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.

[Andre_Brits_Kan]

https://gtacknowledge.extremenetworks.com/articles/Solution/Wireless-Clients-has-performance-and-con...

[James_A]

Hi Andre, in that location I fiddled with the power and was unable to reproduce it afterwards. I do have some cases open, one for clients getting 169.254 addresses after roam, one for performance problems, but both are intermittent so reproducing them is hard. School came back today and we haven't had any complaints so far which is good.

[Andre_Brits_Kan]

Hi JamesA Did you manage to get all your traces? Do you have any resolution? Have you opend a case for your problems?

[Sai_Prasad_Rao_]

disconnections are still there, I have not done the above mentioned settings.

Will do it as early as possible.

I am just concerned about the timeout period ( both pre and post )

What should the values be for:
1) Open WiFi network
2) WiFi with pre shared key

Kindly suggest , we are part of education institute. Where we have class rooms as well as hostels.

[FES]

I think this values are ok, because is for idle timeout. If the client is using the wifi network this value is omited.

Your desconexions are fixed??