topic Statically assigning DFS channels in Wireless

Statically assigning DFS channels

The_B — Mon, 05 Jul 2021 17:12:31 GMT

So if I statically assign DFS-required channels on my APs, what happens when radar is detected on that channel? Will the AP just stop transmitting? I haven’t been able to find any real information on this.

Thanks

Re: Statically assigning DFS channels

Flavio Miranda — Fri, 05 Apr 2019 14:31:51 GMT

Are we talking about autonomous AP ou Controller based AP? Either way the expected behavior should be:

"802.11 stations, before transmitting in a DFS channel, must validate (by first listening for 60 seconds) that there is no radar activity on it. And, if an 802.11 radio should detect radar while using the DFS channel, it must vacate that channel quickly. Thus, if a radio should detect radar in its serving channel, then switch to another DFS channel, this will impose (at least) a one-minute outage."

"When an access point (AP) uses a DFS channel and a radar signal is detected, the AP will behave as follow:

Stops transmission of data frames on that channel
Broadcasts an 802.11h channel-switch announcement.
Disassociates clients
Selects a different channel from the DCA (Dynamic Channel Assignment) list
- If the selected channel is not DFS then AP enables beacons and accepts client associations
- If the AP selects a DFS-required channel, it scans the new channel for radar signals for 60 seconds. If there are no radar signals on the new channel, the AP enables beacons and accepts client associations. If a radar signal is detected, the AP selects a different channel"

On the WLC is quite eady to setup it and let RRM to work for you.

-If I helped you somehow, please, rate it as useful.-

Re: Statically assigning DFS channels

The_B — Fri, 05 Apr 2019 14:37:27 GMT

Thank you for your reply!

So even if the channel is statically assigned, it will switch channels?

Thanks!

Re: Statically assigning DFS channels

gshipp001 — Mon, 24 Jun 2019 19:41:43 GMT

Also needing this information.

Thanks,

Re: Statically assigning DFS channels

timoffet — Thu, 10 Aug 2023 18:04:44 GMT

Thought I would complete this thread, answering the above question.

If radar is detected on a manually configured DFS channel, the channel will be changed automatically to a DCA channel and will not return to the manually configured channel. The rest of the manually defined channel plan will remain intact.

If you have is a mission critical wireless environment, and are considering the use of the DFS channel space, a DFS survey should be completed to gain an understanding of risk/feasibility.

***EDIT: This assumes that RRM is enabled. Without RRM, I believe the AP will shut down for 30 minutes per 802.11 standard. I am told that this is not a recommended or validated configuration (without RRM).

Hope this helps others!

Tim