NCTI Introduction to Networking – Wireless Practice Test

In WLAN discovery, there are two ways to find networks: passive and active scanning. Passive scanning simply listens on each channel for beacon frames that access points periodically broadcast to announce their presence and capabilities. You don’t transmit anything; you just wait and capture what’s already being advertised. Because you’re not sending extra frames, airtime usage is lower and the process can take longer if beacons aren’t heard promptly or if the APs are far away.

Active scanning, on the other hand, involves the client sending probe requests on each channel. Access points that receive those probes respond with probe responses (or beacons reappear after responds), providing the network information quickly. This tends to speed up discovery but uses more airtime due to the additional probe/response traffic and the channel activity it creates, and it can consume more power as well.

The statement that correctly contrasts the two methods captures this: passive scanning listens for beacons, while active scanning sends probe requests and collects responses, resulting in faster discovery but more airtime. The other options mix up which method sends probes or misstate the speed trade-off, so they don’t fit.