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1、ComputernetowrksLabsComputernetowrksLabsDNS,DataEncapsulationandFrameExaminationDNS,DataEncapsulationandFrameExaminationLearningObjectivesAtcompletionofthislab,youwillbeableto:1.UseWiresharktocaptureandanalyzeDNSmessage2.UnderstandhowDNSworks3.usenslookupandipconfigcommands 4.Explaintheh
2、eaderfieldsinanEthernetIIframe.5.understanddataencapsulation10ComputernetowrksLabs6.ReportandFeedbackonthislabAnswerallquestionswithsupportingscreenshots.Pleasefillinthefollowingfeedbackformandappendittothereport.Yourfeedbackisvaluabletoussothatwecanimprovethislab,andmakethecoursewelcome
3、.Foreachtask,pleaseratethefollowinginthescaleof1through5:·Thedegreeofdifficulty:1=tooeasy;5=toodifficult·Thelearningexperience:1=learnednothing;5=learnedalot·Yourinterest:1=nointerest;5=highinterest·Timeusedforthetask:inminutesTaskDifficulty(1—5)Learning(1—5)Interest(1—5)Time(min)Task0Ta
4、sk1Task2Task3Task4Yoursuggestion/comment:BackgroundWhenupperlayerprotocolscommunicatewitheachother,dataatthesendinghost flowsdowntheTCP/IPprotocollayersandisencapsulatedintoaprotocoldataunitatlowerlayer,andfinallyencapsulatedinaLayer2frame.Forexample,DNSmessageisoftentransportedbyUDPprot
5、ocolonlayer4.SoDNSmessageatthesendinghostisencapsulatedinaUDPsegment; theUDPsegmentisthenencapsulatedinanIPpacket,andtheIPpacketisencapsulatedfinallyinalayer2frame.Theframecompositionisdependentonthemediaaccesstype,orthenetwork.Forexample,ifthemediaaccessisEthernet,thentheLayer2frameenca
6、psulationwillbeEthernetII.Whenlearningaboutdataencapsulationandprotocoloperations,itishelpfultoanalyzetheheaderinformationfoundintheprotocoldataunits.TheDNSprotocoloperation,ipconfigcommand,andEthernetIIframeheaderwillbeexaminedinthislab.EthernetIIframescansupportvariousupperlayerprotoco
7、ls.Formorebackgroundinformation,pleasereadthelectures02,04-05,10,11.10ComputernetowrksLabsTasksTask0 ProtocolLayersandDataEncapsulationAswehavediscussedinLecture02,Internetisinter-connectednetworksbasedonTCP/IPprotocols.Readtheslidesortextbooktolearnhowdatagoesthroughprot
