In WLAN operations, two primary scanning methods are employed by client devices to discover available wireless networks:

Active Scanning:The client device actively sends out probe request frames on various channels. Access Points (APs) that receive these requests respond with probe response frames, providing information about the network. This method allows clients to discover networks even if they are not broadcasting their SSIDs.

Passive Scanning:The client device listens for beacon frames that are periodically transmitted by APs. These beacons contain information about the network, such as SSID, supported data rates, and security protocols. Passive scanning is less intrusive and does not generate additional traffic, but it may take longer to discover networks, especially if the beacon interval is lengthy.

Understanding these scanning methods is crucial for network design and troubleshooting, as they impact how quickly and efficiently clients can connect to available networks.