard power cycle on every CMM and AP. If the problem goes away you can just chalk it up to a confused AP or CMM. If it returns you can use a packet sniffer and have it watch the IP range of the AP’s.

I’d start looking at each AP’s Ethernet Stats, Bridge Table (BridgeFullErr), Socket Stats, NI Buf Stat errors.

Here is what healthy Ethernet Stats, Socket Stats, and NU Buf Stats look like:




3

I have seen this but its usually traffic related. The AP’s that are goofing up, how many subscribers do you have on them? It could be a small network storm, but I would most def. recommend putting a traffic sniffer on your network and see whats happens during that spike.

4

Are you using version 7 or version 8 software on these AP’s?

5

Hello Everyone,

Thanks for the help. It ended up being an abundance of ARP traffic.

I’m in the process of moving my network from SM NAT to SM bridge and having customers log in via PPPoE. I accidentally left ARP open and ended up flooding the network.

Jerry,

Thanks so much for your help. I realized just how valuable you are to this community when your reply to this post led me in my troubleshooting to several other posts you’ve made on this site. Anytime you find yourself in Houston, I’ll buy first round.