(完整版)川大软院计网选择题答案Chapter1(含答案)

1、1.1 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 en titiesB the order of messages excha nged betwee n two or more com muni cati ng en titiesC the actions take n on the tran smissi on of a message or other e

2、ve 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 message or other eve nt B the objects excha nged betwee n com muni cati ng en titiesC the conte

3、nt 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 and in 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

4、In ternet s conn eotiented service has a n ame, it is ( A ).A TCPB UDPC TCP/IPD IP1.5 The In ternet s 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

5、 Super node on Skype Network1.7 In the Intern et, the equivale nt con cept to end systems is ( )A.A hostsB serversCclie ntsD routers1.8 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 Inter

6、net through its (C ).A modemsB protocolsC 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 con trol the sending and recei ving of in formati

7、o n within the In ternet.A programsB processesCapplicati onsD protocols1.12 The internet allows ( D ) running on its end systems to exchange data with each other.A clie nts applicati onsBserver applicati onsC P2P applicati onsD distributed applicati ons1.13 The protocols of various layers are called

8、 ( A ).A the protocol stackB TCP/IPC ISPD n etwork protocol1.14 In the OSI reference model, the upper layers of the OSI model are, in correct orderDA Sessi on, applicati on, prese ntati onB Session, presentation, applicationC Session, application, presentation, physicalD Application, presentation, s

9、ession1.15 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 which OSI

10、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 explicitly p

11、art 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 AA. 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( ) from one host to ano th

12、er.A frameB datagram C segme ntD message1.21Tran 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 FramesB Segme nts C Datagrams D bit streams1.23 There are two fun dame ntal approachesto buildi ng a

13、 n etwork core, ( B ) and packet switch ing.A electrical curre nt switch ingB circuit switch ingC data switch ingD message switchi ng1.24 Datagram networks and virtual-circuit networks differ in that ( C ).A datagram n etworks are circuit-switched n etworks, and virtual-circuit n etworks are packet-

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

15、C. numbers and virtual-circuit networks use desti nati on addresses to forward 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 first bit of the packet onto the outbound link.A Store-a nd-forward tran smissi onB F

16、DMCEn d-to-e nd conn ecti onD TDM1.26 In ( C ) n etworks, the resources n eeded along a path to provide for com muni cati on betwee n the end system are reserved for the duratio n of the com muni cati on sessi on.A packet-switchedB data-switchedC circuit-switchedD message-switched1.27 In ( A ) netwo

17、rks, the resources 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 hasn circuits, for e

18、ach link used by the end-to-end connection, the connection gets ( A) th e link s bandwidth for the duration of the connection.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 of bits in a slot.A CDMAB packet-

19、switched n etworkC 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 network that forwards packets according to virtual-circuit numbers is called (C ) network.A circuit-s

20、witchedB 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 packe

21、t s headerB wait to tran smit the packet onto the linkCdeterm 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 int

22、en sity 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

23、 rate, and all 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 betwee n a sending host and a recei ving host. The tran smissi on rates betwee n the sending host and the switch and betwee n the switch and the

24、recei ving host arRi and R2, respectively. Assu ming that the switch uses store-a nd-forward packet switchi ng, what is the total en d-to-e nd delay to send a packet of len gth L? (Ig nore queu ing delay, propagati on delay, 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 only one link between source and destin