WAP chosen by least load rather than RSSI

[meetarwin]

Hi,

Normally the laptop NIC scans and selects a WAP that has the highest signal strength. I want to make that selection to depend upon the access point loaded the least. For eg. A fully occupied classroom's WAP may be fully loaded when a vacant adjacent classroom's AP is totally idle when the Rx power is just 2-3 db low. Anything I can put in the beacon frames instead of RSSI (Received signal strength indicator)? I land in the WAP and I can see the number of hosts connected. Where could I get the value so that I could use it in a code for comparison? Any pointers of existing codeblocks could help ? I want to use C programming. And I prefer if I could use it for any device viz. Cisco,netgear etc .. and dell, hp, acer any laptop..

[Leo Laohoo]

Normally the laptop NIC scans and selects a WAP that has the highest signal strength.

IDEALLY, laptop NICs (and not wireless APs) decide what APs to join.   Sometimes, (and most of the times) this doesn't work because of default wireless NIC drivers which are badly coded.  

What you may want to do is lower your APs data rates and test the range of the signal.  You lower the data rates to a point that the signal will only cover a small area.  This will force the wireless clients to choose APs in the immediate vicinity.  

[Freerk Terpstra · Accepted solution]

Your client device (more precisely the driver of your wireless NIC) is leading in choosing to which access-point it connects to. There is no way that you are able to change that behavior unless you are having the option to change some settings or even rewrite the driver yourself.

The thing that you want to build does however already exists on the infrastructure side and is being used in VoWLAN deployments. When you enable WMM on your SSID, your access-points are going to include the "Qualtiy of Service Basic Service Set (QBSS)" information element in there beacons. QBSS is an value describing the AP's current load characteristics and contains the current channel utilization (in a value from 1 to 255) and the current client count for that particular radio. If you can configure your clients to use that information in there decision making, there is an chance that they might choose to connect to another access-point. It is very client depended if this is possible and if so what the results are going to be, but you can always give it a try.

If you have too much clients stuck to one access-point in general, you need to change the RF design which means repositioning access-points and/or using different antennas.

[George Stefanick]

To add to the already mentioned comments .. which btw Freerk +5. 

If you have a Cisco WLC you can also use band select and or load balancing on the WLC to get what you need. But again, if you are using sensitive applications these are 2 options you might not want to enable.

[meetarwin]

Hi freerk,

I have a feeling you pretty much hit it . I ll work on what you just gave me . Thanks a lot.