SSD8单选题文档格式.docx

SSD8单选题文档格式.docx

《SSD8单选题文档格式.docx》由会员分享，可在线阅读，更多相关《SSD8单选题文档格式.docx（57页珍藏版）》请在冰豆网上搜索。

（d）whatvendoryourInternetserviceproviderpurchasedequipmentfrom

4.Whichofthefollowingmethodsareinvokedbyaclientimplementedwithsockets?

（d）

Iconnect（）IIlisten（）IIIread（）

（a）IIIonly

（b）I,II,andIII

（c）Ionly

（d）IandIIIonly

5.Anadvantageofdefiningnetworkprotocolsthroughagreementamongmanycompaniesandindividualsisthat（c）

（a）onlyoneimplementationneedthenbecreated

（b）aprotocoldesignedbycommitteealwayshasbetterperformancethanthatdesignedbyasinglecompanyorresearchproject

（c）differentimplementationscanthencommunicatewitheachother

（d）otherwisesourcecodewouldneedtobeshippedwithallnetworkingapplications

（a）Itisunlikelytobetruethatoneimplementationcanworkwellinallplatformsandsituations,andevenifthisweretrue,standardizationwouldnotmakeitanymorepossible.

6.Whichofthefollowingmethodsareinvokedbyaserverimplementedwithsockets?

Iconnect（）IIlisten（）IIIaccept（）

（a）I,II,andIII

（b）IIIonly

（c）IIonly

（d）IIandIIIonly

7.Anapplicationonacomputersendsdatathroughasockettoanothercomputer.Whichofthefollowingarespecifiedbythecommunicationprotocol?

（a）

IThecontentsofthemessagebody

IIThespeedoftransmission

IIITheheaderformat,whichspecifiestheheaderfieldsizesandmeanings

（b）IIandIIIonly

（b）Thespeedoftransmissionmayaffectthecommunication,butitisnotspecifiedbytheprotocol.

8.Whichofthefollowingdistinguishstreamsockets（e.g.,TCP）fromdatagramsockets（e.g.,UDP）?

（b）

Streamsocketsguaranteedeliveryofthedatasentthroughthem.

Streamsocketscanbeusedtosendapplicationdatatoaremotehost,whereasdatagramsocketscanonlysendcontrolcommands.

Streamsocketshavegreateroverhead.

（a）IIandIIIonly

（b）IandIIIonly

（d）IandIIonly

9.Allstore-and-forwardnetworksare（d）

（a）connection-basednetworks

（b）broadcastnetworks

（c）connectionlessnetworks

（d）packetormessageswitchednetworks

10.Whichofthefollowingpairsofentitiesnameaclientandoneofitsservers?

（d）

Googlesearchengine/

Webbrowser/Googlesearchengine

Emailclient/Webbrowser

（c）Thesearchenginealsohastosearchotherservers.

11.Whydonetworkapplicationssend"

messages,"

butthenetworktransmitsinformationin"

packets?

"

（a）

（1）Bufferallocationanderrorhandlingiseasierwhendoneforsmallerchunksofdata.

（2）Multiplemessagescanbesentinasinglelargepackettodecreaseoverhead.

（3）Networkengineersandapplicationprogrammersjustusedifferentterminologyforthesameunitofapplicationdata.

（4）Amessageneedstobepackagedwiththeinstructionstoprocessitatthedestination.

（a）IandIIonly

（b）IIandIVonly

（c）I,II,III,andIV

12.WhichofthefollowingparameterscanbespecifiedintheheaderofarequestintheHypertextTransferProtocol（HTTP）?

（b）

（1）Thetypesofimageformatsthatabrowserunderstands

（2）Thetypeofbrowser（e.g.,Netscape,InternetExplorer）makingtherequest

（3）Themethodbywhichtherequestistobesatisfied—forexample,whethertherequestisaGETofaformsubmission

（c）IIIonly

13.Howdoesanoperatingsystemidentifytheapplicationtowhichdatacominginfromthenetworkshouldberelayed?

（a）Bytheprotocolwithwhichthedatawassent

（b）Bytheportnumbercarriedbythetransportprotocol

（c）Onlyoneapplicationatatimeisgivenaccesstothenetwork.

（d）Bythefileextensionofthedata

14.WhichofthefollowingarespecifiedbytheHTTPprotocol?

Thesyntaxoftherequestheader

Thesyntaxoftheresponseheader

Thespecificlegalnamesoftherequestheaderfields

（b）Ionly

（c）IandIIIonly

1.1.2

1.PacketcollisionsoccurinanEthernetnetworkbecause（a）

（a）twoEthernetnodescansendpacketsatthesametime

（b）theEthernetusesaringtopology

（c）twodifferentEthernetnetworksmaybesplicedtogether

（d）theEthernetswitchingmechanismmayoccasionallysendtwopacketsthroughthesameroute

2.PacketcollisionsoccurinanEthernetnetworkbecause（b）

（a）theEthernetswitchingmechanismmayoccasionallysendtwopacketsthroughthesameroute

（b）twoEthernetnodescansendpacketsatthesametime

（c）theEthernetusesaringtopology

（d）twodifferentEthernetnetworksmaybesplicedtogether

3.TwopacketsAandBaresentinthatorderthroughaconnectionlesscommunicationnetwork.Theywillarriveatthedestination（c）

（a）intheorderA-B,afterpossiblyhavingtraverseddifferentroutes

（b）inanyorder,afterhavingtraversedthesameroute

（c）inanyorder,afterpossiblyhavingtraverseddifferentroutes

（d）intheorderA-B,afterhavingtraversedthesameroute

1.1.4

1._____canbeusedtomeasurelatencyinthecommunicationnetwork.（d）

（a）BitErrorRate

（b）Percentageofpacketsretransmitted

（c）Throughput

（d）Roundtriptime

2.ApacketwithnodataissentfromhostAtohostBonanotherwiseidlenetwork.Thepacketisfoundtohavetaken35millisecondstoreachB.Theincrementaloverheadtosendanadditionalbyte（usuallycalledthe"

throughput"

）isestimatedtobefivemicrosecondsbyrepeatedlymeasuringthetransmissiontimesoflongpackets.Approximately,howlongwillaneightKbytes（8192bytes）packettaketoreachBwhensentfromA?

（a）76milliseconds

（b）cannotbedeterminedfromtheinformationgiven

（c）55milliseconds

（d）40milliseconds

3.Acomputersends100Kbytesofaggregatedatatoanothercomputerthroughthenetwork.Ifthistransmissiontimetakes10secondsandsetuptimeisnegligible,thethroughputofthisnetworkis（a）

（a）intherangefrom60to120Kbps（kilobitspersecond）

（b）intherangefrom6to12Kbps（kilobitspersecond）

（c）exactly10Kbps

（d）notabletobedeterminedwiththeinformationgiven

4.Thetransmissionofhigh-quality,interactivevoiceandvideooverthecurrentInternetisdifficultbecausetoday'

sInternet（c）

（a）usesconnectionlessprotocols

（b）giveshigherprioritytobulkdatatransfers

（c）isunabletoguaranteeminimumthroughputormaximumlatencyforagivenconnection

（d）doesnotreallyhavesufficientthroughput

5.ThethroughputofanetworklinkforanHTTPsessionismeasuredintwoways.MeasurementAisthetotalamountofdatareceivedbythebrowser,dividedbythedurationofthesession.MeasurementBisthetotalamountofdatareceivedbytheoperatingsystemonbehalfofthebrowser,dividedbythedurationofthesession.WhichofthefollowingstatementsaboutAandBistrue?

（c）

（a）BissmallerthanA

（b）BandAarenotrelated

（c）AissmallerthanB

（d）BisequaltoA

6.Acomputersends100Kbytesofaggregatedatatoanothercomputerthroughthenetwork.Ifthistransmissiontimetakes10secondsandsetuptimeisnegligible,thethroughputofthisnetworkis（b）

（a）intherangefrom6to12Kbps（kilobitspersecond）

（b）intherangefrom60to120Kbps（kilobitspersecond）

（c）notabletobedeterminedwiththeinformationgiven

（d）exactly10Kbps

7.WesendapacketfromhostAtohostB,whichimmediatelyacknowledgesit.WemeasuretheintervalbetweenthetimethepacketissentbyAanditsacknowledgementisreceived.Thisintervalisfoundtobe180milliseconds.WhatcanbesaidaboutthelatencyofthelinkfromAtoB?

（c）

（a）Itisexactly90ms.

（b）Itisexactly180ms.

（c）Itissmallerthan180ms.

（d）Itisgreaterthan180ms.

1.1.5

1.

（1）WhatcanbesaidabouttheprotocolusedbytheimplementationofthetransportlayerofanInternethost?

Itguaranteesdelivery.

ItistheTransmissionControlProtocol（TCP）.

Itusesservicesprovidedbythesessionlayer.

（a）Ionly

（c）IandIIonly

（d）none

（2）WhatcanbesaidconcerningtheprotocolthatisusedbytheimplementationofthenetworklayerofanInternethost?

ItistheInternetProtocol（IP）.

（a）Ionly

（b）IIonly

2.WhatcanbesaidabouttheprotocolusedbytheimplementationofthetransportlayerofanInternethost?

（b）none

3.EveryProtocolDataUnit（PDU）thatissentbyaprotocollayertoitsremotepeeronthedestinationsystem