单选题 An internet is a combination of networks connected by ______. When a datagram goes from a source to a ______, it will probably pass many ______ until it reaches the routerattached to the destination network. A router receives a ______ from a network and passes it toanother network. A router is usually attached to several networks. When it receives a packet, towhich network should it pass the packet? The decision is based on optimization: Which of theavailable ______ is the optimum pathway?

单选题 A. modems B. routers C. switcher D. computers

单选题 A. user B. host C. city D. destination

单选题 A. destinations B. routers C. packets D. computers

单选题 A. destination B. resource C. packet D. source

单选题 A. pathways B. routers C. diagrams D. calls