Solved: Autonomous AP setup

alastair27 · ‎07-25-2016

Good morning, I don't do a lot with wireless, and I've inherited a site with a fairly large wireless setup. We use 2.4 only, and there's a lot of old kit out there. This is the radio setup on one of our 1240's

speed basic-5.5 11.0 24.0 48.0
power local cck 11
power local ofdm 5
no preamble-short
channel 2462
station-role root fallback shutdown
rts threshold 2318
no dot11 extension aironet

I get that the lower data rates have been excluded to try and increase throughput, but I don't get why the highest g data rate has been excluded (nor 36)? Also is it normal to specify different cck and ofdm power settings.

Anyone's comments appreciated....

Cheers, Al.

Leo Laohoo · ‎07-26-2016

What can I say? The configuration above is suitable if time was was 1990's.

I would be keen to find out what co-channel interference is currently available.

View solution in original post

mohanak · ‎07-26-2016

You can configure the wireless device to set the data rates automatically to optimize either the range or the throughput. When you enter range for the data rate setting, the wireless device sets the 1 Mbps rate to basic and the other rates to enabled. The range setting allows the access point to extend the coverage area by compromising on the data rate. Therefore, if you have a client that is not able to connect to the access point while other clients can, one reason may be because the client is not within the coverage area of the access point. In such a case using the range option will help in extending the coverage area and the client may be able to connect to the access point. Typically the trade-off is between throughput and range. When the signal degrades (possibly due to distance from the access point,) the rates will renegotiate down in order to maintain the link (but at a lower data rate). Contrast that against a link configured for a higher throughput that will simply drop when the signal degrades enough to no longer sustain a configured high data rate, or roam to another access point with sufficient coverage, if one is available. The balance between the two (throughput vs. range) is one of those design decisions that has to be made based on resources available to the wireless project, type of traffic the users will be passing, service level desired, and as always, the quality of the RF environment.When you enter throughput for the data rate setting, the wireless device sets all data rates to basic (i.e. 12 rates for 2.4 Ghz and 8 rates for 5 GHz).

View solution in original post

Leo Laohoo · ‎07-26-2016

What can I say? The configuration above is suitable if time was was 1990's.

I would be keen to find out what co-channel interference is currently available.

alastair27 · ‎07-26-2016

Ha ha. Spot on Leo!!

My answer since I've been here (and you'd laugh your socks off if I told you what company I'm working at) has mainly been "get some WLAN controllers". Money gets in the way however, and I guess we'll hobble on.....

My other answer was to get stuff on 5, but 5ghz "is banned company-wide"!!!

FWIW, I changed the settings to:

speed basic-5.5 11.0 6.0 12.0 24.0 48.0
power local cck 11
power local ofdm 8.

I figured it's all modern laptops running at least an N card, so if I can get them on g by enabling the lower g rates and upping the power a bit, then I'll disable the b rates....

What do you mean by co-channel interference? Interference between b and g, or interference between this and other APs?

Cheers, Al.

Leo Laohoo · ‎07-27-2016

What do you mean by co-channel interference?

Co-channel interference from other APs, APs that don't belong to you, microwave oven, bluetooth headsets, DECT phone ... the works.

My answer since I've been here (and you'd laugh your socks off if I told you what company I'm working at) has mainly been "get some WLAN controllers".

Turn it on and hide it. If there is a WLC involved then use AP Groups and RF Groups to mask the presence of 5.0 Ghz.

I figured it's all modern laptops running at least an N card

Define "N". There are a number of shonky data sheets out there that says the card supports "802.11 b/g/n".

Just make sure the drivers to the wireless NIC card gets updated regularly. The operative word is "regularly". Getting them updated once adds no value.

alastair27 · ‎07-27-2016

Co-channel interference from other APs, APs that don't belong to you, microwave oven, bluetooth headsets, DECT phone ... the works.

It's a horrible place for wireless. Metal racking, gantries, production-line, industrial ovens, 3rd party ad-hoc wireless networks etc.... Not much I can do about any of it...

Turn it on and hide it. If there is a WLC involved then use AP Groups and RF Groups to mask the presence of 5.0 Ghz.

Need to be careful here, but worth thinking about....

Just make sure the drivers to the wireless NIC card gets updated regularly. The operative word is "regularly". Getting them updated once adds no value.

They do at least keep on top of updates...

Cheers, Al.

Leo Laohoo · ‎07-27-2016

3rd party ad-hoc wireless networks

And these 3rd party ad-hoc are running 802.11b only?

mohanak · ‎07-26-2016

You can configure the wireless device to set the data rates automatically to optimize either the range or the throughput. When you enter range for the data rate setting, the wireless device sets the 1 Mbps rate to basic and the other rates to enabled. The range setting allows the access point to extend the coverage area by compromising on the data rate. Therefore, if you have a client that is not able to connect to the access point while other clients can, one reason may be because the client is not within the coverage area of the access point. In such a case using the range option will help in extending the coverage area and the client may be able to connect to the access point. Typically the trade-off is between throughput and range. When the signal degrades (possibly due to distance from the access point,) the rates will renegotiate down in order to maintain the link (but at a lower data rate). Contrast that against a link configured for a higher throughput that will simply drop when the signal degrades enough to no longer sustain a configured high data rate, or roam to another access point with sufficient coverage, if one is available. The balance between the two (throughput vs. range) is one of those design decisions that has to be made based on resources available to the wireless project, type of traffic the users will be passing, service level desired, and as always, the quality of the RF environment.When you enter throughput for the data rate setting, the wireless device sets all data rates to basic (i.e. 12 rates for 2.4 Ghz and 8 rates for 5 GHz).