2009-02-04 23:19:21

by Luis R. Rodriguez

[permalink] [raw]
Subject: Re: [ath9k-devel] Setting 11n MCS TX bitrate

On Wed, Feb 04, 2009 at 02:51:13PM -0800, Kishore Ramachandran wrote:
> "Not yet, but please feel free to give a shot at hacking it up. It would require
> a new cfg80211 command but keep in mind the way I believe we want this is to
> use the 802.11 MLME SAP interface for this."
>
> I thought as much to start looking at the iw source but thought would check with you guys first. Would the implementation be similar to the "set channel" and/or the "set frequency" commands? Is there is another function using the 802.11 MLME SAP interface that I can use as a guideline?

Well in general I was talking about IEEE-802.11 section 10.3 stuff.
In cfg80211/nl80211 we don't want to allow things like "set essid"
as iwconfig has, instead we want to break things down a bit more,
which can really help debugging. The MLME SAP already has some
decent layout of commands/responses but after a quick glance
I do not see anything for setting a static rate. May want to review
that a bit before implementing set rate though. Just remember
post early and review early. If you have an idea of how you want
to do it let us know to get feedback.

Luis


2009-02-05 09:29:58

by Jouni Malinen

[permalink] [raw]
Subject: Re: [ath9k-devel] Setting 11n MCS TX bitrate

On Wed, Feb 04, 2009 at 03:18:40PM -0800, Luis R. Rodriguez wrote:
> Well in general I was talking about IEEE-802.11 section 10.3 stuff.
> In cfg80211/nl80211 we don't want to allow things like "set essid"
> as iwconfig has, instead we want to break things down a bit more,
> which can really help debugging. The MLME SAP already has some
> decent layout of commands/responses but after a quick glance
> I do not see anything for setting a static rate. May want to review
> that a bit before implementing set rate though. Just remember
> post early and review early. If you have an idea of how you want
> to do it let us know to get feedback.

TX rate control is outside the scope of IEEE Std 802.11-2007 (see 9.6
Multirate support) and as such, there is no MLME SAP (or any other)
primitives for this type of functionality defined in the standard. The
parameters are passed into PHY through the PHY-SAP interface in TXVECTOR
(e.g., DATARATE and MCS). How the MAC sublayer decides how to set these
parameters or even things like how to control the decision process are
very much out of scope.

--
Jouni Malinen PGP id EFC895FA