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Problems staying connected - Dell Latitude ST (1535C Half MiniCard Atheros based wifi)

chris.brunt
Level 1
Level 1

I have some Dell Latitude ST Windows 7 tablets and I am having major problems getting them to stay connected to wifi. They have the Dell wireless branded 1535C pci-e half minicard, which is atheros based and is running the only and latest driver I can find (3.1.2.41)

The devices connect to wifi but stop working after about 30-60 seconds and you sometimes have to completely reboot the tablet to get it to connect again. Basically you notice network activity stops and you get a limited conectivity exclaimation mark on the wireless icon in the systray.

Cleanair 3502i AP + some 1142N

3750G PoE Switches

WISM1 running 7.0.116.0

At the moment I have gone back to a simple WPA2 AES PSK wlan. It was the same with 802.1x authentication.

This device is connecting flawlessly on my Netgear router at home which is a WPA2 AES dual band 2.4 5ghz 802.11n.

Debugs Attached.

Any ideas would be good.

39 Replies 39

andersonch
Level 1
Level 1

I am having the same issue.  Dell is no help.  Any updates?

daviwatk
Level 3
Level 3

The debug indicates that your client entered the RUN state successfully at 16:58:17.451

*apfReceiveTask: Jan 30 16:58:17.451: e4:d5:3d:63:49:ab 192.168.254.158 DHCP_REQD (7) Change state to RUN (20) last state RUN (20)

Approximately 6 minutes later we de-authenticate the client with the reason...

*spamReceiveTask: Jan 30 17:04:48.540: e4:d5:3d:63:49:ab Received Idle-Timeout from AP 10:8c:cf:b0:43:10, slot 0 for STA e4:d5:3d:63:49:ab

*apfReceiveTask: Jan 30 17:04:49.455: e4:d5:3d:63:49:ab Sent Deauthenticate to mobile on BSSID 10:8c:cf:b0:43:10 slot 0(caller apf_ms.c:5094)

The client hit the WLC's default "user idle timeout" (Found in the WLC GUI at CONTROLLER > General > "User Idle Timeout (seconds)", which has a default of 300 seconds (5 minutes).  This is how long we will keep a client entry for a client we do not "hear" from (ie. a client that is not communicating at all; which ideally would be a client that has been turned off or left the service area)

This indicates that the client simply does not communicate to the AP for 300 seconds (or whatever your time is set to).

To "see" if this is really the case; does the tablet stay connected when you have initiated a continuous ping to, say, its gateway?  This sounds like it may be an issue "specifically" between the AP and client.

If the ping keeps the session active, I would highly suggest taking an over-the-air capture on the same channel as the AP to listen to the client/AP communication along with a simultaneous wireshark capture on a problem test client.  If the client is initating traffic (via wireshark); is it actually hitting the air(omnipeek)?  Is the traffic being ignored by the AP?  Over-the-air will be a tell all in this situation.

JroseTCMC
Level 1
Level 1

Our school also has 10 of these Tablets and we are experiencing the same issues you have described here. We ar running a Cisco 5508 Controller with 1142 AP's. I did have one ST stay connected for about 3-4 minutes at one point. But I cannot seem to keep them connected at this point. We did a trouble on the wireless card and found the drivers were stating they were not correctly installed. I have tried multiple fixes for this issue and have found nothing that will resolve it yet. Will be collaberating with our Network Admin tomorrow to do logging of this error. I would apperciate any help at this point. Thanks!

Make sure client load balancing is disabled under the WLAN SSID advanced tab.

Thanks,

Scott Fella

Sent from my iPhone

-Scott
*** Please rate helpful posts ***

JroseTCMC
Level 1
Level 1

Scott,

We have tried this today and that did not solve our issue with these tablets.

David,

We have tried pinging our gateway continously from the tablet and the connection still drops.

We are recieving the same timeout message as the orignal poster and have not come across a solution as of yet. Any more thoughts and ideas are welcome. The timeout period of 300 seconds is MUCH shorter than the actual time the tablet is "connected" to the AP. So we are at a loss on trying to figure out why this issue is happening.

-Joshua Rose

Systems Support Tech

The Commonwealth Medical College

Well just keep that disabled. Do you have both wpa/tkip and wpa2/aes enabled on the SSID?

Thanks,

Scott Fella

Sent from my iPhone

-Scott
*** Please rate helpful posts ***

JroseTCMC
Level 1
Level 1

Yes we are using WPA2 Enterprise and AES

Okay.... I don't know what you have done yet as far as troubleshooting, the only thing I would do to see if its an issue with the client side is create a test ssid and leave everything as default except for the status, interface and change the encryption to none, keeping everything else default, if your client still has issues, then it almost looks like Dell would have to be involved.  I'm also assuming every other device is working without any issues, just these Dell's.  The only other thing is maybe on the client device is to disable power save mode.

-Scott
*** Please rate helpful posts ***

We have tried tethering it to a mobile Verizon 3G WiFi and it stayed connected to that device for over and hour and half last night. We have tried connecting the device in multiple signal strength locations in our building with no luck. We Have been able to connect the device via a USB adapter to a wired connection to our network. We have also tried connecting them to our guest network which only allows outside access to the internet. The connection issue seems to be between the tablet and the AP. I am thinking at this point it has to be Dell issue related to drivers or something in the software package from the factory that is killing the connection. Not sure why this is such an issue, tried an update for drivers and bios on them and neither has seemed to clear the issue. All of our other devices on campus are working perfect.

Yeah... looks like its a Dell issue.... time to get on the Dell rep for some answers:)

-Scott
*** Please rate helpful posts ***

at home u only have 1 ap? when i had this problem the clients were roaming trying to find all the aps at my corp. i turned down the roaming aggressive setting on the nic and fixed it

Sent from Cisco Technical Support iPad App

andersonch
Level 1
Level 1

After spending multiple hours working on it I decided to give up and put it on Dell's lap.  I have an open ticket with them so hopefully they will be able to duplicate the issue.

I did find a workaround.  If you put the device on an SSID what has 802.11n turned off it works fine.  In my case I created a new SSID using WCS.  The QoS > WMM Policy is set to Disable.  Found those instructions here

https://supportforums.cisco.com/thread/2007749

This can also be done if an LWAPP controller is used.  I do not know if it can be done to an autonomous AP since I don't have one.

Hi everyone I have tried disabling 802.11n by disabling WMM made no difference. Also tried going to b/g only, again no difference. I also have MFP disabled at the moment as well due to an issue with some Intel cards.

I have a tread on the dell forums regarding this issue. Feel free to post on this thread to attract some attention from dell.

http://en.community.dell.com/support-forums/mobile-devices/f/3824/p/19436479/20052368.aspx#20052368

It could be faulty hardware Thomas Enchelmeier but I have four of these tablets and they are all doing the same thing.

I have exactly the same problem. The ST is online for 20-30 seconds after boot or after waking up from standby. Removing the driver or updating it causes the OS to hang, so I have to switch off hard. It's the original DELL W7 Pro Image.

I've just called the DELL Pro Support. They never heard about such a problem with the 1535C and they suppose defective hardware. Tomorrow a technician will come to change the card. I'll keep you informed.

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