Hard to come back to DFS channel

[sergi_dupe]

I have an AP122 allowed to work on DFS channels.

Usually AP selects channel 136 because it is the only one transmitting on that channel (0 interferences from other APs nearby).

However, after detecting radar signals AP does not come back to that DFS channel after several days or even weeks. Logs keep saying this: “ah_dcd: wifi: [DFS-dcost] wifi1: Invalid channel 136” after radar signal disappears.

I thought that once radar signals are not detected anymore, AP would come back in a matter of minuter/hours.

Any hint?

Regards

[w1f1n00b · Accepted solution]

Coming back to this thread, I’ve since stopped using DFS channels, as I’ve been told by GTAC that APs do not perform background scans while on a DFS channel. This means no radio auto power adjustments, or rrm channel changes.

[gacpac]

I remember using DFS channels in a big area. tons of issues with IoT devices, a lot of manufactures don't support it. eg. roku and fire tv

[w1f1n00b]

I guess the question would be, is the channel the AP is changing to and staying on acceptable? It won’t specifically go back to the DFS channel it was on unless it was set manually and you check the box for “Enable manual channel selection return”. Otherwise my understanding is after the DFS event (and the 30 minute NOP) the AP will then resume normal ACSP (based on background scans).

[Paul_Wang]

@john_kern - 30 minutes is the NOP (Non occupancy period). If a radar signal is detected on a channel, that channel will not be used for at least 30 minutes.