Re: Disabling transmission of beacon frames
Hi Henrique,
On 23/10/16 02:40, Henrique de Moraes Holschuh wrote:
> On Sat, 22 Oct 2016, Jan Bakuwel wrote:
>> Does anyone know if it's possible to disable passive mode on an AP? It
>> is possible to set the SSID to hidden but this does not stop the
>> broadcasts, it just broadcasts frames with a null SSID. Stopping the
>> broadcasts altogether (and as a consequence the client must use active
>> mode, ie. needs to send probes) will result in no EMR when wifi is not
>> in use, in other words AP will only listen not transmit in that case,
>> yet wifi is available when needed.
> 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?
If wifi is in use, we can accept EMR including beacons. Just not when
it's not (for example during the night).
> 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?
> Please ask in the linux-wireless mailinglist at vger.kernel.org.
Thanks for the suggestion, I'll do that.
Jan
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