band select white paper, technical doc?

[Gustavo Novais]

Hi all,

I've found a few info on how to configure the bandselect feature, I think I have an idea how it would work, but I was looking for some literature/documentation that would explain how does BandSelect work with some detail?

Can anybody point to some documentation? Config guides, etc, I've already brwsed through but they just say how to configure and what it achieves. It doesn't specify how does it get clients to be steered to the 5GHz band.

Thanks

Gustavo

[Leo Laohoo]

Evaluating Key Architectural and Operational WLAN Strategies in the Era of 802.11n
www.cisco.com/en/US/solutions/collateral/ns340/ns394/ns348/ns767/farpointWLAN_strategies_wp.pdf

Don't forget to rate useful posts.  Thanks.

[Gustavo Novais]

Hello, thanks for your prompt reply.

Unfortunately, I had found this document and it explains the purpose of the feature (that we all now by now) but it doesn't explain how do they achieve that.

My consideration is mostly the technology itself. Does it change beacons/probe replies in any way? How does it influence a client? Is it anything similar to AP load balancing of clients?

anyway I think I'll have to spend a bit of time labbing it up.

Thanks

Gustavo

[George Stefanick]

There is little info on this ... I do know the controller steers clients by ignoring the probe request from clients.. So if a client has a and g enabled, the controller detects a strong signal with a and will ignore the g probes... steering it to a...

[Gustavo Novais]

Hi George,

That's pretty much what I also could gather.

Thanks for replying.

Gustavo

[George Stefanick]

btw ... Ap load balancing doesnt work only because some clients ignore reason code 17 ...

[Mazzola68]

Hi George

what is a reason code 17 ?

Thanks in advance

[Gustavo Novais]

Hi, status code 17 is actually the reason (status code) an AP can give to reject an association request.

If you check table 7-23 on 802.11-2007 document

Association denied because AP is unable to handle additional associated STAs.

When a client tries to associate, the AP can refuse its association request (a few times), hoping that the client will choose another AP to associate to.

Usually they would do that after they have reached a capacity threshold that was admin configured. Obviously they will not not refuse EVERY association request (after the third one, they'll let the client in), or else they'd be denying service.

Gustavo

[Mazzola68]

Thanks Gustavo

Where I can found other information about  check table 7-23 on 802.11-2007 document ?

Thanks.

[Gustavo Novais]

Just go here:

http://standards.ieee.org/getieee802/802.11.html

THIS is heavy reading. IETF RFC's are lightweight compared to this.

[Mazzola68]

Thanks for all Gustavo and have a good day.