工业计算机网络作业.docx

工业计算机网络作业.docx

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工业计算机网络课后作业

第一次作业：

1.WhatisInternet?

Internetisaglobalnetworkconnectionfromthecomputerbyusingthecommonlanguagetocommunicatewitheachother.Onceyouconnecttoanynode,itmeansthatyourcomputerhasbeenconnected to theInternetonline.CurrentusersoftheInternethasbeenallovertheworld,therearemorethanhundredsofmillionsofpeopleusingtheInternet,andthenumberofusersisstillrisingingeometricprogression.

different

entitiesin

standardsorconventions.Forcommunicationbetween

exchangenetworkestablishedrules,

Data

2.WhatisaProtocol?

systems.Two entitiesin order tocommunicate,there must beofthe same

language,"and, forthe content of communications,howcommunicationandwhencommunicationmustcomplywithcertainrequirements,theseprovisionsisanagreement.Canalsobesimplydefinedas:

asetofrulestocontroldataexchangebetweenthetwoentities.Theconnectionofelectronic

communication,differentlevelshave their ownprotocol.For example,

inthehardwareleveland application-leveldataexchangehas its

ownprotocol.IntheOpen SystemsInterconnection

（OSI）standardmodel,eachlayerhasone totwo

protocols,thecommunicationterminalmustbeabletorecognizeandabidebytheagreement.Theprotocolhasbeendescribedoftenintheformofindustrialorinternationalstandards.

3.TheNetworkEdg

EDGistheEnhancedDataRatesforGSMEvolution.EDGisaGSMto3Gtransition,it

ismainlyusedintheGSMsystem,anewmodulationmethod,thatisthemost

advancedmulti-slotoperation and8PSK modulation.8PSKGMSK

modulationsignalspaceusedbytheexistingGSMnetworkcanbeextendedfrom2to

8,sotheinformationcontainedineachsymbolisfourtimestheoriginal.

第二次作业：

1.PleasecomparethedifferencebetweentheCircuitSwitchingandPacket

switching.

Circuitswitchingisthemostbackwardexchangemustfirstestablishacircuitconnection（virtualcircuit）,andthenfordataexchange,dataexchangeafterthereleasecircuit.In this

wayexchangeisrelativelyreliable,buttheefficiencyofnetworkutilizationisverylow.Generallydonotusethisexchange.

Packetswitchingisthemostcommonwayofexchange,itisadatagramintoseveralfragments,andthenweresentsimultaneously,eachpieceofdatathroughthelineroutingisnotthesame,eachpieceofdatatogoroutingaccordingtothespecificcircumstancesofthenetworkanduseroutingprotocolsto decide.Toreachthedestination node,thenall thedatafragmentsandre-assembled.Linehighefficiencyintheuseofthisexchange.

VCis also

known

asvirtual

connectionorvirtualchannelisatwopacket-

switchedtransmission.Communications andnetworks,theVCisaconnection-

orientedcommunication servicesprovidedbythepacket-

switchedcommunications.Establishalogicalconnectionorvirtual

circuitbetweentwo nodesor applicationprocess,you canturnbetweentwo

nodessendeachgrouping,to accepttheclient

receivesthepacketsequencemustbeconsistentwiththeorderofthe sending

end,not

responsible

forthe receiving

endinthecollectionofpacketreordering.VCprotocoltothehigher layer

protocolstohidedataisdividedintosegments,theprocessofpacketsorframes.

2.Pleasegavesomeexamplesofvirtualcircuitnetwork,istheInternetisoneoftheVCnetwork?

3.Whatisaccessnetwork,whatkindofaccessnetworkismostusedintheuniversitiesintheworld?

Withthecommunicationtechnologyistherapiddevelopmentoftelecommunication

servicestothedevelopmentofintegrated,digital,intelligent,broadbandandpersonaldirection,

realizationofvoice,data,image,"oneline,thefirst-linehouseholds,"laidthefoundation.Howtofullyutilizetheexistingnetworkresourcestoincreasethetypeofbusiness,improveservicequality,hasbecomethetelecomexperts

andoperatorsareincreasinglyconcernedabouttheresearchtopic,the"lastmile"solutionisthefocusofmostconcern.Therefore,theaccess

networktobecomethehotspotofnetworkapplicationsandconstruction.

4.Pleasecomparethedifferencebetweenbasebandcoaxialcableandbroadbandcoaxialcable

Basebandcoaxialcable,coaxialcabletothehardcoppercore,outsourcingalayerofinsulatingmaterial.Thislayerofinsulatingmaterialclosely

wovenmeshconductorsurround-network,coveringalayerof

protectivematerial.Therearetwowidelyusedcoaxialcable.A50ohmcablefordigitaltransmission,usedforbasebandtransmission,alsocalledbasebandcoaxialcable;theotheris75ohmcableforanalogtransmission,broadbandcoaxialcable.Thisdifferenceiscausedbyhistoricalreasons,andnotduetotechnicalreasonsormanufacturer.

Coaxialcableofthisstructure,ithashighbandwidthandexcellentnoiserejectioncharacte