Wireless Access

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Occasional Contributor I
Posts: 6
Registered: ‎03-19-2013

802.11b vs 802.11n air time

Hi,

 

I am using an 620 controller with an 105 AP however i would like to know how the controller manage the air time when having both 802.11b and 802.11n clients connected.

 

From what i know 802.11b uses more air time then 802.11n. when we active bandsteering and perfered-access the controller will manage to change the faster clients to diferent frequency (2.4 or 5GHz) from the slower clients. However, what i really want to know is how that process is done? the controller moves 802.11n clients to a differnete channel leaving 802.11b clients on an another channel? how the controller do to separate the faster clients from the slower clients... since if they all stay together the slower will say the transference rate to the faster clients.

 

Thanks for the help...


best regards

Gonçalo Azevedo

Guru Elite
Posts: 20,770
Registered: ‎03-29-2007

Re: 802.11b vs 802.11n air time

When "fair-access" is enabled, the controller gives 802.11n clients more "tokens" so that they have more time to transmit.  This is not related to band steering.

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor I
Posts: 6
Registered: ‎03-19-2013

Re: 802.11b vs 802.11n air time

And in preferred-access? how the controller do to not penalize the 802.11n clients when there are 802.11b clients connected?

I know that band-steering is not the same that preferred-access. band sterring is the controoler moves the faster clients with 5Ghz capabilities to different channels leving this way less clients in 2.4Ghz...

 

Thanks for the anwser.

 

Best regards

Gonçalo Azevedo

 
Guru Elite
Posts: 20,770
Registered: ‎03-29-2007

Re: 802.11b vs 802.11n air time

[ Edited ]

The controller can decide when it is servicing clients how much airtime it gives to each type of client.  When the QOS  setting is normal, it does not do this.  When it is fair access or preferred, it gives 802.11n clients more airtime by servicing them more frequently, in general.

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor I
Posts: 6
Registered: ‎03-19-2013

Re: 802.11b vs 802.11n air time

so when i have 802.11b clients, my connection in 802.11n will get penalized due to lower rates consecutively more air time from 802.11b clients?

 
Guru Elite
Posts: 20,770
Registered: ‎03-29-2007

Re: 802.11b vs 802.11n air time

Regardless of manufacturer, this is what happens in one form or another.  How MUCH it happens depends on how far away the 802.11b clients are from the access point and how much traffic they have to transmit.



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor I
Posts: 6
Registered: ‎03-19-2013

Re: 802.11b vs 802.11n air time

that is bad news...

 

I was thinking that this problem of slower clients penalize faster clients was solved in more advanced controllers....

 

So if i have 1 client 802.11b and 100 802.11n this b client will penalize the rest of the clients kepping then to transmit at full speed... due to more air time and consequtivly slower rates from the 802.11b clients

Guru Elite
Posts: 20,770
Registered: ‎03-29-2007

Re: 802.11b vs 802.11n air time

Aruba's "fair access" and "preferred access" setting is designed to mitigate that behavior.

 



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

Occasional Contributor I
Posts: 6
Registered: ‎03-19-2013

Re: 802.11b vs 802.11n air time

and how the controller mitigate that behavior in preferred-access?

Guru Elite
Posts: 20,770
Registered: ‎03-29-2007

Re: 802.11b vs 802.11n air time

 

"The controller can decide when it is servicing clients how much airtime it gives to each type of client.  When the QOS  setting is normal, it does not do this.  When it is fair access or preferred, it gives 802.11n clients more airtime by servicing them more frequently, in general."



Colin Joseph
Aruba Customer Engineering

Looking for an Answer? Search the Community Knowledge Base Here: Community Knowledge Base

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