When you send an email to your Aunt Jessie on the other side of the country, it is routing technology that makes sure she and she alone gets the message, and not every computer connected up to the Internet. Routers direct the flow of traffic among, rather than within, networks. For example, let us consider how routers can be used within a LAN to continue information flowing.

Design-O-Rama, as shown in the picture is a computer graphics company. LAN of the company is divvied into two smaller local networks - one for the animators and one for administration and support staff. The two subdivisions connected with a router. Design-O-Rama employs eight people - four designers and four other developers. When one animator sends a file to another, the large file will use high capacity network. This leads to performance issue for other network.

To remain the designers continuous slowing down the network, the network was divided into two-one for designers and one for everyone else. The router connects two networks and connects both to the Internet. The router is the only device on the network sees every message sent from any computer or network. When one animator sends a file to a colleague, the router examines the address of the recipient and that keeps track of traffic that isolated LAN. On the other hand, if the designers want to explore the human relations division about vacation time, the router knows to leave that bit of traffic through the Human possessions.