ath0 link up/down frequent

[Kevin Oberman]

> Date: Sat, 22 Aug 2009 13:08:58 -0400
> From: Dan Langille <dan at langille.org>
> Sender: owner-freebsd-mobile at freebsd.org
> 
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> Hash: SHA1
> 
> Hi,
> 
> I get this a lot:
> 
> Aug 22 12:18:40 laptop kernel: ath0: link state changed to DOWN
> Aug 22 12:18:48 laptop kernel: ath0: link state changed to UP
> Aug 22 12:49:49 laptop kernel: ath0: link state changed to DOWN
> Aug 22 12:49:56 laptop kernel: ath0: link state changed to UP
> 
> 
> FreeBSD laptop.example.org 7.2-STABLE FreeBSD 7.2-STABLE #0: Mon May 25
> 20:35:50 EDT 2009     dan at laptop.example.org:/usr/obj/usr/src/sys/LAPTOP
>  amd64
> 
> 
> ath0 at pci0:3:0:0:        class=0x020000 card=0x058a1014 chip=0x1014168c
> rev=0x01 hdr=0x00
>     vendor     = 'Atheros Communications Inc.'
>     device     = 'AR5212 Atheros AR5212 802.11abg wireless'
>     class      = network
>     subclass   = ethernet
> 
> Looking into /var/log/messages:
> 
> 
> Aug 22 10:09:24 laptop kernel: ath0: link state changed to DOWN
> Aug 22 10:09:50 laptop kernel: ath0: link state changed to UP
> Aug 22 10:09:53 laptop dhclient: New IP Address (ath0): 10.0.0.101
> Aug 22 10:09:53 laptop dhclient: New Subnet Mask (ath0): 255.255.255.0
> Aug 22 10:09:53 laptop dhclient: New Broadcast Address (ath0): 10.0.0.255
> Aug 22 10:09:53 laptop dhclient: New Routers (ath0): 10.0.0.1
> Aug 22 10:35:31 laptop kernel: ath0: link state changed to DOWN
> Aug 22 10:35:31 laptop kernel: ath0: link state changed to UP
> 
> 
> FWIW, I'm running wpa as well.
> 
> Anything I should look into?

My standard suggestion, which works for me, is to issue an 'ifconfig
ath0 -bgscan'. Background scanning is not supposed to effect the
association, but it seems to, at least on my system.

The clue was the intervals between the losses were always a bit over to
5 minutes and that is the default bgscan interval. Looks like a bit over
25 minutes between events in your case.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634
Key fingerprint:059B 2DDF 031C 9BA3 14A4  EADA 927D EBB3 987B 3751