Router

A router is a networking device that forwards data packets between computer networks.

The router is connected to at least two networks and decides which way to send each information packet based on its current understanding of the state of the networks it is connected to.

  

A router has two stages of operation called planes

Control plane: A router maintains a routing table that lists which route should be used to forward a data packet, and through which physical interface connection.

Forwarding plane: The router forwards data packets between incoming and outgoing interface connections. It routes them to the correct network type using information that the packet header contains. It uses data recorded in the routing table control plane.