topic Re: Clients are dropping when usage is high in Wireless

Clients are dropping when usage is high

timgrantham — Wed, 02 Feb 2022 20:01:57 GMT

Hi,

I've tried everything that I can think of, and this is a strange one to me.

I have a 9130AXI single AP, with EWC 17.7.1, whenever a client is transferring at high speed on the 5GHz radio, all clients drop off, including the one transferring data, move off to the 2.4GHz for a few seconds, and then back to the 5GHz radio for a while, and then after 30 seconds it will go back to 2.4 and so it continues.

It's almost as though if it hits 80% on the radio usage, then it will do something that will say I've had enough go somewhere else.

But if this is the case, I can't find anything that is set that would cause this.

Any help would be really appreciated!

-Tim

Re: Clients are dropping when usage is high

Haydn Andrews — Wed, 02 Feb 2022 21:15:44 GMT

Couple of things:

First 17.7.1 isn't Cisco's current recommended version it is 17.6.2: https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/214749-tac-recommended-ios-xe-builds-for-wirele.html

You mention 80% can you confirm that load balancing is not enabled for the SSID?

What happens if you make the SSID 5 GHz only?

Also what channel is the 5GHz operating on, and how wide?

Can you provide the config of the WLC

Suggest conducting a radio trace on a couple of the clients and running the output through the debug analyser for an easier to read version: https://cway.cisco.com/wireless-debug-analyzer/

Re: Clients are dropping when usage is high

jagan.chowdam — Wed, 02 Feb 2022 21:43:35 GMT

Also, what's the AP Channel utilization (on AP 360 page) when client transmitting?

Re: Clients are dropping when usage is high

timgrantham — Thu, 03 Feb 2022 08:45:48 GMT

Hi Haydn,

Thanks for the reply.

If I make the channel 5GHz only then clients will drop, and rejoin that channel a short while after.

Point taken in relation to 17.7.1, and I will downgrade the access point to see if this makes any difference, there are no features that I need in 17.7.1 that isn't there in 17.6.2.

That's a good idea about the radio trace, I had forgotten all about that and will try it now!!

As for the utilisation, there does seem to be this 80% cut off as if I keep it below 79% by throttling what the NAS can send, then it's fine.

It's operating on channels 100 at 80Mhz wide.

Thanks for your help!!

Regards

-Tim

Re: Clients are dropping when usage is high

timgrantham — Thu, 03 Feb 2022 21:56:07 GMT

I tried 17.6.2 and re-did the configuration from scratch (it's only me using it here at home), and it still did it - so went back to 7.17.1 and this evening I have played with every setting I could find.

And boy are there a lot!

But it hasn't done it for the past hour since I disabled "Fastlane + ASR" in the WLAN profile.

Re: Clients are dropping when usage is high

Rich R — Fri, 04 Feb 2022 10:13:13 GMT

Interesting - sounds like a bug ...

Re: Clients are dropping when usage is high

Scott Fella — Fri, 04 Feb 2022 15:07:19 GMT

I always tell folks to keep the WLAN as simple as possible. Disable all the features and see how well it works. The issue with features, is that devices have issues connecting because either the device doesn't understand or support that setting or the ap implements the standard a different way that causes issues to the clients. When having issues, start with an open SSID and work your way up by adding features. Then test with PSK and 802.1x with adding one feature at a time.