What device is primarily responsible for connecting different networks?

The router is primarily responsible for connecting different networks. It functions at the network layer of the OSI model and is essential in facilitating communication between distinct IP networks. Routers use routing tables and protocols to determine the best path for forwarding packets. This capability allows routers to connect not only different local area networks (LANs) but also wide area networks (WANs), enabling data to travel from one network to another intelligently.

In contrast, switches primarily operate within a single network by connecting devices in a LAN and using MAC addresses to forward data frames. Hubs are simpler devices that also connect multiple devices within the same network but do not intelligently direct traffic, as they forward data to all connected devices without filtering. Bridges connect two or more network segments within the same network, helping to reduce collision domains but not interconnecting distinct networks. Thus, the router’s ability to facilitate communication between different IP networks is what makes it the correct answer in this context.