Did you ever think how your mail was sent to you from the source until it reached your mailbox in front of your house? It was distributed by means of the address which was included intoyour email.
That’s how a router works. That’s how a router do it. The router use the address to locate where it should be forwarded same as for your mail which was being dropped into your mailbox.
The router uses kind of address which is based on TCP/IP (Transmission Control Protocol over Internet Protocol) called IP (Internet Protocol) to route its data. The data that is being routed by the route is called packet. The packet contain PDU, Source Address, and Destination IP Address. The router finds the best route from its neighbor router, and this is called routing.
Router looks like down below:
Cisco 1721 Router Courtesy: http://www.esellerpro.com