Network routing is the process of selecting a path – or route – through one or more networks.
Because the Internet is a packet-switched network, routing selects the paths that Internet Protocol (IP) packets must take to get from their origin to their destination. These Internet routing decisions are made by specialized network devices called network routers¹.
If we use the image below as an example, for a data packet to go from computer A to computer B, there are two possibilities, or two routes. It can go through networks 1, 3 and 5 or through networks 2 and 4. Physically speaking, the packet will take a shorter route through networks 2 and 4. However, networks 1, 3, and 5 might be even faster at routing them. The network routers will choose the appropriate routes.
¹ Ordinary routers are used for home and office use to establish local network connections. Network routers are more powerful, as they work throughout the Internet helping data packets reach their destination.