[Madwifi-devel] R: Re: R: Re: Rate selection in monitor mode

[<rob...@cr...>]

Hi,

actually i was meaning something totally different. More precisely i wanted
to know if it is possible to have the built-in rate adaptation in monitor mode.

The funny thing is that you helped me discover a feature of the atheros descriptor
that I didn't knew about. Basically in the the ath descriptors is possible to 
specify four different tx rate each with its own tx attempt. In my case I'm using
click in userspace so I think that I can implement a rate control using the atheros
radio headers.

Bye
R.
 
----- "David Fuste" <df...@ac...> ha scritto:

> Hi Roberto.
> Well, I think it is possible to implement rate control modifying the 
> code of "ath_tx_startraw" in if_ath.c.
> In fact, there is one peace of code inside this call:
> 
> if (ph->try1)
> {
>                 ath_hal_setupxtxdesc(sc->sc_ah, ds,
>                         dot11_to_ratecode(sc, rt, ph->rate1),
> ph->try1, 
> /* series 1 */
>                         dot11_to_ratecode(sc, rt, ph->rate2),
> ph->try2, 
> /* series 2 */
>                         dot11_to_ratecode(sc, rt, ph->rate3), ph->try3
>  
> /* series 3 */
>                         );
> }
> 
> which is for this purpose. The thing is that ph->try1is always 0 in 
> monitor mode.
> But, what do you mean by implementing rate control in user space? do
> you 
> mean via a command line? in this case, I think you are right.
> 
> david
> 
> Roberto Riggio wrote:it seems that it
> > Hi David,
> >
> > thanks for the feedback. Correct me if I'm wrong, but it seems to
> me
> > that there is no way to implement rate control in user space using
> the
> > monitor mode.
> >
> > R.
> >
> > ----- "David FustŽe" <df...@ac...> ha scritto:
> >
> >   
> >> Hi Roberto,
> >> in monitor mode the default retransmission algorithm is 11 
> >> retransmissions at the same rate (I cannot remember which version
> of 
> >> madwifi I use). So, if you specify a rate of 11 Mbps and you
> transmit
> >> a 
> >> frame, if the frame is not acknowledged madwifi will send 11 times
> the
> >>
> >> frame. You can change the rate using the iwconfig command, and the
> 
> >> number of retransmissions by modifying the source code of if_ath.c
> >>
> >> david
> >>
> >> Roberto Riggio wrote:
> >>     
> >>> Hi,
> >>>
> >>> I'm using madwifi (0.9.4) in monitor mode with radiotap header.
> >>>
> >>> 802.11 frames are generated with the click router which also adds
> 
> >>> the radiotap header.
> >>>
> >>> As far as I;ve understood from the madwifi chatroom if i do not
> >>> specify a rate in the descriptor a default rate is used
> >>>       
> >> (6Mbps?!?!).
> >>     
> >>> However it is not clear to me what is happen if i do specify a
> >>>       
> >> rate,
> >>     
> >>> as for example 11 Mbps, and the the first transmission fails. Is
> the
> >>>       
> >>> frame dropped? Is it transmitted again using the rate control
> >>> algorithm?
> >>>
> >>> Thanks 
> >>> R.
> >>>
> >>>
> >>>       
> >>
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> 
> -- 
> ========================================================================
>   0 0 0  David Fusté i Vilella       |    Dept. of Comp. Architecture
>   0 0 0  Ph.D. Student               |    UPC-Campus Nord, D6-001
>   0 0 0  email: df...@ac...    |    C/ Jordi Girona, 1-3
>   U P C  phone: 0034 93 401 67 83    |    08034 Barcelona - SPAIN
>                 www: http://personals.ac.upc.edu/dfuste/
> ========================================================================


-- 
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Roberto Riggio, PhD

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