10-11D1XQR《计算机网络》复习题及答案

1、精选优质文档-倾情为你奉上Chapter 1 Computer Networks and the Internet1.The (A) is a worldwide computer network, that is, a network that interconnects millions of computing devices throughout the world.A.public Internet B.IntranetC.switch net D.television net2.Which kind of media is not a guided media? (D)A.twis

2、ted-pair copper wire B.a coaxial cableC.fiber optics D.digital satellite channel3.Which kind of media is a guided media? (C)A.geostationary satellite B.low-altitude satelliteC.fiber optics D.wireless LAN4.The units of data exchanged by a link-layer protocol are called (A).A.Frames B.SegmentsC.Datagr

3、ams D.bit streams5.Which of the following option belongs to the circuit-switched networks? (D)A.FDM B.TDMC.VC networks D.both A and B6.(B)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.Congestion co

4、ntrol D.Handshaking procedure7.(A) 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.TDM8.Datagram networks and virtual-circuit networks differ in tha

5、t (C).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 u

6、se 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? (D)A.twisted-pair wire B.fiber opticsC.coaxia

7、l cable D.satellite10.Processing delay does not include the time to (B).A.examine the packets headerB.wait to transmit the packet onto the linkC.determine where to direct the packetD.check bit-error in the packet11.In the following four descriptions, which one is correct? (C)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.12.The Internets

9、network layer is responsible for moving network-layer packets known as (B) from one host to another.A.frame B.datagramC.segment D.message13.The protocols of various layers are called (A).A.the protocol stack B.TCP/IPC.ISP D.network protocol14.There are two classes of packet-switched networks: (A) ne

10、tworks and virtual-circuit networks.A.datagram B.circuit-switchedC.television D.telephone15.Access networks can be loosely classified into three categories: residential access, company access and (B) access.A.cabled B.wirelessC.campus D.city areaQuestion 1617Suppose, a is the average rate at which p

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

12、lients D.routers19.In the Internet, end systems are connected together by (C).A.copper wire B.coaxial cableC.communication links D.fiber optics20.End systems access to the Internet through its (C).A.modems B.protocolsC.ISP D.sockets21.End systems, packet switches, and other pieces of the Internet, r

13、un (D) that control the sending and receiving of information within the Internet.A.programs B.processesC.applications D.protocols22.There are many private networks, such as many corporate and government networks, whose hosts cannot exchange messages with hosts outside of the private network. These p

14、rivate networks are often referred to as (C).A.internets B.LANC.intranets D.WAN23.The internet allows (D) running on its end systems to exchange data with each other.A.clients applications B.server applicationsC.P2P applications D.distributed applications24.The Internet provides two services to its

15、distributed applications: a connectionless unreliable service and (B) service.A.flow control B.connection-oriented reliableC.congestion control D.TCP25.It defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmissi

16、on and/or receipt of a message or other event. The sentence describes (B).A.Internet B.protocolC.intranet D.network26.In the following options, which does not define in protocol? (D)A.the format of messages exchanged between two or more communicating entitiesB.the order of messages exchanged between

17、 two or more communicating entitiesC.the actions taken on the transmission of a message or other eventD.the transmission signals are digital signals or analog signals27.In the following options, which is defined in protocol? (A) A.the actions taken on the transmission and/or receipt of a message or

18、other event B.the objects exchanged between communicating entities C.the content in the exchanged messages D.the location of the hosts28.In the following options, which does not belong to the network edge? (B)A.end systems B.routersC.clients D.servers29.In the following options, which belongs to the

19、 network core? (B)A.end systems B.routersC.clients D.servers30.In the following options, which is not the bundled with the Internets connection-oriented service? (B)A.reliable data transfer B.guarantee of the transmission timeC.flow control D.congestion-control31.An application can rely on the conne

20、ction to deliver all of its data without error and in the proper order. The sentence describes (C).A.flow control B.congestion-controlC.reliable data transfer D.connection-oriented service32.It makes sure that neither side of a connection overwhelms the other side by sending toomany packets too fast

21、. The sentence describes (A).A.flow control B.congestion-controlC.connection-oriented service D.reliable data transfer33.It 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

22、 (B).A.flow control B.congestion-controlC.connection-oriented service D.reliable data transfer34.The Internets connection-oriented service has a name, it is (A).A.TCP B.UDPC.TCP/IP D.IP35.In the following options, which service does not be provided to an application by TCP? (C)A.reliable transport B

23、.flow controlC.video conferencing D.congestion control36.The Internets connectionless service is called (B).A.TCP B.UDPC.TCP/IP D.IP37.In the following options, which does not use TCP? (B)A.SMTP B.internet telephoneC.FTP D.HTTP38.In the following options, which does not use UDP? (D)A.Internet phone

24、B.video conferencingC.streaming multimedia D.telnet39.There are two fundamental approaches to building a network core, (B) and packet switching.A.electrical current switching B.circuit switchingC.data switching D.message switching40.In (C) networks, the resources needed along a path to provide for c

25、ommunication between the end system are reserved for the duration of the communication session.A.packet-switched B.data-switchedC.circuit-switched D.message-switched41.In (A) networks, the resources are not reserved; a sessions messages use the resources on demand, and as a consequence, may have to

26、wait for access to communication link.A.packet-switched B.data-switchedC.circuit-switched D.message-switched42.In a circuit-switched network, if each link has n circuits, for each link used by the end-to-end connection, the connection gets (A) of the links bandwidth for the duration of the connectio

27、n.A.a fraction 1/n B.allC.1/2 D.n times43.For (C), 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.(B) means that the switch must receive the entire packet before it can begin to transmit the first

28、 bit of the packet onto the outbound link.A.Queuing delay B.Store-and-forward transmissionC.Packet loss D.Propagation45.The network that forwards packets according to host destination addresses is called (D) network.A.circuit-switched B.packet-switchedC.virtual-circuit D.datagram46.The network that

29、forwards packets according to virtual-circuit numbers is called (C) network.A.circuit-switched B.packet-switchedC.virtual-circuit D.datagram47.In the following entries, which is not a kind of access network? (D)A.residential access B.company accessC.wireless access D.local access48.Suppose there is

30、exactly one packet switch between a sending host 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-

31、end delay to send a packet of length L? (Ignore queuing delay, propagation delay, and processing delay.) (A)A.L/R1L/R2 B.L/R1C.L/R2 D.none of the above49.The time required to examine the packets header and determine where to direct the packet is part of the (B).A.queuing delay B.processing delayC.pr

32、opagation delay D.transmission delay50.The time required to propagate from the beginning of the link to the next router is (C).A.queuing delay B.processing delayC.propagation delay D.transmission delay51.Consider sending a packet of 3000bits over a path of 5 links. Each link transmits at 1000bps. Qu

33、euing delays, propagation delay and processing delay are negligible. (6 points)(1).Suppose the network is a packet-switched virtual circuit network. VC setup time is 0.1 seconds. Suppose the sending layers add a total of 500 bits of header to each packet. How long does it take to send the file from

34、source to destination?t=5*(3000+500)/1000+0.1=17.6s(2).Suppose the network is a packet-switched datagram network and a connectionless service is used. Now suppose each packet has 200 bits of header. How long does it take to send the file?t=5*(3000+200)/1000=16s(3).Suppose that the network is a circu

35、it-switched network. Further suppose that the transmission rate of the circuit between source and destination is 200bps. Assuming 0.02s setup time and 200 bits of header appended to the packet, how long does it take to send the packet?t=(3000+200)/200+0.02=16.02sChapter 2 Application Layer1.In the f

36、ollowing four descriptions, which one is correct? A.In C/S architecture, clients communicate with each other directly.B.In C/S architecture, client has a fixed well-known address.C.In P2P architecture, peers communicate with each other directly.D.In P2P architecture, peer has a fixed well-known addr

37、ess.2.In the context of a communication session between a pair of process, the process that initiates the communication is labeled as the , the process that waits to be contacted to begin the session is labeled as the .A.client process, server process B.sending process, receiving processC.input proc

38、ess, output process D.communicating process, connecting process3.A socket is the interface between within a host. A.the network layer and the link layerB.the link layer and the physical layerC.the application layer and the transport layerD.the transport layer and the network layer4.In the following

39、applications, which one is a loss-tolerant application? A.E-mail B.file transfer C.instant messaging D.real-time audio5.In the following applications, which one is a bandwidth-sensitive application? A.E-mail B.web application C.real-time audio D.file transfer6.The service of TCP cant guarantee .A.de

40、livery of all data without error B.delivery of all data in the proper orderC.the rate of delivery D.congestion control7.In the following applications, which one uses UDP? A.E-mail B.web application C.file transfer D.DNS8.In the following descriptions about HTTP, which one is not correct? A.HTTP uses

41、 non-persistent connections in its default mode.B.HTTP uses TCP as its underlying transport protocol.C.HTTP is a stateless protocol.D.HTTP is client-server architecture.9.Suppose a web page consists of a base HTML file,5 JEPG images and a java applet,and also suppose HTTP uses persistent connection

42、without pipelining,the total response time is .A.2RTT B.8RTT C.12 RTT D.14RTT10.In HTTP response message, if the requested HTTP protocol version is not supported, the status code is .A.200 B.301 C.400 D.50511.The port number of web application is .A.25 B.20 C.80 D.5312.A network entity that satisfie

43、s HTTP requests on the behalf of an origin web server is .A.server farm B.server stack C.proxy server D.edge server13.In the following descriptions about persistent connection, which one is not correct? A.The server leaves the TCP connection open after sending a response.B.Each TCP connection is clo

44、sed after the server sending one object.C.There are two versions of persistent connection: without pipelining and with pipelining.D.The default mode of HTTP uses persistent connection with pipelining.14.FTP uses two parallel TCP connections to transfer a file, there are .A.control connection and dat

45、a connectionB.receiving connection and sending connectionC.client connection and sever connectionD.program connection and process connection15.In the following descriptions about FTP, which one is correct?A.FTP is p2p architecture. B.FTP sends its control information out-of-band.C.FTP uses persisten

46、t connection. D.FTP is a stateless protocol.16.In the commands of FTP, which one does not have parameter? A.USER B.PASS C.LIST D.STOR17.The Internet mail system has three components which they are .A.user agent, SMTP, POP3 B.SMTP, POP3, IMAPC.user agent, SMTP, IMAP D.user agent, SMTP, mail server18.

47、If the status code in HTTP response message is 404, it means .A.Request succeeded. B.The requested document doesnt exit on this server.C.This is a generic error code indicating that the request could not be understood by the server.D.Requested object has been permanently mover.19.Comparison HTTP wit

48、h SMTP, the correct is .A.HTTP is a push protocol, and SMTP is a pull protocol.B.In the default mode, both of them use persistent connection.C.HTTP places all of the messages objects into one message, and SMTP sends every object one by one.D.HTTP requires each message to be in 7-bit ASCII format, an

49、d SMTP doesnt impose this restriction.20.The headers in the MIME message must include except .A.From B.Content-type C.Content-transfer-encoding D.MIME version21.In the following protocol, which one is stateless? A.POP3 B.SMTP C.FTP D.IMAP22.DNS means .A.Data Name System B.Data National SystemC.Domai

50、n Name System D.Domain National System23.There are three classes of DNS server except .A.Root DNS server B.Local DNS serverC.TLD server D.Authoritative DNS server24.DNS provides some services except .A.Host aliasing B.Mail server aliasingC.Load distribution D.A single point of failure25.There are three architectures for locating content in P2P file sharing, KaZaA uses .A.Centralized Direct