topic Re: high channel utilitization in Wireless

high channel utilitization

wabbot22 — Fri, 13 May 2022 07:50:53 GMT

Hi all,

we´ve a Wireless Enviroment vWLC 8.5 + 1852/1600 AP´s. We use 5GHz only. The enviroment runs since several years.

Now we´ve got 2 1600 AP´s which show´s 100% Channel Utilitization ans also 100% Interference. Between both AP´s there is a big distance, so they can´t see each other. During this situation the clients are not able to connect to the two AP´s, and also debuggig on the AP´s doesn´t show any wireless traffic.

After a reload of both AP´s everything was ok.... I´ve also used a spectrum analyzer and can´t see any interference....

@one of the AP´s is 2,4GHz enabled but only for a test SSID, not for normal use, just for information....

Do anyone have an idea, what could be the reason ?

Thanks M

Re: high channel utilitization

Mark Elsen — Fri, 13 May 2022 08:22:25 GMT

- Review this thread for hints : https://community.cisco.com/t5/wireless/channel-utilization/td-p/2716667

Re: high channel utilitization

Flavio Miranda — Fri, 13 May 2022 10:08:56 GMT

Probably a software faulty. Radio in 5.0 Ghz to get legitimy 100% Ch. Util. needs to be in a very crowded environment (high density) with lots of AP around. It is very dificult to find AP with 5.0Ghz spectrum saturated, unless of corse, you are using channel greater then 40 Mhz.

The fact that the AP has 2.4ghz enable and even being used, does not interfere with 5.0ghz.

Another important information. External interference as you would get with Spectrum analyzer does not increase Ch. Util (CU).

CU gets high with clients using the channel not with interference. External interference can cause low SNR due the increase of noise floor. Low SNR can cause retransmition on wireless interface and this can cause high Ch. Util. but no the external interference directly.

Re: high channel utilitization

Leo Laohoo — Fri, 13 May 2022 11:12:36 GMT

@wabbot22 wrote:

Now we´ve got 2 1600 AP´s which show´s 100% Channel Utilitization ans also 100% Interference.

What radio and what channel?

Re: high channel utilitization

Rich R — Fri, 13 May 2022 13:08:28 GMT

If AP reload resolved it then almost certainly a software bug. What release of software are you running?

Re: high channel utilitization

wabbot22 — Sat, 14 May 2022 14:28:24 GMT

Yes after a reload everything was fine. 8.5.182.0.

It was on channel 40/44....

Re: high channel utilitization

Rich R — Mon, 16 May 2022 22:36:45 GMT

8.5.182.0 is the last and latest release to support 1600 and they're now end of support

https://www.cisco.com/c/en/us/products/collateral/wireless/aironet-1600-series/eos-eol-notice-c51-737506.html

so whatever the bug that caused that - it won't get fixed. You may find you just have to reload them occasionally until you can replace them with newer APs.