川大软院计网选择题答案Chapter1含答案

1、1/ 71.1 In the following options, which does not define in protocol? ( D )A the format of messagesexcha nged betwee n two or more com muni cati ng entitiesB the order of messagesexcha nged betwee n two or more com muni cat ing entitiesC the actions take n on the tran smissi on of a message or other

2、eve ntD the tran smissi on sig nals are digital sig nals or an alog sig nals1.2 In the following options, which is defined in protocol? ( A )A the acti ons take n on the tran smissi on an d/or receipt of a messageor other eventB the objects excha nged betwee n com muni cati ng en titiesC the content

3、 in the excha nged messagesD the locatio n of the hosts1.3 An application can rely on the connection to deliver all of its data without error andin the proper order. The sentence describes (C ).A flow con trolB con gesti on-con trolC reliable data tran sferD conn ecti on-orie nted service1.4 The In

4、ternets conn eotiented service has a n ame, it is ( A ).A TCPB UDPC TCP/IPD IP1.5 The In ternets connectionl ess service is cBied (A TCPB UDPC TCP/IPD IP1.6 Which of the followi ng no des bel ongs to the n etwork core?CA. a Web ServerB. a Host with Win2003 ServerC. a Router with NAT serviceD. a Supe

5、r node on Skype Network1.7 In the Intern et, the equivale nt con cept to end systems is ( )A. A hostsB serversC clie ntsD routers2/ 71.8 In the Intern et, end systems are conn ected together by ( C ).A copper wireB coaxial cableC com muni catio n linksD fiber optics1.9 End systems access to the Inte

6、rnet through its (C ).A modems B protocols C ISPD sockets1.10 In the following options, which belongs to the network core? ( B )A end systemsB routersC clie ntsD servers1.11 End systems, packet switches, and other pieces of the Intern et, run ( D ) that control the sending and recei ving of in forma

7、tio n within the In ternet.A programsB processesCapplicati onsD protocols1.12 The internet allows ( D ) running on its end systems to exchange data with eachother.A clie nts applicati ons B server applicati ons C P2P applicati onsD distributed applicati ons1.13 The protocols of various layers are ca

8、lled ( A ).A the protocol stack B TCP/IPC ISPD n etwork protocol1.14 In the OSI reference model, the upper layers of the OSI model are, in correctorderDA Sessi on, applicati on, prese ntati onB Session, presentation, applicationC Session, application, presentation, physical D Application, presentati

9、on,session3/ 71.15 The lower layers of the OSI model are, i n correct orderDA physical, system, n etwork, logical B physical, logical, n etwork, systemC physical, tran sport, n etwork, data link D physical, data link, n etwork, tran sport1.16 The In ternet Protocol (IP) gen erally correspo nds to wh

10、ich OSI layer?AA Network (layer three) B Tran sport (layer four) C Data link (layer two) D Sessi on(layer five)1.17 What layer of the OSI model is desig ned to perform error detect ion fun cti ons?BA Physical B Data link C Network D tran sport1.18 Which of the followi ng protocol layers is not expli

11、citly part of the In ternet Protocol Stack?BA. applicatio n layerB. sessi on layerC. data link layerD. tran sport layer1.19 The 5-PDU is called_A_A. messageB. segme ntC. datagramD. frame1.20 The In ternet network layer is resp on sible for movi ng n etwork-layer packets known as B( ) fromone host to

12、 ano ther.A frameB datagramC segme ntD message1.21 Tran sport-layer packets are called:BA. messageB. segme ntC. datagramD. frame1.22 The un its of data excha nged by a lin k-layer protocol are called ( A).A FramesBSegme ntsC DatagramsD bit streams1.23 There are two fun dame ntal approachesto buildi

13、ng a n etwork core, ( B ) and packet switch ing.A electrical curre nt switch ingB circuit switch ingC data switch ingD message switchi ng4/ 71.24 Datagram networks and virtual-circuit networks differ in that ( C ).Adatagram networks are circuit-switchednetworks,and virtual-circuitn etworks are packe

14、t-switched n etworks.Bdatagramnetworks are packet-switchednetworks,and virtual-circuitn etworks are circuit-switched n etworks.C datagram n etworks use dest in ati on addresses and virtual-circuit n etworks useVC. nu mbers to forward packets toward their desti natio n.D datagram networks use VC. num

15、bers and virtual-circuit networks use desti nati on addresses toforward packets toward their desti nati on.1.25 (A ) means that the switch must receive the en tire packet before it can beg in to transmit the firstbit of the packet onto the outbound link.A Store-a nd-forward tran smissi onB FDMCEn d-

16、to-e nd conn ecti onD TDM1.26 In ( C ) networks, the resources needed along a path to provide for com muni cati on betwee n theend system are reserved for the durati on of the com muni cati on sessi on.A packet-switchedB data-switchedC circuit-switchedD message-switched1.27 In ( A ) networks, the re

17、sources are not reserved; a session s messages use theresources on dema nd, and as a con seque nee, may have to wait for access tocom muni cati on link.A packet-switchedB data-switchedC circuit-switchedD message-switched1.28 In a circuit-switched network, if each link has n circuits, for each link u

18、sed bythe end-to-end connection, the connection gets ( A) of the links bandwidth for the durati on of theconnection.A a fractio n 1/nB allC 1/2D n times1.29 For (C ), the tran smissi on rate of a circuit is equal to the frame rate multiplied by the nu mber ofbits in a slot.A CDMAB packet-switched n

19、etwork5/ 7C TDMD FDM1.30 The network that forwards packets according to host destination addressesis called ( D) network.A circuit-switchedB packet-switchedC virtual-circuitD datagram1.31 The n etwork that forwards packets accord ing to virtual-circuit nu mbers is called(C ) network.A circuit-switch

20、edB packet-switchedC virtual-circuitD datagram1.32 The time required to propagate from the beg inning of the link to the next router is ( C).A queu ing delayB process ing delayC propagati on delayD tran smissi on delay1.33 Process ing delay does not in clude the time to (B ).A examine the packets he

21、ader B wait to tran smit the packet onto the link Cdeterm ine where to direct the packetD check bit-error in the packet1.34 In the following four descriptions, which one is correct? ( C)A The traffic inten sity must be greater tha n 1.B The fracti on of lost packets in creases as the traffic inten s

22、ity decreases.C If the traffic inten sity is close to zero, the average queu ing delay will be close to zero.D If the traffic inten sity is close to one, the average queu ing delay will be close to one.1.35 Supposea is the average rate at which packets arrive at the queue,R is the tran smissi on rat

23、e, andall packets con sist cL bits, the n the traffic inten sity is ( B ),A LR/aB La/RC Ra/LD LR/a1.36 Suppose there is exactly one packet switch between a sending host and a recei ving host. Thetran smissi on rates betwee n the sending host and the switch and betwee n the switch and the recei6/ 7vi

24、ng host areRiand R2, respectively. Assu ming that the switch uses store-a nd-forward packet switching, what is the total en d-to-e nd delay to send a packet of length L? (Ignore queuing delay, propagationdelay, and process ing delay.) ( A )A L/R1+L/R2B L/RiC L/R2D none of the above1.37 We are sending a 30 Mbit MP3 file from a source host to a destination host. Suppose there is onlyone link between source and destination an