计算机网络卷附答案

1、东学2009 2010试 卷 （ A第 一 学期卷 ）学院学年课程名称：计算机网络（Computer Networks）班级. Multiple Choice（20 pos,1 po for each） Directions: Choose the correct answer for each question and fill ithe 学号 corresponding bl. There is ONLY ONE correct answer for each question.密 ()2According to the ISO/OSI reference m, the Ethernet

2、switch works on: A. Data link layerB. Network layerC. Transport layerD. Presenion layer 封 ()6When two computers communicate via a ephone line, which of the following device is nesary?线 ()8What many bytes are therehe payload of an ATM cell? ()9The core of theernet protocols is:()10With respect to pro

3、tocol layer, the ARP protocolCP/IP corresponds to:A. physical layerB. data link layerC. network layerD. transport layer ()11The lower layer of OSPF protocol uses:A. UDPB. TCPC. ARPD. IP()12Which port on sever does the POP3 protocol use?A. 20B. 23C. 25D. 110()13What is the mask for a smallest subnet

4、usable in practice?A. B. 54C. 52D. 55()14Which of the following IP address CANNOT be assigned to a host? A. 0/16B. 1/24C. 55/16D. 55/24()15When installing a MODEM to a PC, theerfatandard we take is:A. X.25B. RJ11C. RS232D. RJ45()16Which of the following is NOT an advantage of a layer m?Dividing the

5、complex network operationo a more manageable layer approach.Allowing changes to occur in one layer withouving to change all layers.Allowing changes to occur in all layers withouving to change one layer.Defining a standarderface for the plug-and-play multivendoregration. ()17How many bits are there f

6、or an Ethernet MAC address?A. 32B. 48C. 64D. 128()18The protocol for two computers to transport files is:A. FTPB. WWWC.netD. SMTP ()19Theernet can be traced back to its origin:A. ARPANETB. ALOHAC. NEFNETD. Ethernet()20Which of the following IPv6 address is correct?A. 2001:8:417AB. :0:0:0:0:0:F C. :9

7、D. 9:总分一二三四五A. IPX/SPXB. PPPC. TCP/IPD. SLIPA. 48B. 53C. 64D. 36A. network adapterB. MODEMC. repeaterD. coaxial cable()7If a package is to be broadcasted to the local network, then the destination IP address of the package should be:A. 55B. C. the lowest address of the subnetD. the highest address o

8、f the subnet()3 Which device extends the LAN on network layer?A. RepeaterB. HubC. SwitchD. Router()4How many network segments can be there at most for network connected by hubs?A. 5B. 4C. 3D. 2()510BaseT network takes:A. thick coaxial cable, bus topologyB. twisted pair, ring topologyC. thin coaxial

9、cable, star topologyD. twisted pair, star topology()1There are two kinds of coaxial cables usually used. One is the baseband cable and the other is the broadband cable. The impedance of the baseband cable is:A. 50B. 70C. 75D. 90学院 Directions: Fill proper contentso the bls according to the context.1T

10、he length of an IPv6 header is60bytes.1Make a comparison among the three networkerconnection devi: hubs, routers and班级2.The TCP/IP protocol consists of5(how many) layers.switches. Fill in “Yes” or “No”he bls of the following form to say whether the device 3 d will test the ernal loack of a computer.

11、 (Fill the can perform the corresponding function. (6 pos) completed with parameters)4._254_ (how many) usable subnets are created by applying the subnet mask学号 to a Class B network. 5.-is a Layer-2 broadcast address.密 6.The switching method t traditional ephone takes is circuit switching , while th

12、e methodt IPephone takes is packet switching . 7.The common used guided transmis media are_coaxial cable_, _twisted pair_, and _optical fiber_. . True or False （10 pos, 1 po for each）Consider the TCP/IP protocol suite:Fill the names of protocol data units corresponding to each layerDirections: Answe

13、r the following using T (True)/F (False). You do not need to explain your answers.he PDU com.(4 pos)(2) Match the following functions to one of the five layers s)he Function com. (10po (T)1 Carrier Sense Multiple Acs with Colli Detection usese, Reliable pros-to-pros message delivery-served approach.

14、Packet switchingDefines framesProvides user servi封(T) 2Ethernet provides unreliable, connectionless service.such asand file transfer (T) 3The feature of a Token Ring network is colliless environment.Transmisof bit stream across physical medium (F) 48 broadcasts are created when you segment a network

15、 win 8-port Mechanical, electronical, and functionalReassembly of data packetserfaceswitch.Ensure reliable transmisNetwork selectionRoute determinationof data(TT) 5Packet-switching networks place a tight upper limit on block size.) 6Network Address Translation technology is a solution to expand the

16、numberof IP addresses available for public use.(T) 7Latency through the store-and-forward switch varies with frame length.LayDUFunctions线 (F) 8Security is one of the advantages of using sic routes over dynamic routes. Application LayerMessage (F) 9OSPF is an er-AS routing protocol, whiGP is an ra-AS

17、 routing Transport LayerSegmentprotocol.Network Layacket (F) 10ime-Divi Multiplexing, each user cannot get all of the bandwidth Data Link LayerFrameperiodically during its slot.Physical LayerBits on the wireHubsRoutersSwitchesTraffic IsolationNoYesYesPlug & PlayYesNoYesOptimal RoutingNoYesNoCut Thro

18、ughYesNoYes. Fillhe Forms （20 pos） Directions: Fill proper contentso the forms. Fillhe Bls （10 pos, 1 po for each bl）3(6 po nodes) Use Dijkstra Algorithm to find out the shortest paths from origin E to every other1AC1224B2DE2Solution:EA: EA, cost(E,A)=4 EB: EDB, cost(E,B)=4 EC: EDC, cost(E,C)=4ED: E

19、D, cost(E,D)=2学 院. Comprehensive Calculation （40 pos）班 级1(5 pos) How long does it take to send a file of 640K bits from hoso host B over a circuit-switched network?All links are 1.536 Mbps学 号Each link uses TDM with 24 slots/sec密500 milliseconds to establish end-to-end circuit Solution:TransmisSpeed:

20、 1.536Mbps24=64Kbps TransmisTime: 640K64Kbps=10sConnection Establishment Time: 0.5s File sending time: 10.5s封 2.(5 pos) The distance betn host A and host B is L10000Km. The bandwidth of the link is R1Mbps (220 bps). Supe the propagation speed over this link is V2.5108m/s.What is the propagation time

21、 Tp?During this time, how many bits have been sent to the link by host A?What is the distance d betn two adjacent bits?Solution:TpLV0.04s NumbTpR=41943 dL Numb238m线.4(9 pos) Ananization is granted an IP address . The networkadministrator wants to create 32 subnets.Find out the subnet mask.Find out t

22、he number of host addresses in each subnet.(3) Find out the network address of thesubnet. he(4) Find out theand last host addressessubnet.(5) Find out the subnet directed broadcast address and limited broadcast address subnet.he密Solution:(1) 52(2) 2(3) (4) (5) 55封线5(15 pos) Consider a router with the following routing table:Destination Addresbnet MaskNex