<P> In packet switching networks, routing is the higher - level decision making that directs network packets from their source toward their destination through intermediate network nodes by specific packet forwarding mechanisms . Packet forwarding is the transit of logically addressed network packets from one network interface to another . Intermediate nodes are typically network hardware devices such as routers, bridges, gateways, firewalls, or switches . General - purpose computers also forward packets and perform routing, although they have no specially optimized hardware for the task . The routing process usually directs forwarding on the basis of routing tables, which maintain a record of the routes to various network destinations . Thus, constructing routing tables, which are held in the router's memory, is very important for efficient routing . Most routing algorithms use only one network path at a time . Multipath routing techniques enable the use of multiple alternative paths . </P> <P> Routing, in a narrower sense of the term, is often contrasted with bridging in its assumption that network addresses are structured and that similar addresses imply proximity within the network . Structured addresses allow a single routing table entry to represent the route to a group of devices . In large networks, structured addressing (routing, in the narrow sense) outperforms unstructured addressing (bridging). Routing has become the dominant form of addressing on the Internet . Bridging is still widely used within localized environments . </P> <Table> <Tr> <Th> <P> Routing schemes </P> <P> </P> </Th> </Tr> <Tr> <Th> <P> unicast </P> <P> </P> </Th> </Tr> <Tr> <Th> <P> broadcast </P> <P> </P> </Th> </Tr> <Tr> <Th> <P> multicast </P> <P> </P> </Th> </Tr> <Tr> <Th> <P> anycast </P> <P> </P> </Th> </Tr> <Tr> <Th> <P> geocast </P> <P> </P> </Th> </Tr> <Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> </Table> <Tr> <Th> <P> Routing schemes </P> <P> </P> </Th> </Tr>

Difference between adaptive and non adaptive routing algorithms