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Q: Problem with intermittent disconnect with Linksys router

Last response: in Wireless Networking
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Anonymous
a b D Laptop
a b F Wireless
July 3, 2004 4:13:20 PM

Archived from groups: alt.internet.wireless (More info?)

Hi,

I'm sorry if this problem has been addressed before, but thus far I
don't one described quite like this...

I recently bought a Linksys BEFW11S4 router for wireless use with one
remote laptop. When I fire up the laptop, it sees the wireless network
and can connect, no problem. Things work fine for about 45 minutes, at
which point the laptop is disconnnected. Subsequently, the laptop will
report that it is connected, then disconnect in about 3 seconds,
re-connect 3 seconds later, and repeat.

The 45 minute time point is not exact, but it is roughly consistent
each time I use the laptop.

Like I said, the router is a Linksys BEFW11S4. I just upgraded to
firmware version 1.50.10.
The laptop is a Dell Lattitude C840 running WinXP. The laptop card is
a Truemobile 1150 Mini PCI internal card. I am using WPA/TKIP
encryption with MAC filtering. I use WZC.

If have omitted any information that is needed to a proper diagnosis,
let me know.

On another point: what exactly is 'group key renewal?' Is this value
part of the problem?

TIA,
-Mark
Anonymous
a b D Laptop
a b F Wireless
July 3, 2004 4:13:21 PM

Archived from groups: alt.internet.wireless (More info?)

On Sat, 03 Jul 2004 12:13:20 -0400, sempre <> wrote:

>I recently bought a Linksys BEFW11S4 router for wireless use with one
>remote laptop. When I fire up the laptop, it sees the wireless network
>and can connect, no problem. Things work fine for about 45 minutes, at
>which point the laptop is disconnnected. Subsequently, the laptop will
>report that it is connected, then disconnect in about 3 seconds,
>re-connect 3 seconds later, and repeat.

The laptop is probably going into some kind of power save mode. The
wireless card probably has some kind of power managment function or
"power save" settings in its configurations.

>The 45 minute time point is not exact, but it is roughly consistent
>each time I use the laptop.

Are you using the laptop during the 45 minutes or is it sitting idle?
If you're using it, then it's probably not the power save function.
My 2nd guess would be that 802.1x authentication is getting in the
way. Windoze XP seems to have a problem re-associating itself after a
disconnect if 802.1x is enabled. I've seen this on some (not all)
systems. Disable if you're not using it.

MS has a service pack that is suppose to fix re-connection problems:
http://support.microsoft.com/default.aspx?scid=kb;EN-US;826942
I'm not convinced that it's really fixed. Read through the symptoms
and see if any sound familiar.

>Like I said, the router is a Linksys BEFW11S4. I just upgraded to
>firmware version 1.50.10.

Did you reset the router to defaults after the flash upgrade?
Forgetting to do that has bitten me a few times where I assume that
all the setting are kosher, but ended up with garbage left over from
the previous setup.

>The laptop is a Dell Lattitude C840 running WinXP. The laptop card is
>a Truemobile 1150 Mini PCI internal card. I am using WPA/TKIP
>encryption with MAC filtering. I use WZC.
>
>If have omitted any information that is needed to a proper diagnosis,
>let me know.

>On another point: what exactly is 'group key renewal?' Is this value
>part of the problem?

It's part of WPA encryption. It's the interval at which a new global
encryption key hash is generated and sent. The default is 3600
seconds (1hr). It's not really a "group key" but is more commonly
refered to as a "global key" renewal.

http://support.microsoft.com/default.aspx?scid=kb;en-us;815485
"With 802.1x, the rekeying of unicast encryption keys is optional.
Additionally, 802.11 and 802.1x provide no mechanism to change the
global encryption key used for multicast and broadcast traffic. With
WPA, rekeying of both unicast and global encryption keys is required.
For the unicast encryption key, the Temporal Key Integrity Protocol
(TKIP) changes the key for every frame, and the change is synchronized
between the wireless client and the wireless access point (AP). For
the global encryption key, WPA includes a facility for the wireless AP
to advertise the changed key to the connected wireless clients."


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