Wireless Channels

[alunmjones]

I have 23 AP's dotted around the school and im trying to figure out a way of getting them to work better, I have been using a Wierless sniffer to see the different channels i have them on, would it be better to have all the AP's to have the same channel say 10 instad of each beeing on its own, with a few repeats a bit appart from each other?

 

they all have the same SSID but do show up with wildley different SNR scores.

 

any help appriciated thanks.

[plexer]

1, 6 & 11 are generally the recommended channels in a non managed wireless environment.

 

Ben

[Abaddon]

The more you have on the same channel, the more interference you wil get. Try to keep adjacent AP's on different channels if you are managing them manually.

[K.C.Leblanc]

Keep to channels 1, 6 & 11.

 

Try to keep nearby APs on different channels.

 

Details here;

 

802.11b WiFi Frequency Channels

 

EDIT: Standalone APs will only work so well in a school environment, you should investigate a managed solution like Aruba, Meru or Ruckus

[alunmjones]

should i set them all to have the same channel? there are no other wierless signals around us, we are set a fair bit away from all the houses

 

Edit: ok, thanks, ill try and plan it out a bit more, re work a few of them, ill keep them seperate, no money to change the system to anything else, got to live with it, might try and get a controler for them at some point

Edited September 16, 2011 by alunmjones

[jamesreedersmith]

No you need to have overlapping APS using different channel eg along a corridor they may go 1, 11, 6, 1, etc.

[plexer]

What make and model are your waps?

 

Ben

[alunmjones]

Netgear WAG102's all the same, just want to see if i can get them running better, they work fine as they are 80-90% of the time, just have a few areas where i can get a signal off a couple but they are all low to average signals

[White_Fi]

Channel selection has always been a popular topic for 2.4GHz WiFi networks, Per-channel allocations in the band are 5MHz wide (enough for a cordless phone etc) but transmissions are much wider. The amount of bandwidth varies on the standard being used (b, g or n), the radios transmission power and other factors. Run up a spectrum analyser and start a big transfer...You'll see.

 

The rule of thumb is to keep APs on 1, 6 and 11. The theory is that at typical transmissions Wifi devices will transmit over bandwidths that range up to 22MHz wide. Using the 1, 6, 11 reuse plan give one channel 25MHz of space between channels.

 

The counter to the 1, 6, 11 design is that a lot of channel space is being wasted. If WiFi devices operate O.K. with only a 20 MHz between APs (or even 18 or 15 MHz), then spacing the channels so far apart could be a waste.

 

If this is the case a 1, 5, 9, 13 channel reuse plan could be used.

 

DO NOT put all your APs on the same channel, you will be creating a massive collision domain and will result in HIGH retransmissions thus reduced throughput. Unless you are running a controller that supports SCA like Meru. But if you do have something like that....Bin it..

Edited September 16, 2011 by White_Fi

[mpe]

Keep to channels 1, 6 & 11.

 

Try to keep nearby APs on different channels.

 

Note that "near" need not relate to physical distance. Also the effective distance between APs can change due to moving objects (including people). If the AP's in question have an "auto" setting for channel then this could work better than explicitally configuring a channel. Also the 1/6/11 applies only if you are using the 2.4G band. If your APs will do both 2.4 and 5G it's probably worth setting any duel band client machines to only use 5G.

[Geoff]

With that amount of APs I would seriously consider moving over to a managed system when time and funding permits. It would avoid exactly this sort of problem (amongst many others).

[snoerre]

With that amount of APs I would seriously consider moving over to a managed system when time and funding permits. It would avoid exactly this sort of problem (amongst many others).

 

Well, he could use two Netgear WFS709TP controller and convert its WAG102 into WAGL102

[gjdb]

Like most people already said, AP`s in the 2.4Ghz range should be configured with channels 1,6 & 11.

You should also consider lowering the Transmitter Power (if this can be configured with these AP`s), if the power is set to high you can get overlapping channels again.

 

A nice freeware tool to do a site survey is Ekahau HeatMapper, it can measure your coverage, channels, ssid`s etc.

So if you have map of your building you can measure exactly the coverage of your individual access points and overall coverage.

 

Also lot of people over here use managed systems, we also have one location with a managed system, but my location has unmanaged Cisco AP`s (40) and we prefer it above our managed system.