ITU-T X.2(03 2000) International data transmission

INTERNATIONALTELECOMMUNICATIONUNIONITU-TX.2TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITU(03/2000)SERIESX:DATANETWORKSANDOPENSYSTEMCOMMUNICATIONSPublicdatanetworks–ServicesandfacilitiesInternationaldatatransmissionservicesandoptionaluserfacilitiesinpublicdatanetworksandISDNsITU-TRecommendationX.2(PreviouslyCCITTRecommendation)ITU-TX-SERIESRECOMMENDATIONSDATANETWORKSANDOPENSYSTEMCOMMUNICATIONSForfurtherdetails,pleaserefertoITU-TListofRecommendations.PUBLICDATANETWORKSServicesandfacilitiesX.1–X.19InterfacesX.20–X.49Transmission,signallingandswitchingX.50–X.89NetworkaspectsX.90–X.149MaintenanceX.150–X.179AdministrativearrangementsX.180–X.199OPENSYSTEMSINTERCONNECTIONModelandnotationX.200–X.209ServicedefinitionsX.210–X.219Connection-modeprotocolspecificationsX.220–X.229Connectionless-modeprotocolspecificationsX.230–X.239PICSproformasX.240–X.259ProtocolIdentificationX.260–X.269SecurityProtocolsX.270–X.279LayerManagedObjectsX.280–X.289ConformancetestingX.290–X.299INTERWORKINGBETWEENNETWORKSGeneralX.300–X.349SatellitedatatransmissionsystemsX.350–X.399MESSAGEHANDLINGSYSTEMSX.400–X.499DIRECTORYX.500–X.599OSINETWORKINGANDSYSTEMASPECTSNetworkingX.600–X.629EfficiencyX.630–X.639QualityofserviceX.640–X.649Naming,AddressingandRegistrationX.650–X.679AbstractSyntaxNotationOne(ASN.1)X.680–X.699OSIMANAGEMENTSystemsManagementframeworkandarchitectureX.700–X.709ManagementCommunicationServiceandProtocolX.710–X.719StructureofManagementInformationX.720–X.729ManagementfunctionsandODMAfunctionsX.730–X.799SECURITYX.800–X.849OSIAPPLICATIONSCommitment,ConcurrencyandRecoveryX.850–X.859TransactionprocessingX.860–X.879RemoteoperationsX.880–X.899OPENDISTRIBUTEDPROCESSINGX.900–X.999RecommendationX.2(03/2000)iITU-TRECOMMENDATIONX.2INTERNATIONALDATATRANSMISSIONSERVICESANDOPTIONALUSERFACILITIESINPUBLICDATANETWORKSANDISDNsSummaryThisRecommendationdescribesinternationaldatatransmissionservices(leasedcircuit,circuitswitched,packetswitched,andframerelay)andoptionaluserfacilitiesinpublicdatanetworksandISDNs.Thisrevisionincludesoptionaluserfacilitiesforpriorityandserviceclassesaspectsofframerelaydatatransmissionservice.TherevisionalsotakesintoaccounttheaddressingaspectsconnectedwiththeusingofE.164EscapeCode0.SourceITU-TRecommendationX.2wasrevisedbyITU-TStudyGroup7(1997-2000)andwasapprovedundertheWTSCResolutionNo.1procedureon31March2000.iiRecommendationX.2(03/2000)FOREWORDITU(InternationalTelecommunicationUnion)istheUnitedNationsSpecializedAgencyinthefieldoftelecommuni-cations.TheITUTelecommunicationStandardizationSector(ITU-T)isapermanentorganoftheITU.TheITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.TheWorldTelecommunicationStandardizationConference(WTSC),whichmeetseveryfouryears,establishesthetopicsforstudybytheITU-TStudyGroupswhich,intheirturn,produceRecommendationsonthesetopics.TheapprovalofRecommendationsbytheMembersoftheITU-TiscoveredbytheprocedurelaiddowninWTSCResolutionNo.1.InsomeareasofinformationtechnologywhichfallwithinITU-T’spurview,thenecessarystandardsarepreparedonacollaborativebasiswithISOandIEC.NOTEInthisRecommendation,theexpressionAdministrationisusedforconcisenesstoindicatebothatelecommunicationadministrationandarecognizedoperatingagency.INTELLECTUALPROPERTYRIGHTSTheITUdrawsattentiontothepossibilitythatthepracticeorimplementationofthisRecommendationmayinvolvetheuseofaclaimedIntellectualPropertyRight.TheITUtakesnopositionconcerningtheevidence,validityorapplicabilityofclaimedIntellectualPropertyRights,whetherassertedbyITUmembersorothersoutsideoftheRecommendationdevelopmentprocess.AsofthedateofapprovalofthisRecommendation,theITUhadnotreceivednoticeofintellectualproperty,protectedbypatents,whichmayberequiredtoimplementthisRecommendation.However,implementorsarecautionedthatthismaynotrepresentthelatestinformationandarethereforestronglyurgedtoconsulttheTSBpatentdatabase.
ITU2000Allrightsreserved.Nopartofthispublicationmaybereproducedorutilizedinanyformorbyanymeans,electronicormechanical,includingphotocopyingandmicrofilm,withoutpermissioninwritingfromtheITU.RecommendationX.2(03/2000)iiiCONTENTSPage1Introduction..............................................................................................................................................22Circuitwitcheddatatransmissionservice..................................................................................................23Packetswitcheddatatransmissionservices................................................................................................23.1Directaccesstoapacketswitcheddatatransmissionservice.........................................................23.2Portaccesstoapacketswitcheddatatransmissionservice(userclassesofservice20-26and29)..63.3Portaccesstoapacketswitcheddatatransmissionservice(userclassesofservice8-12,26and30)........................................................................................................................................8