off-channel scanning 简单笔记

参考
【 https://www.wi-fi.org/knowledge-center/faq/what-is-off-channel-scanning-for-wi-fi-access-points-aps 】
【 https://www.wi-fi.org/knowledge-center/faq/what-is-off-channel-scanning-for-wi-fi-client-devices 】

What is off-channel scanning for Wi-Fi client devices?
Off-channel scanning is when a Wi-Fi client device tunes its radio to another channel to look for available APs or scans for APs on a channel to which it is not connected (hence “off-channel”). The client scans the off-channel APs looking for a suitable AP to connect to in case it needs to roam from its current ‘on-channel’ AP.

What is off-channel scanning for Wi-Fi access points (APs)?
An access point (AP) can also perform off-channel scanning. This process is the same as off-channel scanning for Wi-Fi client devices and essentially allows the AP to tune its radio to a different channel for a finite amount of time. Off-channel scanning is typically used as a method to detect sources of interference, rogue or unauthorized ad-hoc Wi-Fi networks. The operation of performing off-channel scanning is highly dependent in terms of manufacturer implementation and configuration of the WLAN.