[Prism54-devel] Re: basic rates

[Denis Vlasenko]

On Tuesday 27 July 2004 13:29, Margit Schubert-While wrote:
> At 23:18 26.07.2004 +0300, Denis scribeth:
> >Hi Jouni, Luis, Margit, Andreas,
> >
> >I can control advertised basic_rates parameter in hostap
> >(via iwpriv) and acx111 (in code, iwpriv is TODO).
> >I don't know how to control basic_rates for prism54.
> >
> >Now, I am trying to assoc acx111 STA to prism54 AP.
> >
> >In acx111, it is possible to have 1, 2, 5.5, 11 and 22Mbit/s
> >rates in basic_rates set, but not other rates.
> >I've coded all five of them to be included.
> >
> >acx111 can associate with prism54 when prism54
> >is iwconfig'ed to 24M auto, but not with
> >one iwconfig'ed to 54M auto.
>
> Just for info.
> In g-only mode, rates are 6,9,12,18,24,36,48,54
> In mixed b-g, 1,2,5.5,11 are added.

This is bad. If STAs genuinely are not capable
of doing 54Mbit due to hw limitations or if they just don't
advertise 54Mbit in basic_rates set, such STAs would
be rejected by prism54.

I've reread standard. As far as I understood:
Basic_rates set is a set of allowed rates for mgmt
packets. STA must support all basic rates required by AP.

This check is actually done by AP when it receives assoc
request and compares STA basic_rates and its own one.
I suspect many real world APs do not check it
too rigorously, because strictly following standard
may cause interoperability problems with STAs from
other manufacturers.

In my case, acx111 _cannot_ advertise 54MBit in it's
basic_rates. At least it is said so in the docs.

I need to find a way to exclude 54,48,36Mbit
from prism54 AP basic_rates.

After browsing code for a while, I have an impression
that it is simply not known how to do it.
--
vda