Random Client Disconnects

[ben.bass0]

I am having a problem with my company's wireless

environment where clients are randomly losing their network connection.  A client can be working normally and all of a sudden they will lose all network connectivity.  There is just the standard yellow exclamation point which indicates no Internet connectivity.

Looking further into this, the client still shows as being associated with the AP and still has an IP address assigned.  At this point you can't ping anything, not even on the local network or the gateway.  A packet capture just shows outgoing arp requests looking for the default gateway.

When this failure occurs I can log into the AP where the client is associated and can see their machine listed in the "sh dot11 association" output.

The connection will come back up if the client resets the wireless card or disconnects/reconnects to the SSID.

This is happening with different hosts and device driver versions, so that doesn't seem to be the cause.  We are running mainly 1242AG's, but also have a 1220 and a 1231.  It doesn't seem to be a signal problem as it's happened to me multiple times and the AP is just about 15 feet away from my laptop.

Any ideas on what could be causing this?

[bauti1428]

A couple of reason why this might be happening.

1. Is it happening intermittently or specific times of the day? We had similar issue that happens during 11A to 1PM and we found out that the microwave oven is causing the interferance. Other causes of interferance will be from 2.4 wireless phones, Video camera, bluetooth, etc.

2. Make sure you have the latest version of your wireless card drivers.

3. Are you using any type of authentication espcially PEAP? If you do and running service pack 2 check the web site below

   http://support.microsoft.com/kb/885453

4. Is there a change on the layout of the room? Any change even small a drywall can change the way the signal travel especially glass doors, Mirrors, and metal beams.

[ben.bass0]

1.  I'm unable to get any type of consistency of when this happens.  I have seen it happen 5 times per day or it could go a month without ever happening..

2.  Updating drivers was the first thing that was done.

3.  Authentication is done with PEAP using two ACS servers which do Active Directory LDAP lookups.  The vast majority of our laptops are running Windows 7, but we have also seen it happen on a MacBook.

4.  No changes on the layout.