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计算机双语结业论文作者：吴迪学号：0807240538院系：自动化工程学院专业：自动化题目：WANanditsapplicationinintelligentbuildings指导者：陈东淼评阅者：陈东淼2011-12吉林TitleWANanditsapplicationinintelligentbuildingsAbstractipsecVPNandsslVPNaretwodifferenttechniques,canachievelargeamountsofdataremoteaccess,providingpeoplewithalowoperatingcost,highproductionefficiencyofremoteaccessmethods,accordingtothedifferentcharacteristicsofbusiness,chooseadifferentVPNtechnologies,makegooduseVPN,thecommunicationefficiencyforbusinesses,businessrunninggreatupgrade.Intelligentbuildingsrequireintegrationofavarietyofcomputer-basedbuildingautomationandcontrolsystemproductsthatareusuallymadebydifferentmanufacturers.BACnetTMisastandardcommunicationprotocolforBuildingAutomationandControlNetworksdevelopedbytheAmericanSocietyofHeating,RefrigeratingandAir-ConditioningEngineers(ASHRAE)[1].BACnetprovidesthecommunicationinfrastructureneededtointegrateproductsmadebydifferentvendorsandtointegratebuildingservicesthatarenowindependent.ThispaperdescribesthemainfeaturesoftheBACnetprotocolandearlyexperienceimplementingit.ThispaperdescribesthetechnicalsummaryofWAN,anditsapplicationBACnet.Keywords:WAN,buildingautomationandcontrolnetwork,intelligentbuildings,directdigitalcontrol,BACnet.Comments1.1ThetechnologyofWAN1.2ThecompositionandcharacteristicsofWAN1.3WAN-relatedtechnicalissues1.4PointtoPointConnection1.5Circuit-switched1.6WANPort1.7Firewall2.1Routerandroutings2.2Theroleofrouter2.3Theshortestpath2.4RoutingAlgorithm——Dijkstraalgorithm3.1TheHistoryofBACnetTMDevelopment3.2ATechnicalOverviewofBACnet3.3BACnetApplicationLayer3.4ApplicationServicesChapterOneSummaryofWAN1.1ThetechnologyofWANWAN(WideAreaNetwork)-WideAreaNetwork,iscurrentlyadivisionofthenetwork,thenetworkdivisionofthemostcommonisbasedonthescopeandroleofthenetworkinterconnectionbetweencomputersintothedistance,thereareWAN,LANandMANthreetypes.Suchanetwork,thelargestofitsscope,coveringawiderscopethanmetro(MAN)wider,whichisusuallyindifferentcitiesoftheLANorMANnetworkbetweentheInternet,canbetensofkilometerstotensofthousandsofkilometers.Theestablishmentofnationalorinternationalnetworksarewideareanetworks.Withinthewideareanetworkforcommunicationstransmissiondevicesandtransmissionmediacanbethetelecommunicationssector.Atpresent,theworld'slargestinformationnetworkInternethasbeencovered,includingmyownmorethan180countriesandregions,connectingtensofthousandsofnetworks,end-userhasreachedthenumberofstemmillion.Andthemonthlygrowthrateof15%.Becauseofdistance,informationdecaymoreserious,sothisisgenerallytobeleased-linenetwork,throughtheIMP(InterfaceInformationProcessing)protocolandlinelinkuptoformnetworkstructuretosolvetheproblemthroughthepath.Fromthecomputernetworktermsofthefunctionsofitscomponentparts,thepartstocompletetwokindsofmajorfunctions,namely,networkcommunicationsandresourcesharing.Thecomputernetworktoachievenetworkcommunicationdeviceanditssoftware,acollectionknownasthenetworkcommunicationsub-net,thenetworktoachieveresourcesharingofequipmentandsoftwareresourcesofacollectionknownasthesubnet.Inthewideareanetwork,thecommunicationnetworkbyanumberofdedicatedcommunicationprocessor(Internetexplore,thenodeswitches)andrunthesoftware,concentratorsandotherequipmentandconnectthesenodesformthecommunicationlink.Resourcesubnetsfromaccessingallofthecompositionsofthehostanditsexternaldevices.1.2ThecompositionandcharacteristicsofWANWideareanetworkisgeographicallyfarapartmultiplecomputersystems,throughthecommunicationlinesinaccordancewithnetworkprotocolstoconnecttoachievebetweencomputerscommunicatewitheachotheracollectionofcomputersystems.WANfromtheswitches,routers,gateways,modemsandotherdataexchangeequipment,dataconnectivitydevicespose.Ithasastrongtechnicalcomplexity,managementcomplexity,type,variety,connectiondiversity,structuraldiversification,diversificationoftheagreement,applicationcharacteristicsofdiverse.Wideareanetworkisgenerallydividedintothreetypes:circuit-switchednetworks,packetswitchingnetworkandprivatelinenetworks.Agroupofswitchesconnectedtoeachotherconstituteawideareanetwork.Aswitchtypicallyhasmultipleinput/outputinterface,makingittheformationofmanydifferenttopologiestoconnectmultiplecomputers.1.3WAN-relatedtechnicalissuesWiththeWANintroducesthetechnicalissuesrelatedtothefollowingthree.(1)Routing:Sincethesourceanddestinationstationsarenotdirectlyconnected,sothenetworkmustberoutedpacketstransmittedfromonenodetoanothernode,thefinaladoptionoftheentirenetwork.(2)packetswitching:ThebasiccomponentofaWANisapacketswitchbecauseitmovespacketsfromoneconnectiontoanother;itconsistsofspecial-purposehardwarewithaprocessor,memory,andI/Oconnectors.ApacketswitchisillustratedinFigure1.Figure1PacketswitchRoutingtodeterminetheoutputportandthenextonenode,youmustusepacketswitchingtechnologytotransmitfromtheinputporttotheoutputporttoachievetransferbitsthroughthenetworknodes.WANpacketswitchingtechnologyusesasharedcarrierinfrastructure,itisnottheexchangeofprivatelinenetworkconfiguration,andoneononecommunicationpairs.Thiswillenablecarrierstomoreeffectivelyuseofitsinfrastructure,wh