Deselecting DFS channels

[nipun_m]

Hi All,

I have implemented Meraki MR76 APs in a factory environment with external directional antennas. Eventually some APs are alerting DFS and radar events. As my understanding, in a radar event detection within a DFS channel, existing clients are disassociating. I need to how this will impact to client connectivity and by deselecting DFS channel in 5GHz how that will impact to the client connectivity ?

[Brash]

That's correct, during a DFS event, the AP will disconnect all clients from its 5Ghz radio and change channel before allowing them to reconnect. If this is a rare event, depending on the client device the end user may not even notice. If it's occurring frequently, it will begin to have a noticeable effect.

You can exclude DFS channels from the AutoRF channel assignment using Radio Settings.

If it's only specific AP's, you can even isolate the profile to only the AP's seeing the events.That will simply limit the number of channels available for your deployment. Unless you're in a very high-density deployment scenario, you likely won't see any negative impact.

See the below doc for more detail.

Dynamic Frequency Selection (DFS) - Cisco Meraki Documentation

[KarstenI]

This is a perfect use case for the new Auto RF functionality with AI. At least when you have repeated events on multiple APs. It will take care of the channels and ensure that only the relevant APs are excluded from those impacted.

For the client impact at a DFS event, the AP will send a Channel Switch Announcement before moving to the new channel, giving the client an experience comparable to a roam. But as usual, it doesn't always work that smoothly with all clients.

[nipun_m]

@Brash @kari , I deselected DFS channels in all APs. Now there are DFS events are alerting on multiple APs in non DFS channels ( 149,153). What will be the reason for this ?

[KarstenI]

I would open a support case for that as there should not be DFS events. Of course, there could happen events based on other interferences.

[cmr]

Are you using WiFi 6 models and if so do you have 30.6?  Prior versions have a channel change problem that makes a right mess of this!