计算机网络英文题库附答案chapter.docx

1、计算机网络英文题库附答案chapterChapter 1 Computer Networks and the Internet1The ( ) is a worldwide computer network, that is, a network that interconnects millions of computing devices throughout the world. ppt3A public Internet B IntranetC switch net D television net2Which kind of media is not a guided media?

2、( )A twisted-pair copper wire B a coaxial cableC fiber optics D digital satellite channel3Which kind of media is a guided media? ( )A geostationary satellite B low-altitude satelliteC fiber optics D wireless LAN4The units of data exchanged by a link-layer protocol are called ( ).A Frames B SegmentsC

3、 Datagrams D bit streams5Which of the following option belongs to the circuit-switched networks? ( )A FDM B TDMC VC networks D both A and B6( )makes sure that neither side of a connection overwhelms the other side by sending too many packets too fast.A Reliable data transfer B Flow controlC Congesti

4、on control D Handshaking procedure7( ) means that the switch must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link.A Store-and-forward transmission B FDMC End-to-end connection D TDM8Datagram networks and virtual-circuit networks differ in

5、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 network

6、s 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.9In the following options, which one is not a guided media? ( )A twisted-pair wire B fiber opticsC coax

7、ial cable D satellite10Processing delay does not include the time to ( ).A examine the packets headerB wait to transmit the packet onto the linkC determine where to direct the packetD check bit-error in the packet11In the following four descriptions, which one is correct? ( )A The traffic intensity

8、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.12The Internets n

9、etwork layer is responsible for moving network-layer packets known as ( ) from one host to another.A frame B datagramC segment D message13The protocols of various layers are called ( ).A the protocol stack B TCP/IPC ISP D network protocol14There are two classes of packet-switched networks: ( ) netwo

10、rks and virtual-circuit networks.A datagram B circuit-switchedC television D telephone15Access networks can be loosely classified into three categories: residential access, company access and ( ) access.A cabled B wirelessC campus D city areaQuestion 1617Suppose, a is the average rate at which packe

11、ts arrive at the queue, R is the transmission rate, and all packets consist of L bits, then the traffic intensity is ( 16 ), and it should no greater than ( 17 ).16 A LRa B LaRC RaL D LRa17A 2 B 1C 0 D -118In the Internet, the equivalent concept to end systems is ( ).A hosts B serversC clients D rou

12、ters19In the Internet, end systems are connected together by ( ).A copper wire B coaxial cableC communication links D fiber optics20End systems access to the Internet through its ( ).A modems B protocolsC ISP D sockets21End systems, packet switches, and other pieces of the Internet, run ( ) that con

13、trol the sending and receiving of information within the Internet.A programs B processesC applications D protocols22There are many private networks, such as many corporate and government networks, whose hosts cannot exchange messages with hosts outside of the private network. These private networks

14、are often referred to as ( ).A internets B LANC intranets D WAN23The internet allows ( ) running on its end systems to exchange data with each other.A clients applications B server applicationsC P2P applications D distributed applications24The Internet provides two services to its distributed applic

15、ations: a connectionless unreliable service and () service.A flow control B connection-oriented reliableC congestion control D TCP25It defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of

16、 a message or other event. The sentence describes ( ).A Internet B protocolC intranet D network26In the following options, which does not define in protocol? ( )A the format of messages exchanged between two or more communicating entitiesB the order of messages exchanged between two or more communic

17、ating entitiesC the actions taken on the transmission of a message or other eventD the transmission signals are digital signals or analog signals27In the following options, which is defined in protocol? ( ) A the actions taken on the transmission and/or receipt of a message or other event B the obje

18、cts exchanged between communicating entities C the content in the exchanged messages D the location of the hosts28In the following options, which does not belong to the network edge? ( )A end systems B routersC clients D servers29In the following options, which belongs to the network core? ( )A end

19、systems B routersC clients D servers30In the following options, which is not the bundled with the Internets connection-oriented service? ( )A reliable data transfer B guarantee of the transmission timeC flow control D congestion-control31An application can rely on the connection to deliver all of it

20、s data without error and in the proper order. The sentence describes ( ).A flow control B congestion-controlC reliable data transfer D connection-oriented service32It makes sure that neither side of a connection overwhelms the other side by sending too many packets too fast. The sentence describes (

21、 ).A flow control B congestion-controlC connection-oriented service D reliable data transfer33It helps prevent the Internet from entering a state of gridlock. When a packet switch becomes congested, its buffers can overflow and packet loss can occur. The sentence describes ( ).A flow control B conge

22、stion-controlC connection-oriented service D reliable data transfer34The Internets connection-oriented service has a name, it is ( ).A TCP B UDPC TCP/IP D IP35In the following options, which service does not be provided to an application by TCP?( )A reliable transport B flow controlC video conferenc

23、ing D congestion control36The Internets connectionless service is called ( ).A TCP B UDPC TCP/IP D IP37In the following options, which does not use TCP?( )A SMTP B internet telephoneC FTP D HTTP38In the following options, which does not use UDP?( )A Internet phone B video conferencingC streaming mul

24、timedia D telnet39There are two fundamental approaches to building a network core, ( ) and packet switching.A electrical current switching B circuit switchingC data switching D message switching40In ( ) networks, the resources needed along a path to provide for communication between the end system a

25、re reserved for the duration of the communication session.A packet-switched B data-switchedC circuit-switched D message-switched41In ( ) networks, the resources are not reserved; a sessions messages use the resources on demand, and as a consequence, may have to wait for access to communication link.

26、A packet-switched B data-switchedC circuit-switched D message-switched42In a circuit-switched network, if each link has n circuits, for each link used by the end-to-end connection, the connection gets ( ) of the links bandwidth for the duration of the connection.A a fraction 1/n B allC 1/2 D n times

27、43For ( ), the transmission rate of a circuit is equal to the frame rate multiplied by the number of bits in a slot.A CDMA B packet-switched networkC TDM D FDM44( ) means that the switch must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link

28、.A Queuing delay B Store-and-forward transmissionC Packet loss D Propagation45The network that forwards packets according to host destination addresses is called ( ) network.A circuit-switched B packet-switchedC virtual-circuit D datagram46The network that forwards packets according to virtual-circu

29、it numbers is called ( ) network.A circuit-switched B packet-switchedC virtual-circuit D datagram47In the following entries, which is not a kind of access network?( )A residential access B company accessC wireless access D local access48Suppose there is exactly one packet switch between a sending ho

30、st and a receiving host. The transmission rates between the sending host and the switch and between the switch and the receiving host are R1 and R2, respectively. Assuming that the switch uses store-and-forward packet switching, what is the total end-to-end delay to send a packet of length L? (Ignor

31、e queuing delay, propagation delay, and processing delay.) ( )A L/R1L/R2 B L/R1C L/R2 D none of the above49The time required to examine the packets header and determine where to direct the packet is part of the ( ).A queuing delay B processing delayC propagation delay D transmission delay50The time required to propagate from the beginning of the link to the n