Which device is primarily used to connect different networks for internet access?

The device that is primarily used to connect different networks for internet access is the router. A router functions as a gateway between multiple networks, directing data traffic between them and ensuring that it reaches its intended destination efficiently. It manages the communication between your local network and the internet, making decisions about the best paths for data to travel across various interconnected networks.

By assigning IP addresses to devices on a local network and providing network address translation (NAT), the router allows these devices to share a single external IP address for internet connectivity. This capability makes routers essential in both home networks and larger enterprise environments, where numerous devices require access to the internet.

Other devices mentioned, like switches and access points, serve different functions. Switches primarily operate within a single local area network (LAN), connecting devices together but not facilitating external internet access. Access points extend wireless connectivity within a network but also do not manage the data flow between different networks. An extranet, on the other hand, is not a device but a secure extension of an organization's intranet to allow controlled access to partners or customers.