Re: Disabling transmission of beacon frames
On Sun, 23 Oct 2016, Jan Bakuwel wrote:
> On 23/10/16 02:40, Henrique de Moraes Holschuh wrote:
> > The AP would have to switch to standard beaconning while *any* station
> > is associated, otherwise it could have nefarious effects on network
> > performance.
>
> Just out of curiosity why is that? I thought beacons were only used
> while AP and client get associated?
No, they're often used when the station is not receiving from the AP,
even when it is already associated.
Also, other receivers (APs and stations) can use them for channel width
management, and for empty channel detection.
> > Also, beacon-less infrasctructure mode CANNOT work on a number of bands
> > where the stations are forced to operate in passive mode (i.e. they
> > cannot issue a probe request to a channel where they did not receive an
> > AP beacon). It is also likely forbidden in any channels where DSS
> > (weather radar detection) must be performed, as this is only performed
> > by APs.
> >
> > So, in theory this would work provided the adapter firmware allows for
> > it in the first place, and it is restricted to channels where clients
> > are allowed to actively probe for APs -- which is information readly
> > available on the regdb (regulatory database). However, I see no way to
> > control this in /sbin/iw for infrastructure mode (but I find iw terribly
> > confusing, so I might have failed to notice it).
>
> I'll need to study that a bit more. My question only concerns the 2.4GHz
> band ... as far as i know DFS only applies to the 5GHZ band, correct?
Well, look at the regulatory database. Some 2.4GHz channels can end up
forced by the kernel into passive mode, depending on several factors.
It really depends on your radio's firmware, what region it is set to,
and what region is your kernel set to.
> > Please ask in the linux-wireless mailinglist at vger.kernel.org.
>
> Thanks for the suggestion, I'll do that.
--
Henrique Holschuh
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