Hardware or software instruments which function is to redirect the flow of information, that is, indicate the destination of IP packages.
In IEEE 802 local area network (LAN) standards, routers are devices that connect autonomous networks of like architecture at the network layer (layer 3). Unlike a bridge which operates transparently to communicating end-terminals at the logical link layer (layer 2), a router reacts only to packets addressed to it by either a terminal or another router. Routers perform packet (as opposed to frame) routing and forwarding functions; they can select one of many potential paths based on transit delay, network congestion or other criteria. How routers perform their functions is largely determined by the protocols implemented in the networks they interconnect.
Routers are fundamental devices for operating the Internet and other computer-based communications networks. They send information by locating the number attached to a package of data, called the packet, and then searching for the most efficient transmission route. Such equipment originally was used only to connect computer networks, including local area networks (LANs). Cisco Systems Inc. of the U.S. is the world's leading router manufacturer. It became a bellwether U.S. high-tech company when popularization of the Internet spurred demand for routers. Japanese companies, which have been strong at producing telephone exchanges, have not performed well in the router market.