ABSTRACT
Internet routers are devices that connect several packet switched networks to allow communication and resource sharing among a large group of users. A router implements the packet forwarding and routing functions of network layer which is the third layer of the seven-layer OSI model of computer networking. A router has several input and output ports through which it receives and sends packets. A packet arriving at an input port of a router is transferred to an appropriate output port and from here to its next hop on the path to its destination. A router maintains a list of rules in a forwarding table that is used to determine the next hops for packets during packet forwarding. A router updates its forwarding table continuously in response to changes in the Internet. All the routers in a network communicate with each other using routing protocols to remain updated of the changes and to select the best paths to reachable destination addresses.
