Optimising a Wireless Network

[maniac]

We have quite good hardware on our wireless network here, 41 Cisco 1200 series access points, 1 per classroom, old but funtional. Generally they work quite well, but unfortunitely at the moment they're running WEP security with a stupidly easy to guess wireless key, so obviously I'm looking to change this.

 

Roaming the school with net stumbler I notice there are a lot of areas where I can see a lot of overlapping between access points, so I'm also looking to optimize the coverage as well as improve the security.

 

I already know it's best to use channels 1, 6 and 11 to keep the channels totally seperate, but what about adjusting the signal strength to prevent too much leakage of signal outside the area the AP is serving, does anyone have any experience of doing this? Experimenting with an access point in our offce, i've had it down to 5mw and still got a strong signal at 54MBs from a reasonable distance, but I'm un-sure if this would work in a classroom and still give 30 laptops a decent connection?

 

Also what about disabling the lower connection speeds to prevent clients connecting at too slower rate, would this also work to keep everything working a bit quicker??

 

Any advice, opinions or comments appreciated.

 

Mike.

Edited November 19, 2008 by maniac

[Ric_]

If you purchase a Cisco/BlueSocket management appliance that should work out all your signal strengths for you plus it will do client authentication.

[plexer]

You can also use tools like the wispy to see the coverage available from your wifi network.

 

Ben

[plexer]

Also look at netstumbler too of course.

 

Ben

[plexer]

If you want to do your own site survey PassMark WirelessMon - Wireless 802.11 WiFi monitoring software looks like a nice cheap tool to do it in conjunction with a laptop.

 

Ben

[featured_spectre]

also use a program called inSSIDer as it will tell you the strength of each signal even if windows can't detect it. It also tells you the mac addresses of each router so you know where to place each one for optimal wireless performance.

[SYNACK]

I see that this thread is a bit old but if you are still after some input:

 

but what about adjusting the signal strength to prevent too much leakage of signal outside the area the AP is serving, does anyone have any experience of doing this? Experimenting with an access point in our offce, i've had it down to 5mw and still got a strong signal at 54MBs from a reasonable distance, but I'm un-sure if this would work in a classroom and still give 30 laptops a decent connection?

 

You may actually get a better one, so long as the laptops are still in range to get a good signal there should be less signal bounce to create interfearence and so the connection should be clearer and quicker as it will not have to fight through the reflected signals in the same bandwidth.

 

Also what about disabling the lower connection speeds to prevent clients connecting at too slower rate, would this also work to keep everything working a bit quicker??

 

Any advice, opinions or comments appreciated.

 

I beleive that this would only help if you had 802.11b clients dragging the APs down into compatibility mode. I think that the 11g clients can share nicely as they all use the same standard.

[Ric_]

You can also use tools like the wispy to see the coverage available from your wifi network.

 

Ben

 

Incidentally, Mandy at Westwood Associates (01753 881810) sourced me a nice cheap WiSpy 2.4x recently. Well worth getting one of these if you have any wireless to troubleshoot!

[Jack]

I already know it's best to use channels 1, 6 and 11 to keep the channels totally seperate

 

These are the only three non-overlapping channels, so yes, it is best to use them and best to make sure that you don't have any overlaps you do have between APs are on different channels.

 

what about adjusting the signal strength to prevent too much leakage of signal outside the area the AP is serving, does anyone have any experience of doing this?

 

Definitely worth turning down the power to the minimum needed, but it might take some trial and error before you find the optimum.

 

Also what about disabling the lower connection speeds to prevent clients connecting at too slower rate, would this also work to keep everything working a bit quicker??

 

Shouldn't make any difference, but if you've got that many clients it might be worth leaving the slower speeds enabled, especially if you are planning on lowering the power.