ITU-T J.127 (06 2004) (英) Transmission protocol fo

INTERNATIONALTELECOMMUNICATIONUNIONITU-TJ.127TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITU(06/2004)SERIESJ:CABLENETWORKSANDTRANSMISSIONOFTELEVISION,SOUNDPROGRAMMEANDOTHERMULTIMEDIASIGNALSInteractivesystemsfordigitaltelevisiondistributionTransmissionprotocolformultimediawebcastingoverTCP/IPnetworksITU-TRecommendationJ.127ITU-TRec.J.127(06/2004)iITU-TRecommendationJ.127TransmissionprotocolformultimediawebcastingoverTCP/IPnetworksSummaryThisRecommendationdefinesatransmissionprotocolformultimediawebcastingoverTCP/IPnetworks.Theprotocolconsistsofapresentationdescriptionandsessioncontrol.ThepresentationdescriptionisbasedontheXHTMLformat,anditspecifiespropertiesofthemediasuchasURI,contenttype,contentsize,accountinginformation,andsoon.Firstofall,aterminalreceivesthepresentationdescription,andsetsupinaccordancewiththedescription.Thentheterminalstartstransmissionofthemediainaccordancewiththesessioncontrol,whichisbasedonHTTP.Thesessioncontrolsupportsstartingthesession,retrievingthemediadataandendingthesession.Inaddition,aremotecameracontrolschemeisalsodefinedinthesessioncontrol.SincetheprotocoldefinedinthisRecommendationissimilartothe(2001-2004)undertheITU-TRecommendationA.8procedure.iiITU-TRec.J.127(06/2004)FOREWORDTheInternationalTelecommunicationUnion(ITU)istheUnitedNationsspecializedagencyinthefieldoftelecommunications.TheITUTelecommunicationStandardizationSector(ITU-T)isapermanentorganofITU.ITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.TheWorldTelecommunicationStandardizationAssembly(WTSA),whichmeetseveryfouryears,establishesthetopicsforstudybytheITU-Tstudygroupswhich,inturn,produceRecommendationsonthesetopics.TheapprovalofITU-TRecommendationsiscoveredbytheprocedurelaiddowninWTSAResolution1.InsomeareasofinformationtechnologywhichfallwithinITU-T'spurview,thenecessarystandardsarepreparedonacollaborativebasiswithISOandIEC.NOTEInthisRecommendation,theexpressionAdministrationisusedforconcisenesstoindicatebothatelecommunicationadministrationandarecognizedoperatingagency.CompliancewiththisRecommendationisvoluntary.However,theRecommendationmaycontaincertainmandatoryprovisions(toensuree.g.interoperabilityorapplicability)andcompliancewiththeRecommendationisachievedwhenallofthesemandatoryprovisionsaremet.Thewordsshallorsomeotherobligatorylanguagesuchasmustandthenegativeequivalentsareusedtoexpressrequirements.TheuseofsuchwordsdoesnotsuggestthatcompliancewiththeRecommendationisrequiredofanyparty.INTELLECTUALPROPERTYRIGHTSITUdrawsattentiontothepossibilitythatthepracticeorimplementationofthisRecommendationmayinvolvetheuseofaclaimedIntellectualPropertyRight.ITUtakesnopositionconcerningtheevidence,validityorapplicabilityofclaimedIntellectualPropertyRights,whetherassertedbyITUmembersorothersoutsideoftheRecommendationdevelopmentprocess.AsofthedateofapprovalofthisRecommendation,ITUhadnotreceivednoticeofintellectualproperty,protectedbypatents,whichmayberequiredtoimplementthisRecommendation.However,implementorsarecautionedthatthismaynotrepresentthelatestinformationandarethereforestronglyurgedtoconsulttheTSBpatentdatabase.ITU2004Allrightsreserved.Nopartofthispublicationmaybereproduced,byanymeanswhatsoever,withoutthepriorwrittenpermissionofITU.ITU-TRec.J.127(06/2004)iiiCONTENTSPage1Scope............................................................................................................................12References.....................................................................................................................12.1Normativereferences......................................................................................12.2Informativereferences....................................................................................13Termsanddefinitions...................................................................................................14Abbreviations................................................................................................................25PresentationDescription...............................................................................................25.1XHTMLPresentationDescriptionFormat.....................................................25.2objectElement...........................................................................................35.3paramElement...........................................................................................46Sessioncontrol..............................................................................................................66.1Retrievalofthecontentsize...........................................................................66.2Datatransmission...........................................................