Router

Router
A network device that forwards data packets from one network to another. Based on the address of the destination network in the incoming packet and an internal routing table, the router determines which port (line) to send out the packet (ports typically connect to Ethernet cables). Routers require packets formatted in a routable protocol, the global standard being TCP/IP, or simply "IP."

Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts

-Jason Munro EC1417115