Re: [STDS-802-Privacy] Proposal on a MAC mediator protocol
Hi Christian,
I would agree that passive scanning to learn the MAC addresses of all
STAs in the vicinity is not practical and would be a huge burden to
devices if it even is possible.
I do disagree however with your statement that devices don't passive
scan in practice. I actually believe the opposite to be true as there
are many times when it is inappropriate to active scan - for example
in large sections of the 5GHz band where the regulatory rules differ
from place to place and a STA may not know if or at what power level
it is permitted to send probe requests. While the strict timing
requirements when roaming from AP to AP in an ESS may require probes,
they are completely unnecessary for the use case where a mobile device has
the screen off in your pocket. In this scenario a well implemented
algorithm of passive scanning only works just fine from a both a power
efficiency and time-to-connect standpoint.
Regards,
-James Lepp (BlackBerry)
On Fri, Nov 7, 2014 at 1:08 PM, Christian Huitema <huitema@xxxxxxxxxxxxx> wrote:
>> While first doing the passive scan before the active scan, the device would learn some of the existing MACs and could easily avoid any it heard.
>
> In practice, devices don't do passive scan. That would require lingering a long time on each channel, with the radio powered on. Not efficient.
>
> -- Christian Huitema
--
James Lepp
Standards Manager
BlackBerry Limited
1001 Farrar Road - Ottawa - Canada