"mercury" <mercpl@gmail.com> hath wroth:

>I hace recently started to use the HIbernate option when closing down
>my XP SP2 PC. I did this for various reasons, quicker startup and
>shutdown for one. But I have noticed increased instability with my
>wireless connection after a startup from a hibernate shutdown. The
>wireless connection just keeps dropping out. That doesn't happen
>after a normal startup.
>
>Has anyone else experienced this? Is it a known issue?

It seems to be a problem that's equally distributed between the access
points and the clients. I have an HP ze2000 XP laptop with some
Broadcom wireless card that recovers from hibernate just fine with my
WRT54GSv4 (with DD-WRT) in both my home and office. However, the same
laptop has to bludgeoned into cooperation (enable/disable, repair,
etc) at some customers locations. I recently switched from the v3 to
the v4 client drivers on the HP, and recovery was dramatically
improved.

My guess(tm) is that the access points seem to think that they run
things. That's the way 802.11 was written for infrastructure mode.
When I client just disappears (during hibernation), the access point
eventually flushes the MAC address table, clears the WPA encryption
key register, and removes the SSID from the connection table. In
other words, the client is history.

Then, the client magically re-appears as if nothing unusual has
happened. The client assumes that the wireless connection is still
active and proceeds from where it left off. Obviously, this isn't
going to work and the access point is going to reject everything. At
this point, a reasonably intelligent client will recognize the
problem, and re-initiate the entire session starting with the probe
request, encryption key exchange, DHCP request, etc. A stupid client
will just continuously bang on the access point until the user does
something to restart the connection. I've seen both.

I have the same problem with my PDAphone (Verizon XV6700). It has
wi-fi which is really handy. However, the wi-fi section really eats
battery power so various power saving features are used, including
hibernate. Reconnnection is just as slow as an initial connection,
which suggests that it's restarting the connection every time it comes
out of hibernate. Brute force conquers all.

Eventually, we'll have 802.11r (fast roaming) which will allow for
fast connects and disconnects for roaming between multiple access
points. This should (hopefully) have the added beneficial side effect
of also quickly restarting hibernate connections. Meanwhile, it
appears to be a crap shoot.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558