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.

[James_A]

Have you been able to capture any traces (RealCapture) or logs while it happens? Also, one way the problem I see can be fixed is to add another SSID to the radio, or change radio parameters (MBR, probe suppression, but not power), so try doing those to see if it's the same problem. There's log messages that signify the problem, but I'd say talk to GTAC to get them to tell you what to look for.

The good news is GTAC have finally been able to reproduce my problem, which is always the hardest part of getting any tech support case fixed. Meanwhile, rebooting the APs nightly will mask the problem, as it takes about a day to start occurring here.

[Scott_Van_Artsd]

Making plans to upgrade next week.

[Doug]

Any updates on how 9.21.07 is working out for everyone? So far the feedback has been positive.

We are still looking into some site specific problems that are not necessarily Extreme code related (settings, config issues, wifi client side issues).

[Evan_Kuckelheim]

I haven't heard anything since. We did have one area that the iOS devices only were getting a 169 address but after a ap reboot they have not persisted since. All other clients android/windows were not having problems in that area.

[FES]

thanks por the article Roland!!
Evan, do you know when the upgrade will be published?
thanks for the help