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1、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.Apublic Internet BIntranetCswitch net Dtelevision net2Which kind of media is not a guided media? ( )Atwisted-pai
2、r 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 streams5Wh
3、ich of the following option belongs to the circuit-switched networks? ( )AFDM BTDMCVC networks Dboth A and B6( ) 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 con
4、nection DTDM7Processing 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 packet8The Internets network layer is responsible for moving network-layer packets known as ( ) from one ho
5、st to another.Aframe BdatagramCsegment Dmessage9Access networks can be loosely classified into three categories: residential access, company access and ( ) access.Acabled BwirelessCcampus Dcity areaQuestion 1011Suppose, a is the average rate at which packets arrive at the queue, R is the transmissio
6、n rate, and all packets consist of L bits, then the traffic intensity is ( 16 ), and it should no greater than ( 17 ).10 ALRa BLaRCRaL DLRa11A2 B1C0 D112In the Internet, end systems are connected together by ( ).Acopper wire Bcoaxial cableCcommunication links Dfiber optics13End systems access to the
7、 Internet through its ( ).Amodems BprotocolsCISP Dsockets14End systems, packet switches, and other pieces of the Internet, run ( ) that control the sending and receiving of information within the Internet.Aprograms BprocessesCapplications Dprotocols15( ) defines the format and the order of messages
8、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.AInternet BprotocolCintranet Dnetwork16In the following options, which does not belong to the network edge? ( )Aend systems BroutersCclients Dservers17In
9、the following options, which belongs to the network core? ( )Aend systems BroutersCclients Dservers18There are two fundamental approaches to building a network core, ( ) and packet switching.Aelectrical current switching Bcircuit switchingCdata switching Dmessage switching19In ( ) networks, the reso
10、urces 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-switched20In ( ) networks, the resources are not reserved; a sessions messages use the resources on deman
11、d, and as a consequence, may have to wait for access to communication link.Apacket-switched Bdata-switchedCcircuit-switched Dmessage-switched21In 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 f
12、or the duration of the connection.Aa fraction 1/n BallC1/2 Dn times22( ) 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 DPropagation23The time required
13、to examine the packets header and determine where to direct the packet is part of the ( ).Aqueuing delay Bprocessing delayCpropagation delay Dtransmission delay24The time required to propagate from the beginning of the link to the next router is ( ).Aqueuing delay Bprocessing delayCpropagation delay
14、 Dtransmission delay25. In the four following options, which application is not C/S architecture?A. DNS B. Web application C. p2p file sharing D. E-mail26.The PDU of application layer is called ( ).A. message B. segment C. datagram D. frame27、The units of data exchanged by an Internets transport lay
15、er protocol are called( ). A. Frames B. Segments C. Datagrams D. bit streams 28Consider 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. (1).Suppose the network is a packet-switched datagram ne
16、twork and a connectionless service is used. Now suppose each packet has 200 bits of header. How long does it take to send the file?(2).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?Answers:15 ADCAD610 ABBBB 1115BCCDB 1620BBBCA 2125ABBCC 2627AB 28. Solution: (1). t=5*(3000+200)/1000=16s (2). t=(3000+200)/200+0.02=16.02s 专心-专注-专业