SWRU616B September 2023 – April 2024 CC3300 , CC3301 , CC3301MOD , CC3350 , CC3351
When the device is utilizing a passive scan, it spends a certain amount of time listening on each channel to receive beacons stating that an AP is available to connect to. After a period of time the device switches to the next channel and repeats the process. The beacon sent from APs to the station contains info elements (IE) such as the SSID, RSN, and country code that allow the device to know whether it is permitted to transmit on that channel.
A passive scan generally takes significantly longer to complete than active scan due to the device needing to spend much more time on each channel so that there is enough time for the APs to send a beacon. A similar process is followed on the active scan, where after waiting the necessary period of time, the device switches to a different channel to continue listening for beacon frames. Once the scan is completed, the available APs are stored in memory as possible connections.