无线通信 外文原文

胡琼：外文原文1WirelessTransactionProtocolFrom：KingTuEnglishlearningsourcebase3.TerminologyandConventions3.1.ConventionsThekeywords“MUST”,“MUSTNOT”,“REQUIRED”,“SHALL”,“SHALLNOT”,“SHOULD”,“SHOULDNOT”,“RECOMMENDED”,“MAY”,and“OPTIONAL”inthisdocumentaretobeinterpretedasdescribedin[RFC2119].Allsectionsandappendixes,except“Scope”,arenormative,unlesstheyareexplicitlyindicatedtobeinformative.3.2.DefinitionsDeviceAddressTheuniquenetworkaddressassignedtoadeviceandfollowingtheformatdefinedbyaninternationalstandardsuchasE.164forMSISDNaddresses,X.121forX.25addressesorRFC791forIPv4addresses.Anaddressuniquelyidentifiesthesendingand/orreceivingdevice.InitiatorTheWTPproviderinitiatingatransactionisreferredtoastheInitiator.MobileDeviceReferstoadevice,suchasaphone,pager,orPDA,connectedtothewirelessnetworkviaawirelelesslink.Whiletheterm‘mobile’impliesthedeviceisfrequentlymoving,itMAYalsoincludefixedorstationarywirelessdevices(i.e.wirelessmodemsonelectricmeters)connectedtoawirelessnetwork.NetworkTypeNetworktypereferstoanynetwork,whichisclassifiedbyacommonsetofcharacteristics(i.e.airinterface)andstandards.ExamplesofnetworktypesincludeGSM,CDMA,IS-136,iDEN,,FLEX,ReFLEX,andMobitex.Eachnetworktypemaycontainmultipleunderlyingbearerservices.ProtocolControlInformation(PCI)InformationexchangedbetweenWTPentitiestocoordinatetheirjointoperation.ProtocolDataUnit(PDU)AunitofdataspecifiedintheWTPprotocolandconsistingofWTPprotocolcontrolinformationandpossiblyuserdata.ResponderTheWTPproviderrespondingtoatransactionisreferredtoastheResponder.ServiceDataUnit(SDU)Unitofinformationfromanupperlevelprotocolthatdefinesaservicerequesttoalowerlayerprotocol.ServicePrimitiveAnabstract,implementationindependentinteractionbetweenaWTPuserandtheWTPprovider.TransactionThetransactionistheunitofinteractionbetweentheInitiatorandtheResponder.胡琼：外文原文2AtransactionbeginswithaninvokemessagegeneratedbytheInitiator.TheResponderbecomesinvolvedwithatransactionbyreceivingtheinvoke.InWTPseveraltransactionclasseshavebeendefined.Theinvokemessageidentifiesthetypeoftransactionrequestedwhichdefinestheactionrequiredtocompletethetransaction.UserDataThedatatransferredbetweentwoWTPentitiesonbehalfoftheupperlayerentities(e.g.sessionlayer)forwhomtheWTPentitiesareprovidingservices.WTPProviderAnabstractmachinewhichmodelsthebehaviourofthetotalityoftheentitiesprovidingtheWTPservice,asviewedbytheuser.WTPUserAnabstractrepresentationofthetotalityofthoseentitiesinasinglesystemthatmakeuseoftheWTPservice.ExamplesofWTPusersincludetheWAPsessionprotocolWSPoranapplicationthatrunsdirectlyontoWTP.3.3.AbbreviationsAPIApplicationProgrammingInterfaceCDMACodeDivisionMultipleAccessCDPDCellularDigitalPacketDataESARExtendedSegmentationAndReassemblyETSIEuropeanTelecommunicationStandardizationInstituteGPRSGeneralPacketRadioServiceGSMCGlobalSystemforMobileCommunicationGTRGroupTrailer,indicatestheendofpacketgroupGUTSGeneralUDPTransportServiceIDENIntegratedDigitalEnhancedNetworkIPInternetProtocolLSBLeastsignificantbitsMDFCMoreDataFlagClearedMPLMaximumPacketLifetimeMSMobileStationMSBMostsignificantbitsMSISDNMobileSubscriberISDN(Telephonenumberoraddressofdevice)PCIProtocolControlInformationPDUProtocolDataUnitPSNPacketSequenceNumberRTTRound-TripTimeSARSegmentationandRe-assemblySAPServiceAccessPointSDUServiceDataUnitSMSShortMessageServiceSPTServerProcessingTimeTIA/EIATelecommunicationsIndustryAssociation/ElectronicIndustryAssociationTPITransportInformationItemTTRTransmissionTrailer胡琼：外文原文3UDPUserDatagramProtocolUSSDUnstructuredSupplementaryServiceDataWAPWirelessApplicationProtocolWDPWirelessDatagramProtocolWSPWirelessSessionProtocolWTPWirelessTransactionProtocol4.ProtocolOverview4.1.ProtocolFeaturesThefollowinglistsummarizesthefeaturesofWTP.Threeclassesoftransactionservice:Class0:UnreliableinvokemessagewithnoresultmessageClass1:ReliableinvokemessagewithnoresultmessageClass2:Reliableinvokemessagewithexactlyonereliableresultmessage(1)Reliabilityisachievedthroughtheuseofuniquetransactionidentifiers,acknowledgements,duplicateremovalandre-transmissions.(2)Noexplicitconnectionsetuporteardownphases.Explicitconnectionopenand/orcloseimposesexcessiveoverheadonthecommunicationlink.(3)Optionallyuser-to-userreliability:theWTPuserconfirmseveryreceivedmessage.(4)Optionally,thelastacknowledgementofthetransactionMAYcontainoutofbandinformationrelatedtothetransaction.Forexample,performancemeasurements.(5)ConcatenationMAYbeused,whereapplicable,toconveymultipleProtocolDataUnitsinoneServiceDataUnitofthedatagramtransport.(6)Messageorientation.Thebasicunitofinterchangeisanentiremessageandnotastreamofbytes.(7)Theprotocolprovidesmechanismstominimisethenumberoftransactionsbeingreplayedastheresultofduplicatepackets.(8)Abortofoutstandingtransaction,includingflushingofunsentdatabothinclientandserver.Theabortcanbetriggeredbytheusercancelingarequestedservice.(9)Forreliableinvokemessages,bothsuccessandfailureisreported.IfaninvokecannotbehandledbytheResponder,anabortmessagewillbereturnedtotheInitiatorinsteadoftheresult.（10）Theprotocolallowsforasynchronoust