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.

[Sai_Prasad_Rao_]

Hi FES

I too feel timeout period has to be looked into

Is there any recommended time out value for pre and post in below cases:

1) Open WiFi Network
2) WiFi Network with pre shared key

[Sai_Prasad_Rao_]

Hi

I am also running on 9.21.8.x can I go ahead and implement above settings.......

[FES]

Sai,
Radar : Disabled
Probe Supression: Enabled
Force Dis association: Enabled -80db
Arp Proxy: Disabled on B@AP under wireless topology
Software Version Running: 9.21.8.13
Minimum Data Rate on 2.4Ghz & 5Ghz radio: 6Mbps
....
Dynamic Channel: Monitor
AutoTX Power: Disabled

We are testing with SESSION_TIMEOUT at radius server, because we have desconexions on macbook at the time in the field timeout (post) in Wlan service -> Avanced.
For all other devices all is ok.

At the end of the day i will give you more details.

[Sai_Prasad_Rao_]

FES, I did'nt get you . Can I have a detailed explanation of what exactly has been done @ your test environment. So that I can make the changes at my setup.

Radar : Enabled / Disabled
Probe Supression: Enabled / Disabled
Force Dis association: Enabled / Disabled
Arp Proxy: Enabled / Disabled on B@AP under wireless topology
Software Version Running: 9.21.x.x or 10.x.x.x
Minimum Data Rate on 2.4Ghz & 5Ghz radio

Thanks & Regards
SaiPrasad Rao Rapolu

[FES]

In our test enviroment the solution was ok last friday with no desconexions for the clients. We are going to apply to all infraestructure today, and become to do test for roaming.