Channel hopping wireless devices 1

[stussy]

Hi all

We are running 12 access points across our site. From time to time, we have real trouble with devices not wanting to talk to the nearest access point, and instead choosing the point they were last connected to, despite the fact they only get a 20% strength/quality compared with the 100% they could have.

When it was installed the firm put all the ap's out with different channels, and tried a little to make sure the channels were far enough apart not to crossover too much, i.e. channel 4 is near channel 11, channel 9 is near channel 2.

Finally the point I am making - would anyone think I would be better off putting all the access points onto channels 1, 6 and 11 and trying to separate them as best as possible - would this help with devices having to make a very firm decision on what to connect to?

Cheers & hope all have a good weekend (especially us UK'ers with Monday off

 

[bcastner]

You UK'ers should have 14 channels to play with, or at least I though the EU permitted 14. You might consider using EU specific firmware upgrades.

. see if there is an AP density control on the APs. Many of the better ones let you control how strong their output power is used in a dense AP setting; even Linksys permits this for some model routers.

. Signal strength is only part of the equation. A strength of 100% that is noisy is less preferred than a strength of 20% that is clear with little SNR.

. I always found this chart usefull:

http://www.broadbandreports.com/forum/remark,6683522~root=wlan~mode=flat

. There are roughly four independent channels:

http://www.extremetech.com/article2/0,3973,709078,00.asp

And remember that "channels" only make real sense in the 802.11b setting. For 802.11a it does not matter, and for 802.11g it spans several channels and is not sited on one alone. And for 802.1xx with MIMO, you have multiple channels at work and all goes out the window.

I suspect investigating the physical siting of the APs, and the alternative use of antennas on either client workstations, APs, or both, would prove more fruitfull.

 

[stussy]

Thanks for that!

Our devices (nortel 2220's) only allow 11 channels - I will ask re the further channels. I upgraded the firmware only a little while ago, so would have thought they had it covered by then.

That second link is superb. I am lucky in that I have only one dimension to deal with, but that article makes it clear where I could go with the re-numbering.

I have 2 AP's in particular that are causing a problem - I'll try changing the channels on these 2 and see what happens - this is the quickest thing I can try before shifting access points (and cat 5's, and AC sockets, and mounts...)

Cheers

Mike

 

[bcastner]

Note to all, they moved around my link to four channels. Try:

http://www.extremetech.com/article2/0,1558,708876,00.asp

(You have to scroll a bit through the ads to see the Table of Contents for the entire article).