The difference between active scanning and passive scanning
Knowledge of active and passive scanning
For a station, if you want to connect to the AP, you must first discover the AP. There are two ways to find out: passive scanning (passive scan) and active scanning (active scan). Remember two keywords: passive-listen! Hey, take the initiative-search!
Passive-listen to what? -beacon beacon
Take the initiative-what do you search with? -probe requests [this frame can carry SSID or use Null SSID]
Note: if the client discovers through active scanning that many AP have the same SSID, it will choose the best AP connection based on signal strength and signal quality, and usually the client will continue to send probe request on other channels to get a list of available AP for roaming.
