Before association with an Access Point (AP), Stations (STAs) need to identify and select which AP to associate with. This process typically involves both passive and active scanning. In passive scanning, STAs listen for Beacon frames sent periodically by the AP to advertise its presence and SSID. In active scanning, STAs send out Probe Request frames to solicit responses from APs within range. The AP then replies with Probe Response frames, providing the SSID and other information. Thus, the packets involved in this process are Beacon, Probe Request, and Probe Response.