[Cerowrt-devel] [Make-wifi-fast] what is the right way to do, and rationale, for wifi channel scans?

[Dave Taht]

The discussion on the g+ thread for the channel scan issue got hot and
heavy, here:

https://plus.google.com/u/0/107942175615993706558/posts/WA915Pt4SRN

On Fri, May 13, 2016 at 8:19 PM, Aaron Wood <woody77 at gmail.com> wrote:
> wpa_supplicant?  I've seen some atrocious behavior from wpa_supplicant in
> the past (especially the closed-source versions from some chipset
> companies).
>
> One reason it's likely to be scanning is that it's looking for alternate APs
> for the same SSID, which are "better".
>
> I saw one implementation that would do an all-channel wildcard ssid scan
> (elicting a response from every AP in range), and then would proceed to scan
> every channel for just the ssid it was configured to use (hardcoded in the
> wifi config).  Why it was doing a broadcast for all APs, I don't know.  But
> once you get enough APs in a small enough area, that behavior causes a
> broadcast storm as the probe responses (all at 1Mbps) flood the air, and
> then cause other STAs to miss beacons, and re-scan, and it death-spirals
> from there.
>
> -Aaron
>
> On Fri, May 13, 2016 at 5:19 PM, Dave Taht <dave.taht at gmail.com> wrote:
>>
>> I finally tracked down the source of many of the anomalies I'd
>> seen thus far... channel scans.
>>
>> For the related rant, see:
>>
>> http://blog.cerowrt.org/post/disabling_channel_scans/
>>
>> Still haven't been able to kill it off entirely.
>>
>> --
>> Dave Täht
>> Let's go make home routers and wifi faster! With better software!
>> http://blog.cerowrt.org
>> _______________________________________________
>> Make-wifi-fast mailing list
>> Make-wifi-fast at lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/make-wifi-fast
>
>



-- 
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org