Routing

Routing is a process of selecting best paths in a network. Also in the past the term rousing had a meaning of forwarding network traffic among networks. Routing is used for many kinds of network, such as telephone networks, electronic data networks, and transportation networks. Router is network device that forwards data packets between computer networks. This creates an overlay internetwork, as a router is connected to more then two data lines from different networks. The very first device which had approximately the same functionality as a router does today, was the Interface Message Processor (MIP).

Security

External networks must be carefully considered as a part of the overall security strategy. A router can include a firewall, VPN handling and other security functions. Many companies produce security-oriented routers which includes Cisco Systems’ PIX and ASA5500 series, Watch-guard’s Firebox and many others.

Routing algorithm

Routing algorithm determines the path selected by a packet to reach its destination. It must be selected within each intermediate router which output channels are to be selected for incoming packets.

Path selection

Routing metric to multiple routes was involved in path selection in order to select the best route. In computer network, the metric is computed by a routing algorithm. The routing table stores only the best possible route, where topological databases may store all other information.