topic Re: Wireless clients bouncing up and down in Wireless

Wireless clients bouncing up and down

tcasartello — Sun, 04 Jul 2021 01:01:05 GMT

We have a Cisco Unified wireless network on our college campus. There's an area of one of our dormitories where people are having an issue where they keep disassociating and reassociating to our wireless network. We have pretty dense coverage in that area (generally get about 5 bars,) and I haven't seen the issue in other areas on our campus. Anything in the area I should look for that could be causing that problem, or could it be a problem with out setup.

Re: Wireless clients bouncing up and down

tcasartello — Fri, 04 Sep 2009 19:16:32 GMT

Just trying to see what kind of problem would cause bouncing on and off.

Re: Wireless clients bouncing up and down

George Stefanick — Sat, 05 Sep 2009 16:23:13 GMT

Hello,

A few things an cause clients to bounce on and off a wireless network.

- Interference is a likely cause of a client to get bounced. Do you have a spectrum card that you can take readings?

- Malfunctioning Clients - I am assuming your client base is a wide mix based on you mentioning that you are a college campus. Is there anything in common with the clients that are getting bounced.

- Is the controller that is handling the access points for this building in the other controller domains?

- Is there a pattern to the disconnects. Does it happen around the same time each day?

Re: Wireless clients bouncing up and down

Leo Laohoo — Mon, 07 Sep 2009 00:15:03 GMT

I'd like to find out what the controllers' error logs.

What are the error messages reported from the clients' side?

Do the clients get Authenticated at all?

Re: Wireless clients bouncing up and down

tcasartello — Wed, 09 Sep 2009 18:19:00 GMT

Every client I've tried over there will do it. Even my own laptop. I did notice this error in that area: Decrypt error occurred for client '00:22:5f:0a:a8:0c' using 'Unknown' key on '802.11b/g' interface of AP 'newdorm-b2-3-4'. This error comes up constantly. We're using an open network in that area so I don't know why I'd getting decrypt errors. All the APs in that whole building are on the same controller, with the same SSID, same mobility group, etc. There IS an AP on the outside of the building in a different mobility group but it has different ssids broadcasting. We do have a "secret" WPA2 802.1x ssid that doesn't broadcast, but no one knows about that but us IT folks.

Re: Wireless clients bouncing up and down

wififofum — Sat, 12 Sep 2009 16:19:50 GMT

What about the possibility there are too many APs to choose from, causing association thrashing? Try turning down the power and/or upping the minimum (Basic) data rate. Are the clients a/b/g? They could also be flapping between radios. Try fixing them to a single spectrum to see if they stabilize at all. I'd also disable all active (deauth-causing) Security Policy features.

Re: Wireless clients bouncing up and down

tcasartello — Sun, 13 Sep 2009 20:16:00 GMT

I'm going to try disabling the A band and upping hte basic data rate. This is of course the one building I don't have heat maps in my WCS (due to lack of floor plans, going to try to aggressively push for our facilities department to give us some) for so it makes it much more difficult to troubleshoot.

Re: Wireless clients bouncing up and down

tcasartello — Mon, 14 Sep 2009 21:40:20 GMT

I did the following which seems to have fixed the association bouncing:

- Disabled the A band on all APs

- Set minimum data rate to 11 MBPs.

- Checked off "Avoid Cisco AP Load"

I want to try to figure out which of these acutally fixed my problem. Any thoughts?

Re: Wireless clients bouncing up and down

tcasartello — Sat, 19 Sep 2009 14:25:03 GMT

Still having major issues with this. Clients are essentially bouncing between various access points and its literally happening every few seconds to 5 minutes. While the earlier steps I took improved the situation for some people, it's still occuring in other places. I never had this problem last year. Over the summer we upgraded to version 6.0 of software on all our controllers. So I don't know why this is occuring now. Is there any other settings I could try?

Re: Wireless clients bouncing up and down

Leo Laohoo — Sat, 19 Sep 2009 23:22:40 GMT

I would like to apologize for not reading your issue properly.

So you are saying the clients in a specific building is experiencing bouncing from one AP to another?

I was once doing a site survey and when I turn around a particular corner of the floor (where the AP is), my Airmagnet would crash and send the OS into the ubiquitous BSoD. After trying on another laptop with the same result, we decided to check the machinery room upstairs (directly above the AP) and we concluded that some kind of electrical interference is causing some kind of "jam" effect.

This dorminotry in question, do they have some kind of legacy-type machineries (mechanical and/or electrical)? Is this affecting the entire dormitory or just a few of the floors?

Re: Wireless clients bouncing up and down

tcasartello — Tue, 22 Sep 2009 18:34:11 GMT

No the one where it's happening the most is actually our newest dorm what was built in 2004.

Re: Wireless clients bouncing up and down

wififofum — Tue, 22 Sep 2009 19:33:08 GMT

What do the RF measurements look like? They must be thrashing for a reason. I take it this code is in use elsewhere where there's no such phenomena?

Co-channel? Can you turn off the BG and see how only A clients behave?

Multipath? Try putting an 1142 in there.

Do you have Cognio (Cisco Spectrum Expert)? Probably a good idea to have anyway.

Re: Wireless clients bouncing up and down

Leo Laohoo — Tue, 22 Sep 2009 23:15:42 GMT

Is this affecting the entire dormitory (built in 2004) or just a few of the floors?

Re: Wireless clients bouncing up and down

ED CARMODY — Fri, 25 Sep 2009 22:04:34 GMT

Get somebody out there with a wireless packet sniffer and a spectrum analyzer... you'll know in 10 minutes what's going on... smells like interference or a bad AP to me.

Re: Wireless clients bouncing up and down

tcasartello — Mon, 19 Oct 2009 23:20:34 GMT

TAC lended us a cognio specturm card. We also did some wireless sniffer capture and they did not see any deauth packets or anything like that. As far as the cognio spectrum card, they said they are seeing some type of interference across all the channels and some strange devices showing up. We're going to try to look into that. The one thing that's weirdest about this, is that when I reboot all the access points, it stablizes all the clients for about a week or so, then the problems start slowly creeping back again.

Re: Wireless clients bouncing up and down

4DigitCCIE — Thu, 22 Oct 2009 14:02:48 GMT

This is pretty much the same issue we are having as a result of CSCta29484. The APs are down long enough to force the client to roam, and up long enough to let them roam back. I didn't see what APs you were using, but ours are 1231s. To confirm, enable telnet/ssh on the AP and issue "show controller dot11 0 | i Beacons" every couple of seconds for about a minute and you'll see "Beacons are disabled" in the output for a period of about 10 seconds at a stretch. Reboot the AP and it's fine for a while. TAC says it will be fixed in the next maint release. -JC

Re: Wireless clients bouncing up and down

tcasartello — Tue, 27 Oct 2009 00:13:57 GMT

Yes tac is starting to point us in that direction too. In areas where this was happening I found a client with that particular power saving mode. I turned WMM off campus wide and rebooted all APs. I'm keeping an eye on a few clients now.

Re: Wireless clients bouncing up and down

tcasartello — Tue, 27 Oct 2009 19:40:39 GMT

Is it normal for beacons on an AP to EVER be shut off? I noticed once while doing that that they shut off for a split second (certainly not 10 seconds)

Re: Wireless clients bouncing up and down

droback — Fri, 30 Oct 2009 13:26:49 GMT

Hey - We at Hamilton College are having EXACTLY the same issue. We run only b/g in the dorms. This just started this semester (upgraded WISms to 6.0.182.0 code in August) - We had been running for 2 years without any issues.

We are working with TAC also and are trying a few different things on these radios. I'll keep you posted.

Re: Wireless clients bouncing up and down

4DigitCCIE — Fri, 30 Oct 2009 13:34:31 GMT

I asked the same question of TAC and they indicated that it is normal to see beacons disabled while the AP was off channel scanning. When the beacons are off due to the bug, multiple iterations of the command show it disabled for a total of 10 seconds or so (at least on our network).