Wireless Performance : Too many APs!
Our network engineer wrote a paper a few years ago about the issue of having too many APs in your network and how this actually slows you down. At heart this issue was APs on the same channel seeing each others traffic and backing off thinking there were collisions, when there weren’t. Therefore a busy AP on Channel 6 which was visible to other APs on Channel 6, could cause them all to stop broadcasting if they were all to close.
Well the quick fix for this is to spread your APs over more channels, which was and still is an issue with the 2.4GHz band, but the 5.0GHz band offered lots of space and this problem went away for a while, sort of …………
In our quest for faster and faster wifi, one of the speed improvements we now have at our disposal is wider channels. First it was 40MHz wide, but now its 80 and 160MHz wide channels and guess what, there is little to no space for non-overlapping channels anymore! We have returned to the problem of APs on repeating channels being too close again, which slows your wifi down, again. Which is why you're now hearing about wireless using the 6GHz channel in the near future.
The standards are changing fast and you get different answers depending on who’s website you look at or which country you're in. The bottom line is you still need to plan your design’s carefully if you want reliable wireless networking and not turn everything up to full power and fastest speed options.
One of the best ways to plan is to use survey tools to look at the spread of APs on the same channels and see what power they overlap at. Most good survey tools also give a cross-channel interference report - this is what its all about, how many APs on the same channel can see each other at a signal strength that’s going to be an issue.
Alternatively, Full Control Networks will provide this as a service, telling you what the results mean and what to do about it, not just printing out the reports and leave you staring at something you only vaguely understand.
- Get some real time stats of signal strength, noise and SNR on the wireless network – using a product such a NetAlly AirCheck
- Live survey the current wireless coverage and produce heat maps – with a tool like AirMagnet Survey
- Short form wireless survey and stats in a handheld package – NetAlly EtherScope
- Consider bringing Professional Services in, they'll have their own kit and expert knowledge of the technology to report on what's going on and make recommendations for improved performance