[justshowpost]

Scanning for least congested freq is very common, but it only performed right before upping of AP iface and no else. So sweeping the band with AP is very impractical.

[blobbers]

some of the higher end routers have an extra radio specifically for scanning. Ie: see Cisco

https://meraki.cisco.com/product/wi-fi/indoor-access-points/...

This thing will scan channels, as well as perform security operations.