计算机网络英文题库(共4页).doc

精选优质文档-倾情为你奉上Chapter 1 Computer Networks and the Internet1The ( ) is a worldwide computer network, that is, a network that interconnects millions of computing devices throughout the world. ppt3Apublic Internet BIntranetCswitch net Dtelevision net2Which kind of media is not a guided media? ( )Atwisted-pair copper wire Ba coaxial cableCfiber optics Ddigital satellite channel3Which kind of media is a guided media? ( )Ageostationary satellite Blow-altitude satelliteCfiber optics Dwireless LAN4The units of data exchanged by a link-layer protocol are called ( ).AFrames BSegmentsCDatagrams Dbit streams5Which of the following option belongs to the circuit-switched networks? ( )AFDM BTDMCVC networks Dboth A and B6( )makes sure that neither side of a connection overwhelms the other side by sending too many packets too fast.AReliable data transfer BFlow controlCCongestion control DHandshaking 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.AStore-and-forward transmission BFDMCEnd-to-end connection DTDM8Datagram networks and virtual-circuit networks differ in that ( ).Adatagram networks are circuit-switched networks, and virtual-circuit networks are packet-switched networks.Bdatagram networks are packet-switched networks, and virtual-circuit networks are circuit-switched networks.Cdatagram networks use destination addresses and virtual-circuit networks use VC. numbers to forward packets toward their destination.Ddatagram 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? ( )Atwisted-pair wire Bfiber opticsCcoaxial cable Dsatellite10Processing delay does not include the time to ( ).Aexamine the packets headerBwait to transmit the packet onto the linkCdetermine where to direct the packetDcheck bit-error in the packet11In the following four descriptions, which one is correct? ( )AThe traffic intensity must be greater than 1.BThe fraction of lost packets increases as the traffic intensity decreases.CIf the traffic intensity is close to zero, the average queuing delay will be close to zero.DIf the traffic intensity is close to one, the average queuing delay will be close to one.12The Internets network layer is responsible for moving network-layer packets known as ( ) from one host to another.Aframe BdatagramCsegment Dmessage13The protocols of various layers are called ( ).Athe protocol stack BTCP/IPCISP Dnetwork protocol14There are two classes of packet-switched networks: ( ) networks and virtual-circuit networks.Adatagram Bcircuit-switchedCtelevision Dtelephone15Access networks can be loosely classified into three categories: residential access, company access and ( ) access.Acabled BwirelessCcampus Dcity areaQuestion 1617Suppose, 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 ( 16 ), and it should no greater than ( 17 ).16 ALRa BLaRCRaL DLRa17A2 B1C0 D-118In the Internet, the equivalent concept to end systems is ( ).Ahosts BserversCclients Drouters19In the Internet, end systems are connected together by ( ).Acopper wire Bcoaxial cableCcommunication links Dfiber optics20End systems access to the Internet through its ( ).Amodems BprotocolsCISP Dsockets21End systems, packet switches, and other pieces of the Internet, run ( ) that control the sending and receiving of information within the Internet.Aprograms BprocessesCapplications Dprotocols22There 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 are often referred to as ( ).Ainternets BLANCintranets DWAN23The internet allows ( ) running on its end systems to exchange data with each other.Aclients applications Bserver applicationsCP2P applications Ddistributed applications24The Internet provides two services to its distributed applications: a connectionless unreliable service and () service.Aflow control Bconnection-oriented reliableCcongestion control DTCP25It 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 a message or other event. The sentence describes ( ).AInternet BprotocolCintranet Dnetwork26In the following options, which does not define in protocol? ( )Athe format of messages exchanged between two or more communicating entitiesBthe order of messages exchanged between two or more communicating entitiesCthe actions taken on the transmission of a message or other eventDthe transmission signals are digital signals or analog signals27In the following options, which is defined in protocol? ( ) Athe actions taken on the transmission and/or receipt of a message or other event Bthe objects exchanged between communicating entities Cthe content in the exchanged messages Dthe location of the hosts28In the following options, which does not belong to the network edge? ( )Aend systems BroutersCclients Dservers29In the following options, which belongs to the network core? ( )Aend systems BroutersCclients Dservers30In the following options, which is not the bundled with the Internets connection-oriented service? ( )Areliable data transfer Bguarantee of the transmission timeCflow control Dcongestion-control31An application can rely on the connection to deliver all of its data without error and in the proper order. The sentence describes ( ).Aflow control Bcongestion-controlCreliable data transfer Dconnection-oriented service32It makes sure that neither side of a connection overwhelms the other side by sending too many packets too fast. The sentence describes ( ).Aflow control Bcongestion-controlCconnection-oriented service Dreliable 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 ( ).Aflow control Bcongestion-controlCconnection-oriented service Dreliable data transfer34The Internets connection-oriented service has a name, it is ( ).ATCP BUDPCTCP/IP DIP35In the following options, which service does not be provided to an application by TCP?( )Areliable transport Bflow controlCvideo conferencing Dcongestion control36The Internets connectionless service is called ( ).ATCP BUDPCTCP/IP DIP37In the following options, which does not use TCP?( )ASMTP Binternet telephoneCFTP DHTTP38In the following options, which does not use UDP?( )AInternet phone Bvideo conferencingCstreaming multimedia Dtelnet39There are two fundamental approaches to building a network core, ( ) and packet switching.Aelectrical current switching Bcircuit switchingCdata switching Dmessage switching40In ( ) networks, the resources needed along a path to provide for communication between the end system are reserved for the duration of the communication session.Apacket-switched Bdata-switchedCcircuit-switched Dmessage-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.Apacket-switched Bdata-switchedCcircuit-switched Dmessage-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.Aa fraction 1/n BallC1/2 Dn times43For ( ), the transmission rate of a circuit is equal to the frame rate multiplied by the number of bits in a slot.ACDMA Bpacket-switched networkCTDM DFDM44( ) 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.AQueuing delay BStore-and-forward transmissionCPacket loss DPropagation45The network that forwards packets according to host destination addresses is called ( ) network.Acircuit-switched Bpacket-switchedCvirtual-circuit Ddatagram46The network that forwards packets according to virtual-circuit numbers is called ( ) network.Acircuit-switched Bpacket-switchedCvirtual-circuit Ddatagram47In the following entries, which is not a kind of access network?( )Aresidential access Bcompany accessCwireless access Dlocal access48Suppose there is 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-end delay to send a packet of length L? (Ignore queuing delay, propagation delay, and processing delay.) ( )AL/R1L/R2 BL/R1CL/R2 Dnone of the above49The time required to examine the packets header and determine where to direct the packet is part of the ( ).Aqueuing delay Bprocessing delayCpropagation delay Dtransmission delay50The time required to propagate from the beginning of the link to the next router is ( ).Aqueuing delay Bprocessing delayCpropagation delay Dtransmission delay51Consider sending a packet of 3000bits over a path of 5 links. Each link transmits at 1000bps. Queuing 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 source to destination?(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?(3).Suppose that the network is a circuit-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?Solution: (1). t=5*(3000+500)/1000+0.1=17.6s   (2). t=5*(3000+200)/1000=16s   (3). t=(3000+200)/200+0.02=16.02s  专心-专注-专业