Subject: Re: ath(4) rate choices for 'bss' in IBSS mode
To: Sam Leffler <>
From: David Young <>
List: tech-net
Date: 09/24/2004 15:20:09
On Fri, Sep 24, 2004 at 12:01:19PM -0700, Sam Leffler wrote:
> On Friday 24 September 2004 11:45 am, David Young wrote:
> > On Thu, Sep 23, 2004 at 05:52:04PM -0700, Sam Leffler wrote:
> > > The bug is actually that ath_tx_start should check for multicast frames
> > > and use a rate appropriate for control frames.
> >
> > FWIW, ieee80211_rssadapt_choose does what Sam is saying.
> I chose to make decisions like this in the driver and not in the rate control 
> code since it would have required passing the packet contents in (or at least 
> a reference to the header).  I believe the handling of 
> control+management+mcast frames is well-enough defined to be done outside 
> rate control.  Separately net80211 is lacking some tunable parameters like a 
> fixed/min rate for data frames and/or all frames.

Seems to me that when the network membership is known, we can make a
smart choice, based on the link adaptation, whether to send multicasts
and mgmt frames at 1, 2, or greater Mbps.  Apart from beacon frames,
sending mgmt frames at low bit rates doesn't seem to be a problem,
but high-throughput multicast apps will suffer.  No?


David Young             OJC Technologies      Urbana, IL * (217) 278-3933