Subject: Re: ath0 carrier coming and going
To: Steven M. Bellovin <>
From: Alicia da Conceicao <>
List: current-users
Date: 12/24/2004 07:31:30
> I'm running a very fresh -current on a Thinkpad T42 with an 802.11a/b/g 
> card.  I also run ifwatchd, and I see that carrier on the ath interface 
> is dropped/restored about once per minute.  Why is that?  At the 
> moment, it's the active interface I'm using to get out to the world.

Dear Steven:

I previously had the exact same problem.  Since I always run a current
snapshot, typically no more than a few weeks old, at first I assumed
that it was fixed in current, since it stated working fine after that.
I then mistakening closed my NetBSD Problem Report #25296.

Then I discovered much later on that one of my employees changed the
Wi/Fi access point from an SMC to a DLink.  When I took the SMC access
point home and tested from there, the problem with the carrier dropping
every few minutes occured again, even when I was only less than 1 meter
from it, and other Wi/Fi devices using the same access point never lost
their carrier.  And yet at work with the DLink access point, the carrier
never ever drops.  The carry also never drops when I run WinXP on my
dual-boot (NetBSD+WinXP) laptop and use the same Atheros card and same
SMC access point.

I do not know why the ath driver causes the carry to periodically drop
every few minutes, on some access points but not others, even when those
access points use the same WEP key, channel, and SSID.  And I apologize
for closing Problem Report #25296, when this bug with the ath driver on
NetBSD has not yet been fixed.