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.

[Saiprasad_Rao_R]

Any resolutions......

[James_A]

I'm running 9.21.10 and saw limited connectivity today on a rMBP connected to a 3825i. GTAC says it's hidden node, but the physical environment argues against that.

I also have an environment (of 3710i's) where clients are unable to connect despite a -55dBm signal, albeit through a brick wall. I'm going to do a lot of captures on this environment tomorrow.

FES: Interesting, I know on the Ubiquiti forums they say running different SSIDs on 2.4 and 5GHz helps.

[FES]

we have this option disabled, in apple devices dont change correctrly between 2,4 and 5 and the connection enter in stuk mode... we will test when we solve currentrly probelms.

[JP4]

We had the limited connectivity problem in 9.15.x also, especially with radio preference groups.

[FES]

the 9.21.8 fix the probe suppresion bug... you can see in release notes...you must trust hahaha.
maybe you can upgrade to 9.21.10... this version fix a pair of interesting bugs.