For the last several weeks, I've had trouble at home with my ath0
interface.  (My house network uses WEP because until very recently, one
of the laptops ran 3.1, which did not have WPA.)  Specifically, I saw
constant

	ath0: device timeout (txq 1)

messages and constant hangs of the interface -- I had to ifconfig it
down/up to restore functionality.  I especially had trouble with longer
tranmissions, though I don't know if it was the number of packets or
the packet size that did it.

Tonight, though, while going through the same problems, I fired up mtr,
just to give me something that would easily monitor the first home.

The problems vanished.  I'm not seeing any timeouts, I'm not seeing any
disconnects, and I can run ttcp at >16M bits/sec to other machines in
the house.  (wlanctl indicates a line speed of 24M bps just now, so
that's reasonable.)

When I killed mtr, the problems -- the timeouts and the interface wedge
-- returned.

One more point...  Last week, I was at Usenix Security, where there was
an open wireless net.  I saw timeout messages but I had no disconnects.

Right now, I'm running 4.99.29, from Aug 15; as I noted a couple of
weeks ago, the problem started with a July 31 kernel but didn't occur
with a Jul 15 kernel.

		--Steve Bellovin, http://www.cs.columbia.edu/~smb