1、1.1 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 two or more communicating entitiesC the actions taken on the transmission of a message or other eventD the tran
2、smission signals are digital signals or analog signals1.2 In the following options, which is defined in protocol? ( A )A the actions taken on the transmission and/or receipt of a message or other eventB the objects exchanged between communicating entitiesC the content in the exchanged messagesD the
3、location 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 control B congestion-controlC reliable data transfer D connection-oriented service1.4 The Internets connection-oriented service has
4、a name, it is ( A ).A TCP B UDPC TCP/IP D IP1.5 The Internets connectionless service is called ( B ).A TCP B UDPC TCP/IP D IP1.6 Which of the following nodes belongs to the network core?CA. a Web Server B. a Host with Win2003 ServerC. a Router with NAT service D. a Supernode on Skype Network 1.7 In
5、the Internet, the equivalent concept to end systems is ( )A.A hosts B serversC clients D routers1.8 In the Internet, end systems are connected together by ( C ).A copper wire B coaxial cableC communication links D fiber optics1.9 End systems access to the Internet through its (C ).A modems B protoco
6、lsC ISP D sockets1.10 In the following options, which belongs to the network core? ( B )A end systems B routersC clients D servers1.11 End systems, packet switches, and other pieces of the Internet, run ( D ) that control the sending and receiving of information within the Internet.A programs B proc
7、essesC applications D protocols1.12 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 applications1.13 The protocols of various layers are called ( A ).A the protocol stack B TCP/IPC ISP
8、D network protocol1.14 In the OSI reference model, the upper layers of the OSI model are, in correct orderDA Session, application, presentationB Session, presentation, applicationC Session, application, presentation, physicalD Application, presentation, session1.15 The lower layers of the OSI model
9、are, in correct orderDA physical, system, network, logicalB physical, logical, network, systemC physical, transport, network, data linkD physical, data link, network, transport1.16 The Internet Protocol (IP) generally corresponds to which OSI layer?AA Network (layer three)B Transport (layer four)C D
10、ata link (layer two)D Session (layer five)1.17 What layer of the OSI model is designed to perform error detection functions?BA PhysicalB Data linkC NetworkD transport1.18 Which of the following protocol layers is not explicitly part of the Internet Protocol Stack? _B_A. application layer B. session
11、layerC. data link layer D. transport layer1.19 The 5-PDU is called_A_A. message B. segment C. datagram D. frame1.20 The Internets network layer is responsible for moving network-layer packets known as B( ) from one host to another.A frame B datagramC segment D message1.21 Transport-layer packets are
12、 called:BA. message B. segment C. datagram D. frame1.22 The units of data exchanged by a link-layer protocol are called ( A).A Frames B SegmentsC Datagrams D bit streams1.23 There are two fundamental approaches to building a network core, ( B ) and packet switching.A electrical current switching B c
13、ircuit switchingC data switching D message switching1.24 Datagram networks and virtual-circuit networks differ in that ( 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-circ
14、uit 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
15、 destination.1.25 (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 TDM1.26 In ( C ) networks, the resources needed along a path to provide for c
16、ommunication between the end system are reserved for the duration of the communication session.A packet-switched B data-switchedC circuit-switched D message-switched1.27 In ( A ) networks, the resources are not reserved; a sessions messages use the resources on demand, and as a consequence, may have
17、 to wait for access to communication link.A packet-switched B data-switchedC circuit-switched D message-switched1.28 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 co
18、nnection.A a fraction 1/n B allC 1/2 D n times1.29 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 FDM1.30 The network that forwards packets according to host destination addresses is called (
19、D) network.A circuit-switched B packet-switchedC virtual-circuit D datagram1.31 The network that forwards packets according to virtual-circuit numbers is called ( C ) network.A circuit-switched B packet-switchedC virtual-circuit D datagram1.32 The time required to propagate from the beginning of the
20、 link to the next router is ( C).A queuing delay B processing delayC propagation delay D transmission delay1.33 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 pac
21、ket1.34 In the following four descriptions, which one is correct? ( C)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 traff
22、ic intensity is close to one, the average queuing delay will be close to one.1.35 Suppose, a is the average rate at which packets arrive at the queue, R is the transmission rate, and all packets consist of L bits, then the traffic intensity is ( B ),A LRa B LaRC RaL D LRa1.36 Suppose there is exactl
23、y 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-end de
24、lay to send a packet of length L? (Ignore queuing delay, propagation delay, and processing delay.) ( A )A L/R1L/R 2 B L/R1C L/R2 D 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 destination and the l
25、ink has a transmission rate of 10 Mbps. Assume that the propagation speed is 2 * 108 meters/sec, and the distance between source and destination is 10,000 km. Also suppose that message switching is used, with the message consisting of the entire MP3 file. How many bits will the source have transmitt
26、ed when the first bit arrives at the destination?CA. 1 bit B. 30,000,000 bits C. 500,000 bits D. none of the above1.38 In the following entries, which is not a kind of access network?(D )A residential access B company accessC wireless access D local access1.39 The following technologies may be used for residential access, exceptDA. HFC B. DSL C. Dial-up modem D. FDDI1.40 Which kind of media is not a guided media? ( D)A twisted-pair copper wire B a coaxial cableC fiber optics D digital satellite channel
