On 09/28/2018 12:19 AM, Johannes Berg wrote:
On Thu, 2018-09-27 at 08:32 -0700, Ben Greear wrote:
It seems though that if there's some noise or so on the channel you
wouldn't be transmitting, so what kind of "network glitches" might
affect this? AP going away unexpectedly for some time?
I am thinking that if the 'timeout' is 500ms, and the number of probes is 2
(the default values), then it should probe at 0ms, and at 250ms, and then finally
fail at 500ms if nothing was received. In otherwords, X probes, x/timeout apart.
That seems reasonable I guess. Although I'm not sure - perhaps once we
know it failed we *do* want to try a bit quicker again? Otherwise we
have a totally dead period there in the meantime, no?
I don't think the tx path stops just because the mlme decides probes
are timing out, so if AP is really functional, you won't have a dead period.
If it is dead, then the sooner you probe and discover timeout and disconnect,
the sooner you can re-connect to some better AP (assuming one exists). A
false disconnect due to missing a few probes would be disruptive though, and
probing very often in idle situations would use more airtime, so
of course there is a trade-off.
While watching the sniffer, it seems the initial mlme probe happens about
3 seconds after I admin down the AP, and then disconnect is about 1s after
that (I have my timeout set to 1000ms instead of default 500ms, and I have retry
count set to 5 instead of 2.
Did you see that patch I posted? It looks good in the sniffer and logs,
as far as I can tell....
Thanks,
Ben
johannes
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
