The primary function of an Access Point is to bridge the gap between wired and wireless networks by allowing wireless clients to connect to a wired network infrastructure. This is fundamental for creating a wireless network as it provides the necessary interface for wireless clients to communicate with wired network resources and the internet. A Router, although it can sometimes incorporate the functions of an access point, primarily directs traffic between different networks. A Switch mainly operates in wired networks to connect devices within the same network, and a Hub serves a similar purpose but does not manage traffic as efficiently as a switch.