Active vs Passive scanning in Wireless Networks I read that there are two ways a wireless client can scan for a wireless network. 1. By sending probe requests and listening for a response by APs within range (Active Scanning) 2. By waiting and listening for beacon messages from the AP within range (Passive Scanning) Why are there 2 ways of scanning? What determines which scanning option will be used? Also, is there any major difference between active and passive scanning, except for what I have mentioned above? Does one option offer any advantages over the other one?

> What determines which scanning option will be used?

It is up to the client to chose. If, for example, the client has a preferred network (or several), it may actively probe for that network.

If the client doesn't have a preferred network, it may passively listen for the available networks so the user can chose.

The client can also do both -- probe for a known network and listen for other available networks. This is typically what a PC will do.