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.

[Chat]

Now have just released new firmware 09.21.09.0004. but we don't see this issue fixed in release notes.
We found on gtac "wns0014009" where say that this problem is fixed in firmware 09.21.08 or higher, but this is not true.

https://gtacknowledge.extremenetworks.com/articles/Solution/Users-randomly-lose-network-and-internet...

Has anyone tried the new firmware 09.21.09 ?

[FES]

Hi, we are testing configuren high values at sesion time fields and this mornig we have had no desconexions. I dont know why, maybe because is friday, or maybe because the infraestructure is afraid .
We are configure radius parameter Session-Timeout to 86400 seconds, and the fields in WlanService-> Advanced to 1440 min (the three fields that reffers to session values)
Other parameters in privacy tab:
WPAv1 disabled
WPAv2 enabled AES only
KeyManagementOptios Oportunistic and Preauth
Broadcast re-key 86400sec
MFP Disabled
FastTransition enabled

We are testing this configuration in our test enviroment.
We hope be helpful.

[Emre_Kurtman]

Hi FES, you have any case numbers that you can share for this issue?

[FES]

Hi JP,
we are in 9.21.08 We have minimiced the problem, but once a day we have de limited connection on iphone5s and macbook air devices...
The GTAC says that are working on it and we hope that it will be fixed in the next firwmare... about 18-20 of May.

[James_A]

That's interesting, one of the workarounds for the problem we had in 9.21.07 was to set the broadcast re-key to 86400s, which helped because it only occurred during re-key.

The other workaround was to reboot every night, which perhaps masked this problem too, so I'm going to enable the nightly maintenance schedule again.