Router

A device that transfers data packets from one local area network (LAN) or wide area network (WAN) to another. Routers see the network as addresses and all the possible paths between them. They read the address in each transmitted frame and decide how to send it based on the most expedient route (traffic load, line costs, speed, bad lines, etc.). Because routers have to inspect the network address in the protocol, they do more processing and add more overhead than a bridge or switch. Routers work at the network layer (OSI layer 3), whereas bridges and switches work at the data link layer (OSI layer 2).

Routers are also used to segment LANs to balance traffic, filtering traffic for security purposes, and controlling broadcast storms. Routers often serve as an internet backbone, interconnecting all networks in the enterprise.