03计算机网络习题.doc

Chapter 1 Computer Networks and the Internet 1．The ( ) is a worldwide computer network, that is, a network that interconnects millions of computing devices throughout the world. （）是一个全球性计算机网络，即一个网络设备互连世界各地数以百万计的电脑。公共内联网differ in that ( ). A datagram networks are circuit-switched networks, and virtual-circuit networks are packet-switched networks. B datagram networks are packet-switched networks, and virtual-circuit networks are circuit-switched networks. C datagram networks use destination addresses and virtual-circuit networks use VC. numbers to forward packets toward their destination. D datagram networks use VC. numbers and virtual-circuit networks use destination addresses to forward packets toward their destination. 9．In the following options, which one is not a guided media? ( ) A twisted-pair wire B fiber optics C coaxial cable D satellite 10．Processing delay does not include the time to ( ). A examine the packet’s header B wait to transmit the packet onto the link C determine where to direct the packet D check bit-error in the packet 11．In the following four descriptions, which one is correct? ( ) A The traffic intensity must be greater than 1. B The fraction of lost packets increases as the traffic intensity decreases. C If the traffic intensity is close to zero, the average queuing delay will be close to zero. D If the traffic intensity is close to one, the average queuing delay will be close to one. 12．The Internet’s network layer is responsible for moving network-layer packets known as ( ) from one host to another. A frame B datagram C segment D message 13．The protocols of various layers are called ( ). A the protocol stack B TCP/IP C ISP D network protocol 14．There are two classes of packet-switched networks: ( ) networks and virtual-circuit networks. A datagram B circuit-switched C television D telephone 15．Access networks can be loosely classified into three categ