Why router is important?

A router is a networking device that helps relay traffic from one network to another, and vice versa.

For example, a typical broadband internet connection router relays traffic from the private network within the home to the public (Internet) network outside. Rules dictate which portion of the traffic on either side passes through the router. For example, networking messages exchanged between a PC and a networked printer within the home will not pass the router and will thus not be "seen" on the public network, but a query to a public website, and its response, will.

Other commonly used routers include the WiFi routers, which relay traffic between a wired network and a wireless network.

Less common routers also handle different media, similar to a WiFi router. Examples include routers that relay traffic from a network using dedicated network cables to one that uses the power grid, and many others.