通信网基本知识实验报告EthernetandARP

_实验一EthernetandARP格式的理解；1.CapturingandanalyzingEthernetframes2.TheAddressResolutionProtocol (一)CapturingandanalyzingEthernetframes_(1)BasedonthecontentsoftheEthernetframecontainingtheHTTPGETmessage1.Whatisthe48-bitEthernetaddressofyourcomputer?Answer：The48-bitEthernetaddressofmycomputeris:c8:0a:a9:db:9b:f32.Whatisthe48-bitdestinationaddressintheEthernetframe?IsthistheEthernetaddressof?(Hint:theanswerisno).WhatdevicehasthisasitsEthernet_address?[Note:thisisanimportantquestion,andonethatstudentssometimesgetwrong.Re-readpages468-469inthetextandmakesureyouunderstandtheanswerhere.]Answer：1)The48-bitdestinationaddressintheEthernetframeis:00:23:89:8d:50:712)ThisisnottheEthernetaddressof.3)ItistheaddressofmyLinksysrouter,whickisthelinkusedtogetoffthesubnet.3.Givethehexadecimalvalueforthetwo-byteFrametypefield.Whatdothebit(s)whosevalueis1meanwithintheflagfield?Answer：1)Thehexadecimalvalueforthetwo-byteFrametypefield_Thevalueiswithintheflagfieldmeansthefragmenthasnotbeenfragmented.4.HowmanybytesfromtheverystartoftheEthernetframedoestheASCII“G”in“GET”appearintheEthernetframe?Answer：1)TheASCII“G”appears54bytesfromtheverystartoftheEthernetframe._2)Calculationprocessasfollows:Thereare14bytesofEthernetframe,20bytesofIPheaderand20bytesofTCPheaderbeforeHTTPdataisencountered.5.WhatisthehexadecimalvalueoftheCRCfieldinthisEthernetframe?Answer：1)ThereisnoCRCfield.etsnifferstartup.(2)BasedonthecontentsoftheEthernetframecontainingthefirstbyteoftheHTTPresponsemessage6.WhatisthevalueoftheEthernetsourceaddress?Isthistheaddressofyourcomputer,orof(Hint:theanswerisno).WhatdevicehasthisasitsEthernetaddress?Answer：1)ThevalueoftheEthernetsourceaddressis:00:23:89:8d:50:71_2)Thisisneithertheaddressofyourcomputer,northeaddressof.ItistheaddressofmyLinksysrouter,whichisthelinkusedtogetontomysubnet.7.WhatisthedestinationaddressintheEthernetframe?IsthistheEthernetaddressofyourcomputer?Answer：1)ThedestinationaddressintheEthernetframeis:c8:0a:a9:db:9b:f32)Itistheaddressofmycomputer.(The48-bitEthernetaddressofmycomputeris:c8:0a:a9:db:9b:f3)_8.Givethehexadecimalvalueforthetwo-byteFrametypefield.Whatdothebit(s)whosevalueis1meanwithintheflagfield?Answer：1)Thehexadecimalvalueforthetwo-byteFrametypefieldis:0x0800.2)Thevalueis1withintheflagfieldmeansthefragmenthasnotbeenfragmented._9.HowmanybytesfromtheverystartoftheEthernetframedoestheASCII“O”in“OK”(i.e.,theHTTPresponsecode)appearintheEthernetframe?Answer：1)TheASCII“O”appears54bytesfromtheverystartoftheEthernetframe.2)Calculationprocessasfollows:Thereare14bytesofEthernetframe,20bytesofIPheaderand20bytesofTCPheaderbeforeHTTPdataisencountered.10.WhatisthehexadecimalvalueoftheCRCfieldinthisEthernetframe?Answer：1)ThereisnoCRCfield.2)Thereason:BecausetheCRCcalculatedbeforetheWiresharkpacketsnifferstartup.(二)TheAddressResolutionProtocol_ (1)ARPCaching11.Writedownthecontentsofyourcomputer’sARPcache.Whatisthemeaningofeachcolumnvalue?Answer：1)TheInternetAddresscolumncontainstheIPaddress,.2)ThePhysicalAddresscolumncontainstheMACaddress,andthetypeindicatestheprotocoltype.3)ObservingARPinaction_12.WhatarethehexadecimalvaluesforthesourceanddestinationaddressesintheEthernetframecontainingtheARPrequestmessage?Answer：1)ThehexadecimalvaluesforthesourceaddressesintheEthernetframecontainingtheARPrequestmessageis:00:23:89:8d:50:712)ThedestinationaddressesintheEthernetframecontainingtheARPrequestmessageis:ff:ff:ff:ff:ff:ff_13.Givethehexadecimalvalueforthetwo-byteEthernetFrametypefield.Whatdothebit(s)whosevalueis1meanwithintheflagfield?Answer：Thehexadecimalvalueforthetwo-byteEthernetFrametypefieldis:0x0806.14.DownloadtheARPspecificationfrom/innotes/std/std37.txt.Areadable,detaileddiscussionofARPisalsoathttp://www.erg.abdn.ac.uk/users/gorry/course/inets/a_rp.html.a)HowmanybytesfromtheverybeginningoftheEthernetframedoestheARPopcodefieldbegin?Answer：TheARPopcodefieldbegins20bytesfromtheverybeginningoftheEthernetframe.b)WhatisthevalueoftheopcodefieldwithintheARP-payloadpartoftheEthernetframeinwhichanARPrequestismade?oadoftherequestis1._c)DoestheARPmessagecontaintheIPsender?Answer：Yes,theARPmessagecontaing05forthesender.addressofthetheIPaddressd)WhereintheARPrequestdoesthe“question”appear–theEthernetaddressofthemachinewhosecorrespondingIPaddressisbeingqueried?00:00:00:00:00:00toquestionthemachinewhosecorrespondingIPaddress(05)isbeingqueried._15.NowfindtheARPreplythatwassentinresponsetotheARPrequest.a)HowmanybytesfromtheverybeginningoftheEthernetframedoestheARPopcodefieldbegin?Answer：TheARPopcodefieldbegins20bytesfromtheverybeginningoftheEthernetframe.b)WhatisthevalueoftheopcodefieldwithintheARP-payloadpartoftheEthernetframeinwhichanARPresponseismade?oadpartoftheEthernetframeis2．_c)WhereintheARPmessagedoesthe“answer”totheearlierARPrequestappear–theIPaddressofthemachinehavingtheEthernetaddresswhosecorrespondingIPaddressisbeingqueried?Answer：TheanswertotheearlierARPrequestappearsinthe”address00:d0:59:a9:3d:68forthesenderwithIPaddress.16.WhatarethehexadecimalvaluesforthesourceanddestinationaddressesintheEthernetframecontainingtheARPreplymessage?address._andforthedestinationis00:d0:59:a9:3d:68.17.Opentheethernet-ethereal-trace-1tracefileinHYPERLINK"/wireshark-l