APs in Repeater Mode

[barryfowles]

Hi all,

Has anyone had problems when using repeater mode with AP1200s. We are having connectivity issues with the repeater AP. Looking at the logs on the repeater AP there seems to be a lot of authentication/deauthentications going on caused by too many missed beacons. Replacing the repeater with a WGB works fine.

Thanks for any help.

Barry

[jcornford]

Firstly, unless I missed something, how could you have replaced the repeater AP with a WGB? They don't perform the same function. An AP as a repeater just serves to increase the range of a link by adding another RF hop. A WGB provides a link from wired clients back to a root AP/bridge. Maybe you had the WGB connected to the repeater and from there to the Root AP/Bridge?

Regardless, too many missed beacons would normally indicate some RF interference of some kind, or a weak signal. If you reassociate the repeater, what kind of signal strength does it have to the Root AP/bridge? Look at the signal levels from both sides and maybe perform a carrier test. What you might have is a mis-configuration of the antennas (power/diversity settings), which might give you a poor signal. If the WGB is in the same physical spot as the repeater was, the repeater ought to work if:

A. The antennas power/diversity setting are correct (maybe the WGB is set to 100mw and the repeater AP to 50mw or something?).

B. You aren't running into a bug (some versions have lots, use the latest of whatever(IOS/VxWorks)).

C. The repeater AP isn't faulty.

[barryfowles]

The WGB was originally connected to the repeater AP. As the repeater wasn't reliably connecting to the root AP it was replaced with the WGB connecting directly to the root. This worked fine with no connectivity problems. The same antenna and power settings were used on both AP and WGB. The AP was upgraded to the latest IOS with no difference. All clients associating directly to the root have no connectivity problems.

We have now tried AP1200s as repeaters in different locations with the same poor results when repeater mode is employed. Hence my original question, has anyone noticed poor connectivity with Cisco APs in repeater mode?

[jcornford]

Ok. Sounds like you've done the normal troubleshooting steps. The only other thing I can think you might want to try is the link test I suggested. Reason is that when an AP is in repeater mode it's going to get more errors on the radio interface due to the nature of its operation (relaying between two "hidden" RF nodes). This might cause enough beacons to be missed, and result in the phenomena you’re seeing. You might find switching channels helps, but you probably already tried that. If you do see lots of retries on the link test results, perhaps you should try increasing the retry timers to combat the problem?

If none of that helps, maybe you should log a TAC case?

[dewman03]

I am in the same boat my friend.

I have a root Ap and a Repeater Ap

The Repeater Ap has a tendicency to reauthenticate to the Root Ap alot, and fills my ACS logs with successful logins. This happens alot when a client connects to the repeater, this makes the repeater attempt to reauthenticate to the Root, over and over again.

I am using diversity antennas at each end and have the power cranked to 100 mw

I have moved my Root Ap closer to the repeater, and have positied the antenna for better coverage.

Now I noticed that the Repeater reauthenticates to the Root once, when a client connects to the repeater.

One Reauthentication is OK, better than filling my logs.

I will monitor behavor and report back in this Post, so maby we both can come to a solution.

[barryfowles]

We've sorted some of the connectivity issues by disabling the "reliable multicast to workgroup bridges" setting. I had enabled this thinking that because we are using workgroup bridges to connect fixed PCs to the WLAN this would improve performance. However, I found a note saying don't use this setting if you don't need to as it puts a high load on the radio cell. As we are using several daisy-chained repeaters with a number of workgroup bridges, throughput is an issue.

Ping responses have improved but there is still a lot of disassociation/reassociation going on.

[avanuden1]

Hi Barry,

I had exact the same problems as you have. I worked for more then a year without any problems and then these troubles started. The way I could solve it was to change the radio channel from 7 to 1. First I did a check with the carrier busy test and then I choose the one with 0% busy. Changed both AP to this frequency and that did the job.

Hope this helps you too.

Cheers,

Arthur

[dewman03]

Hi Guys,

i have also tried changing the channel to try and decrease the amount of reauths that the repeater performs. I use 1,6 and 11, with 6 and 11 having slightly less reauths than 1 did. Like I said earlier, I moved the root closer to the repeater and noticed the biggest drop in reauths bu the repeater.

I also looked at signal strength and signal qualtiy on the advanced radio page

Both these are dBm values and I dont know what is acceptable ranges for each.