Wireless clients sporadically getting Limited Connectivity, APs dropping packets

[John_Rowler]

We have a pair of V2110 wireless controllers and around 400 3825i access points. Controller firmware is 09.21.06.0002. AP firmware is 9.21.27.1387X.

About 4 months ago we noticed a problem where the APs would just drop traffic. A packet capture will show a ping coming into the radio from the client, going out the Eth interface on the AP, the reply coming back into the Eth interface, and never going out of the radio.

A particularly strange detail is that this only happens with certain source/destination traffic. For instance a client cant ping the gateway of 10.1.20.1/24. but cannot pint the server at 10.1.20.2. Since we can see the ping making it to the server and the ping reply making it back to the AP, we know it's not a firewall/ACL/routing issue on any other part of the network. The traffic disappears at the AP. Clients cannot communicate with anything on the Internet or any of our servers (DNS, DHCP, etc.) during this time. They can ping gateways in any subnet but that's it; everything else is failed.

More details:

-We've gone through several firmware updates with GTAC. Nothing has helped.
-The issue can affect any client on any AP in any location at any time.
-The issue is intermittent; it may happen every few minutes or once per month to a particular client in a particular area. Once failed it may last for seconds or days.
-While it's affecting one client, other clients on the AP may be working fine or may also fail.
-It can happen on either 2.4 or 5.7GHz.
-It can affect any type of client (phone, laptop, tablet) and any OS.
-Restarting the client or AP will sometimes fix the issue, sometimes not.
-It happens with our without using NAC, or any other type of authentication. It happens on completely open networks as well.
-It happens on both bridged at AP and bridged at controller topologies.
-It's not limited to a particular subnet or VLAN.
-It happens with or without Flexible Client Access enabled.
-It happens on either controller.
-GTAC hasn't made much progress on the issue in 4 months.

[Ronald_Dvorak]

The function was introduced in V4 and allows a client to request certain information that are not included in the probe request.... i.e. DTIM information element (IE).

[JP4]

FES, what does having "Process client IE request " enabled do ?

[Sai_Prasad_Rao_]

Hi

We have same dis connectivity issue, We have C5210 controllers with 3805i Access Points , TAC said to Upgrade to version 9.21.10.5 will resolve the dis-connectivity issues

Along with upgrade. you will have to change Radio 2 settings from b/g/n to g/n , enable probe suppression with threshold -80 dbm, enable force dis association.

[FES]

Saiprasad, if you dont have the same version 9.21.08 this settings couldnt works.
We are testing on 802.1x network (most important in our institution).
With this enviroment... the most important that we have configured
*At wlan service -> Avanced button -> only process IE request enabled
* At wlan service -> Privacy tab -> oportunistic and preauth, rekey enabled 3600 sec, Management FT disabled, fast transition disabled,
* No ap groups configured like band select or load balancing.
* At Aps->
Auto tx disabled
3 channel plan
Monitor mode selected
Probe suppresion disabled
min rate 6mbps

of course this options works fine in my enviroment, it possible that desnt works fine at yours.
le me know if solve your desconexions.
Be careful with intel drivers, we are solved some problems in devices updating the intel driver... There are one bug fixed by Extreme in 10.x enviroment with intel drivers, but there are no info for 9.21.xxx .
Regards

[Saiprasad_Rao_R]

Can I have the settings with which things have worked out for you..........