Frequent client disassociations reported by hostapd

[Steven Stromer]

Failing to get much useful feedback from the DD-WRT community regarding frequent client disassociations and deauthentications logged by hostapd, I am hoping to get more knowledge from the source.

A thread has existed for months regarding these client disassociations on Atheros-based wireless routing equipment within the DD-WRT forums:
http://www.dd-wrt.com/phpBB2/viewtopic.php?t=171400&postdays=0&postorder=asc&start=0

While the Atheros drivers have been the leading suspect to date for the errors I am receiving (see below), may this be stemming from another source? Might it have something to do with RADIUS authentication? It seems the disassociation always immediately follows the start of an associated RADIUS accounting session. Just a thought. 

Also, the error log specifically states that the deauthentication is due to inactivity. How does the DEAUTH/REMOVE timer function? Might there simply be a bug in how associations are being timestamped? Just another thought.

Forum rumors are that other router software vendors, such as Tomato, have been able to successfully address this bug. Seemingly not so with DD-WRT. Any insights would be VERY much appreciated!


LOG:

# an unsuccessful connection 
Jul 17 21:37:19 router1 daemon.info hostapd: ath0: STA 68:09:27:66:ff:92 IEEE 802.11: authenticated 
Jul 17 21:37:19 router1 daemon.info hostapd: ath0: STA 68:09:27:66:ff:92 IEEE 802.11: associated (aid 6) 
Jul 17 21:37:19 router1 daemon.info hostapd: ath0: STA 68:09:27:66:ff:92 RADIUS: starting accounting session 00000003-00000252 
Jul 17 21:37:35 router1 daemon.info hostapd: ath0: STA 68:09:27:66:ff:92 IEEE 802.11: disassociated 
Jul 17 21:37:36 router1 daemon.info hostapd: ath0: STA 68:09:27:66:ff:92 IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE) 

# successful connection immediately thereafter 
Jul 17 21:37:43 router1 daemon.info hostapd: ath0: STA 68:a8:6d:cc:b4:82 IEEE 802.11: authenticated 
Jul 17 21:37:43 router1 daemon.info hostapd: ath0: STA 68:a8:6d:cc:b4:82 IEEE 802.11: associated (aid 6) 
Jul 17 21:37:43 router1 daemon.info hostapd: ath0: STA 68:a8:6d:cc:b4:82 RADIUS: starting accounting session 00000003-00000253 

# another successful connection immediately thereafter 
Jul 17 21:37:45 router1 daemon.info hostapd: ath0: STA 2c:be:08:ad:46:f6 IEEE 802.11: authenticated 
Jul 17 21:37:45 router1 daemon.info hostapd: ath0: STA 2c:be:08:ad:46:f6 IEEE 802.11: associated (aid 10) 
Jul 17 21:37:45 router1 daemon.info hostapd: ath0: STA 2c:be:08:ad:46:f6 RADIUS: starting accounting session 00000003-00000254 

# an unsuccessful connection, followed by a successful connection of the same client host immediately thereafter 
Jul 17 21:37:57 router1 daemon.info hostapd: ath1: STA d0:e1:40:91:3c:3a IEEE 802.11: authenticated 
Jul 17 21:37:57 router1 daemon.info hostapd: ath1: STA d0:e1:40:91:3c:3a IEEE 802.11: associated (aid 9) 
Jul 17 21:37:57 router1 daemon.info hostapd: ath1: STA d0:e1:40:91:3c:3a RADIUS: starting accounting session 00000008-000000E6 
Jul 17 21:38:11 router1 daemon.info hostapd: ath1: STA d0:e1:40:91:3c:3a IEEE 802.11: disassociated 
Jul 17 21:38:12 router1 daemon.info hostapd: ath1: STA d0:e1:40:91:3c:3a IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE) 
Jul 17 21:38:16 router1 daemon.info hostapd: ath1: STA d0:e1:40:91:3c:3a IEEE 802.11: authenticated 
Jul 17 21:38:16 router1 daemon.info hostapd: ath1: STA d0:e1:40:91:3c:3a IEEE 802.11: associated (aid 9) 
Jul 17 21:38:16 router1 daemon.info hostapd: ath1: STA d0:e1:40:91:3c:3a RADIUS: starting accounting session 00000008-000000E7