topic Re: Force channel assignment - Radar problems in Wireless

Force channel assignment - Radar problems

Alfonsoj — Mon, 05 Jul 2021 16:42:04 GMT

First of all thanks for your help.I have a simple scenario with two RAPS and one MAP but I am suffering random disassociations from the MAP Access Point and the clients connected to this AP accordingly.

Checking at logs I notice that there is plenty of radar interruptions so I decided to disable DFS in order to avoid that interriptions using "config mesh full-sector-dfs disable" command.

Unfortunately the problem persist and I decided to force channels with the objective to avoid problematic channels selecting only channels 36 to 48 in DCA section, but I still can see AP connected to forbidden channels (136 and 100).

Configuring manually the AP channels only channels from 100 to 140 are available:

I am sure im missing something and i will really appreciate if can someone kindly put some light.

Many thanks in advance

Re: Force channel assignment - Radar problems

superego — Wed, 16 Jan 2019 19:46:30 GMT

Hi,

What code are you using?

Provide output using CLI:

show sysinfo

show mesh config

show advanced 802.11a channel

You can omit confidential stuff from the output.

Re: Force channel assignment - Radar problems

superego — Wed, 16 Jan 2019 20:05:01 GMT

I see the issue you have is that on Wireless>802.11a>RRM>DCA

The only thing you have is 36,44,48,52.

Since you only have these that's why you see DFS channel still as there are no other options and backhaul use channels 100> and up.

Add more channels by selecting checkbox thru GUI.

Or CLI,

config advanced 802.11a channel add 52

config advanced 802.11a channel add 56

config advanced 802.11a channel add 60

config advanced 802.11a channel add 64

config advanced 802.11a channel add 149

config advanced 802.11a channel add 153

config advanced 802.11a channel add 157

config advanced 802.11a channel add 161

HTH, please rate helpful posts.

Re: Force channel assignment - Radar problems

ajc — Wed, 16 Jan 2019 22:25:48 GMT

I know there is an identified bug on radar detection and we worked with TAC. But we did not want to disable the >100 channel where the DFS applies. In your case, I am not sure if the configuration you made is actually removing those >100 channels. Please check:

ap1520-rap # show mesh channels

Run a debug as indicated in the following link and provide output

https://www.cisco.com/c/en/us/td/docs/wireless/technology/mesh/8-1/design/guide/b_mesh_81/Troubleshooting.html#ID9488

Re: Force channel assignment - Radar problems

Alfonsoj — Thu, 17 Jan 2019 11:36:55 GMT

Hello Sir, thanks for your answer.

The product version is 8.5.135.0

attached the output you requested.

Thanks!

Re: Force channel assignment - Radar problems

Alfonsoj — Thu, 17 Jan 2019 14:30:52 GMT

Thanks so much for your reply!

thanks for your point of view but even activating the rest of ports:

I have the same limitation with custom channels:

Hope I understood your point.

Re: Force channel assignment - Radar problems

superego — Thu, 17 Jan 2019 14:44:35 GMT

Thanks for providing the output.

I see that you're using:

Configured Country............................... ES  - Spain

which falls under the ETSI regulatory domain and explains why you're unable to see the other channels as in North America does.

Re: Force channel assignment - Radar problems

Alfonsoj — Thu, 17 Jan 2019 15:02:46 GMT

Many thanks for your quick answer 🙂

Well, what you are telling make sense but there should be a way to once DFS is disabled use lower channels to avoid the radar interference. This is disconnecting the clients and it is a real nightmare.

thanks in advance

Re: Force channel assignment - Radar problems

Alfonsoj — Thu, 17 Jan 2019 16:30:31 GMT

Hi Mister:

Can you kindly be a little more specific? I am sending the commands with no feedback so I assume (of course) that i am doing something wrong

thanks in advance Sir

Re: Force channel assignment - Radar problems

superego — Fri, 18 Jan 2019 12:58:04 GMT

Only U-NII-2C band can be used for backhaul channels that's why you'll only see channels 100-140.

Europe

U-NII-1

23 dBm Maximum - Not permitted for outdoor usage

U-NII-2A

23 dBm Maximum - Not permitted for outdoor usage

Reference:

https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/Enterprise-Mobility-8-5-Design-Guide/Enterprise_Mobility_8-5_Deployment_Guide/Chapter-8.html

Re: Force channel assignment - Radar problems

superego — Fri, 18 Jan 2019 13:12:25 GMT

Since you have limited channels which are also DFS channels.

Solution i can think of is that you set Backhaul Channel width to 40/80 MHz.

In this way, you'll still have redundancy like if you use 80 MHz, 4 channels will be used so if a radar swept on one channel, you still have another channel that works.

***Please mark post that is helpful / mark as a solution

Re: Force channel assignment - Radar problems

Alfonsoj — Mon, 21 Jan 2019 09:28:12 GMT

Sirs, thanks so much for your ideas and support. I am waiting remote access to test latests solutions. In the meantime I was thinking that adding 2 more antennas for each AP (4 in total per each AP) can help to avoid the AP disassociation?

Make it sense for you?

Thanks in advance

Re: Force channel assignment - Radar problems

superego — Mon, 21 Jan 2019 15:49:54 GMT

All the backhaul channels in your 5GHz domain are on DFS. Try setting the backhaul Channel Width to 80 MHz.

Adding more antenna will still have same effect just give more bandwidth.

Re: Force channel assignment - Radar problems

patoberli — Tue, 22 Jan 2019 14:32:08 GMT

If you have only attached 2 of the 4 antennas, have you disabled the antenna-ports correctly in the configuration? Otherwise you will also have other issues, like no or extremely bad performance.