ABSTRACT
The Internet comprises a mesh of routers interconnected by links, in which routers forward packets to their destinations, and physical links transport packets from one router to another. Routers knit together the constituent networks of the global Internet, creating the illusion of a unified whole. In the Internet, a router generally connects with a set of input links through which a packet can come in and a set of output links through which a packet can be sent out. Generally, routers consist of the following basic components: several network interfaces to the attached networks, processing module(s), buffering module(s) and an internal interconnection unit. Routing protocols are the means by which routers gain information about the network. Routing protocols map network topology and store their view of that topology in the routing table. Routers are the core equipment in the Internet, and are found at every level in the Internet.
