What a Router Actually Does

Switches connect devices within one network, but to reach a different network — like a website on the internet — you need a router. A router's job is to move traffic between separate networks, choosing the best path toward each destination. Routers are what stitch the world's networks into the internet. This lesson explains what a router really does and how it differs from a switch.

A router works at the network layer (Layer 3 of the OSI model), where data is addressed with IP addresses (Internet Protocol addresses). While a switch uses MAC addresses to move frames inside a LAN, a router uses IP addresses to forward packets between networks. This is why a router is a Layer 3 device and a switch is a Layer 2 device.