Lost EAPOL packets while connection

Thomas Graf post at thomas-graf.de
Mon Jan 9 05:10:51 PST 2017


I'm still fighting against problems with connection establishment to an 
access point.
I upgraded to the latest Kernel (4.9.2) and to the wpa-supplicant to git 
version d1ea80361b0d4fa4beda6f3c2fbd335fef59b42d.

I tracked down the issue to lost EAPOL packets. I'm using the ath9k 
driver which is repeating packets 10 times. The problem is when they are 
The typical time of retrying is about 2msec. On a heavily loaded 
channels I often see lost EAPOL packets.

On a previous proprietary platform the usual way was to flag EAPOL 
packets for more retries and the wpa-supplicant was notified of 
unsuccessful transmission.

On linux with wpa_supplicant I only see long timeouts after lost EAPOL 
frames. I suppose in mac80211 there should be some extended handling for 
EAPOL frames.
Always waiting for the timeout and then restarting from the beginning is 
not a good solution.

On a channel on 2.4Ghz I see a typical channel usage of 50% or more. 
That causes the authentication to fail of lost packets of about 10% in 
my environment.


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