Not unless you disable the ssid in the 2.4GHz radio or you disable the 802.11b/g radio on the client. In and LWAPP environment, you can setup a policy to specify what radios are allowed on a wlan ssid. On autonomous ap, you just don't put the ssid under the radio. Certain 3rd party utilities allow you to specify what radio you would like to use when you associate to a radio.
My wish was to force the client to connect to the best access media although both 802.11a and 802.11b/g are active (in order to allow 802.11b/g only clients to connect to the WLAN also)
Well Cisco should consider adding this feature to thier solutions...
Which would bring us to the discussion of what is best, 802.11a or 802.11b/g?
The answer is not simply 802.11b/g. There may be environments with special requirement (for example, high density in a small location like a training room) where 802.11a is your better option because of the bigger number of non overlapping channels.
That said, how about setting up two SSIDs, one for 802.11a, one for 802.11b/g, and then configure both profiles in your clients and have the client prefer one of them prior to the other one?
Undoubtedly i can say that 802.11a is much more prefered from 802.1b/g.
It is much less "crowded" than 802.11b/g, no microwave, blutetooth or cordless phones on the spectrum and it provides 23 overlapping channels while the 802.11b/g provide only 3!
the only disadvantage is that it is forbidden to use in outdoor enviroments (in Israel anyway!)
Setting up 2 SSID's is easy but instruct my laptop to prefer 802.11a on 802.11b/g is very difficult!!!
It is up to the client devices to prefer what band they should use. So in this case, a 3rd party utility can specify what band that device will use when it associates to an ssid. The AP has no control of this, but can be configured to only allow certain bands.
it's not quite true, i think that Cisco can add a feature that will allow you, as a system admin, to configure which band is prefered and then apply it in a way the AP will reject association requests from the client on one band and will replay on the second.
Unfortunately I know your pain. I am forced to use a specific client on my laptop (Thinkvantage) and this particular client software does not allow to put preferences in there either.
However, I can hardly believe there is not some wireless manager client software on the market today that can do the trick.
Tow separate SSID is your way forward, that's for sure. The client software is the challenge ;-)
I have Thinkvantage and there is an option to choose if you want 802.11a, 802.11b or 802.11g. I have Thinkvantage Access Connections 5.02.
Use a different SSID for 802.11a.
Make the 802.11g security more difficult (you need better security there anyway, it's the most likely to be attacked).
Users are generally lazy critters, they'll set up whatever is easiest.