An internet is a combination of networks connected by (71) . When a datagram goes from a source to a (72) . it will probably pass many (73) until it reaches the router attached to the destination network. A router receives a (74) from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available (75) is the optimum pathway?
