SIST EN 301 141-1 V2.1.1:2005

Integrated Services Digital Network (ISDN); Narrowband Multi-service Delivery System (NMDS); Part 1: NMDS interface specification

To clearify following items: 1)  B-channel selection, 2) usage of STATUS/ENQUIRY message, 3) call collision.

Digitalno omrežje z integriranimi storitvami (ISDN) – Ozkopasovni večstoritveni dostavni sistem (NMDS) – 1. del: Specifikacija vmesnika NMDS

General Information

• Status: Published
• Publication Date: 31-Dec-2004
• ICS: 33.080 - Integrated Services Digital Network (ISDN)
• Technical Committee: SPN - Services and Protocols for Networks
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jan-2005
• Due Date: 01-Jan-2005
• Completion Date: 01-Jan-2005
• Ref Project: ETSI EN 301 141-1 V2.1.1 (2000-11) - Integrated Services Digital Network (ISDN); Narrowband Multi-service Delivery System (NMDS); Part 1: NMDS interface specification

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Integrated Services Digital Network (ISDN); Narrowband Multi-service Delivery System (NMDS); Part 1: NMDS interface specification33.080Digitalno omrežje z integriranimi storitvami (ISDN)Integrated Services Digital Network (ISDN)ICS:Ta slovenski standard je istoveten z:EN 301 141-1 Version 2.1.1SIST EN 301 141-1 V2.1.1:2005en01-januar-2005SIST EN 301 141-1 V2.1.1:2005SLOVENSKI
STANDARD



SIST EN 301 141-1 V2.1.1:2005



ETSIEN301141-1V2.1.1(2000-11)EuropeanStandard(Telecommunicationsseries)IntegratedServicesDigitalNetwork(ISDN);NarrowbandMulti-serviceDeliverySystem(NMDS);Part1:NMDSinterfacespecificationSIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)2ReferenceREN/SPAN-09103-1Keywordsaccess,basic,ISDN,NMDS,PSTNETSI650RoutedesLuciolesF-06921SophiaAntipolisCedex-FRANCETel.:[phone]Fax:[phone]SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/88ImportantnoticeIndividualcopiesofthepresentdocumentcanbedownloadedfrom:http://www.etsi.orgThepresentdocumentmaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshallbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.Usersofthepresentdocumentshouldbeawarethatthedocumentmaybesubjecttorevisionorchangeofstatus.InformationonthecurrentstatusofthisandotherETSIdocumentsisavailableathttp://www.etsi.org/tb/status/Ifyoufinderrorsinthepresentdocument,sendyourcommentto:[e-mail]opartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2000.Allrightsreserved.SIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)3ContentsIntellectualPropertyRights.5Foreword.5Introduction.51Scope.62References.63Definitionsandabbreviations.73.1Definitions.73.2Abbreviations.74Generaldescription.85Layer1functions.85.1PoweringAspects.95.1.1Poweravailablefromthetransmissionsystem.95.1.2NMDSbehaviourunderpowerfailconditions.96Layer2functions.106.1Overview.106.2PSTN-GWlayer2statemachinemodifications.116.3PSTNlayer2activation.117Layer3functionsandmessagedefinitions.127.1General.127.2Errorhandling.127.3Maintenancefunctions.127.3.1ThenewSTATUSENQUIRYandSTATUSmessages.137.3.1.1PSTNmaintenancemessages.137.3.1.1.1TheMAINTENANCESTATUSENQUIRYmessageforPSTNmaintenance.137.3.1.1.2TheMAINTENANCESTATUSmessageforPSTNmaintenance.137.3.1.2ISDNmaintenancemessages.147.3.1.2.1TheMAINTENANCESTATUSENQUIRYmessageforISDNmaintenance.157.3.1.2.2TheMAINTENANCESTATUSmessageforISDNmaintenance.157.3.2Maintenancestatusprocedure.167.3.2.1Normaloperation.167.3.2.2Exceptionalprocedures.167.3.2.2.1NTN.177.3.2.2.2LE.177.3.2.3TimerTmdefinition.178B-channelselectionprocedure.188.1Introduction.188.2B-channelselection.188.2.1LEFunctionality.188.2.1.1GeneralRequirements.188.2.1.1.1HandlingofvalidL3addrvalues.188.2.1.1.2HandlingofinvalidL3addrvalues.198.2.1.2SpecificRequirementsforPSTNCalls.198.2.2NTNFunctionality.198.2.2.1Generalrequirements.198.2.2.2SpecificRequirementsforPSTNCalls.20SIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)4AnnexA(informative):B-channelselection.21A.1General.21A.2Outgoingcalls(NTNtoLE).21A.3Callclearing.22A.4Incomingcalls(LEtoNTN).22A.5PSTN-GWparkedstate.23A.6Clearingfromparkedstate.24A.7Outgoingcalls(NTNtoLE)withdelayedB-channelselection.25AnnexB(informative):BackgroundandmotivationforNMDS.26B.1Transparentsupplementaryserviceoperation.26B.2Operationalbenefits.26AnnexC(informative):ThePSTNprotocoladoptedfortheNMDS.27C.1TheV5PSTNprotocol.27AnnexD(informative):TherelationshipbetweenadirectlyconnectedNMDSandonesupportedviaanaccessnetwork.28D.1Introduction.28AnnexE(informative):Thereasonsforthenewinformationelementvalueschosen.32E.1General.32E.2SpecificcodingrulesforinformationelementsintheV5specifications.32E.3SpecificcodesusedfortheSTATUSENQUIRYinformationelementsforNMDS.32E.4SpecificcodesusedfortheSTATUSinformationelementsforNMDS.32AnnexF(informative):Permanentactivationofbasicaccessdigitalsection.33AnnexG(informative):Remoteequipment-functionalrequirements.34AnnexH(informative):SupplementaryservicesuseableattheNMDS.37H.1ApplicabilityofPSTNsupplementaryservices.37H.2ApplicabilityofISDNsupplementaryservices.37Bibliography.38History.39SIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)5IntellectualPropertyRightsIPRsessentialorpotentiallyessentialtothepresentdocumentmayhavebeendeclaredtoETSI.TheinformationpertainingtotheseessentialIPRs,ifany,ispubliclyavailableforETSImembersandnon-members,andcanbefoundinETSISR000314:"IntellectualPropertyRights(IPRs);Essential,orpotentiallyEssential,IPRsnotifiedtoETSIinrespectofETSIstandards",whichisavailablefromtheETSISecretariat.LatestupdatesareavailableontheETSIWebserver(http://www.etsi.org/ipr).PursuanttotheETSIIPRPolicy,noinvestigation,includingIPRsearches,hasbeencarriedoutbyETSI.NoguaranteecanbegivenastotheexistenceofotherIPRsnotreferencedinETSISR000314(ortheupdatesontheETSIWebserver)whichare,ormaybe,ormaybecome,essentialtothepresentdocument.ForewordThisEuropeanStandard(Telecommunicationsseries)hasbeenproducedbyETSITechnicalCommitteeServicesandProtocolsforAdvancedNetworks(SPAN).Thepresentdocumentispart1ofamulti-partdeliverablecoveringtheIntegratedServicesDigitalNetwork(ISDN);NarrowbandMulti-serviceDeliverySystem(NMDS),asidentifiedbelow:Part1:"NMDSinterfacespecification";Part2:"ProtocolImplementationConformanceStatement(PICS)proformaspecification";Part3:"TestSuiteStructureandTestPurposes(TSS&TP)specificationfortheuser";Part4:"AbstractTestSuite(ATS)andpartialProtocolImplementationeXtraInformationforTesting(PIXIT)proformaspecificationfortheuser".NationaltranspositiondatesDateofadoptionofthisEN:27October2000DateoflatestannouncementofthisEN(doa):31January2001DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):31July2001DateofwithdrawalofanyconflictingNationalStandard(dow):31July2001IntroductionThepresentdocumentspecifiestheprovisionofPublicSwitchedTelephoneNetwork(PSTN)servicesoveranexistingIntegratedServicesDigitalNetwork-BasicAccess(ISDN-BA)digitalsubscriberline(DSL).TodayPSTNterminals-normaltelephones-canbeconnectedtotheS/T-interfaceviaaTerminalAdapter(TA)withthesupportofservicesthatcanbemappedatafeasiblecostfromISDN(principallythebasiccallservices).SIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)61ScopeThepresentstandarddefinesrequirementstosupporttheNarrowbandMulti-serviceDeliverySystem(NMDS)whichprovidesinterfacesconnectedviaaNetworkTerminationNode(NTN)toaLocalExchange(LE),inordertosupportexistingPSTNandISDNservicesoveranexistingISDN-BasicAccessdigitalsubscriberline(DSL).TheNarrowbandMulti-ServiceDeliverySystem(NMDS)mayalsobeconnectedviaaV5interfaceAccessNetwork(AN)toaLocalExchange(LE)inordertoprovideexistingPSTNandISDNservices.ThisoptionalarrangementisdescribedinannexDwhichidentifiestwoalternativemethodstoprovidethesameoverallfunctionality.Thepresentdocumentalsocontainsrequirementswhichrelatetothefunctionalityofa(new)NetworkTerminationNode(NTN)forsupportingbothPublicSwitchedTelephoneNetwork(PSTN)accessandIntegratedServicesDigitalNetwork-BasicAccess(ISDN-BA)S/Treferencepointinterfacesoverasingle(digitalsection)transmissionsystemasusedforexistingISDN-BA.TheNTNencompassesNT2-like(notedNT2*)functionality,physicalPSTNuserport(s)andPSTNprotocolfunctionality.AnNMDSimplementationmaycontainoneISDN-BAportand/oralimitednumberofPSTNports.TypicallyoneortwoPSTNportswouldbesupported.InordertomaintainanevolutionarypathforPSTNservices,thenationalV5PSTNprotocolmappingisassumedtoexistandformsanintegralpartofthisspecification.NOTE:Itisanunderlyingprincipleofthepresentdocumentthat,whereverpracticable,stepsmaybetakentominimizethecostoftheNTN,subjecttomaintainingtherequiredfunctionality.2ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.• Anon-specificreferencetoanETSshallalsobetakentorefertolaterversionspublishedasanENwiththesamenumber.[1]ETSIETR080(1996):"TransmissionandMultiplexing(TM);IntegratedServicesDigitalNetwork(ISDN)basicrateaccess;Digitaltransmissionsystemonmetalliclocallines".[2]ETSIETS300012-1(1996):"IntegratedServicesDigitalNetwork(ISDN);BasicUser-NetworkInterface(UNI);Part1:Layer1specification".[3]ETSIETS300324-1(1994):"VinterfacesatthedigitalLocalExchange(LE);V5.1interfaceforthesupportofAccessNetwork(AN);Part1:V5.1interfacespecification".[4]ETSIETS300347-1(1994):"VinterfacesatthedigitalLocalExchange(LE);V5.2interfaceforthesupportofAccessNetwork(AN);Part1:V5.2interfacespecification".[5]ETSIETS300402-2:"IntegratedServicesDigitalNetwork(ISDN);DigitalSubscriberSignallingSystemNo.one(DSS1)protocol;Datalinklayer;Part2:Generalprotocolspecification[ITU-TRecommendationQ.921(1993),modified]".[6]ITU-TRecommendationI.412(1988):"ISDNuser-networkinterfaces-Interfacestructuresandaccesscapabilities".SIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)7[7]ETSIEN301141-2(V1.2):"IntegratedServicesDigitalNetwork(ISDN);NarrowbandMulti-serviceDeliverySystem(NMDS);Part2:ProtocolImplementationConformanceStatement(PICS)proformaspecification".[8]ITU-TRecommendationM.3603(1992):"ApplicationofmaintenanceprinciplestoISDNbasicrateaccess".[9]ITU-TRecommendationM.3602(1992):"ApplicationofmaintenanceprinciplestoISDNsubscriberinstallations".[10]ETSIETS300297(1995):"IntegratedServicesDigitalNetwork(ISDN);AccessdigitalsectionforISDNbasicaccess".3Definitionsandabbreviations3.1DefinitionsForthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply:NarrowbandMulti-serviceDeliverySystem:systemthatprovidesaninterfacetothenetworkdirectlytotheLEorviaanANtosupportexistingPSTNandISDNservicesoveranISDN-BADSL.NetworkTerminationNode:functionalgroupontheusersideofthedigitalsection(NMDSinterfacenotedT*referencepoint)thatincludesfunctionalitytosupportanISDN-BAportand/oroneormorePSTNports.NetworkTerminationType2*:functionalgroupwithintheNTNwhich,attheusersideoftheT*referencepoint,performsthePSTNlayer2andtheISDNlayer2multiplexinganddemultiplexingovertheDchannel,andonlyinterprets(andthenrelays)thelayer3messagestoswitchtheBchannelstotheISDNaccessandthePSTNGatewaysasinstructedbythesignallingmessages.PSTN-Gateway:functionalgroupwithintheNTNwhichterminatesthePSTNinterfaceattheNTN.T*referencepoint:referencepointwhichprovidesaccesstotheNMDS,betweenthenetworkterminationofthedigitalsection(NT1)andtheNetworkTerminationNodefunctionalgroup.V1*referencepoint:V1referencepointwiththeadditionofPSTNfunctionalityrequiredtosupporttheNMDS.3.2AbbreviationsForthepurposesofthepresentdocument,thefollowingabbreviationsapply:ANAccessNetworkBCCBearerChannelControlCPECustomerPremisesEquipmentDLCIDataLinkConnectionIdentifierDSLDigitalSubscriberLineDTMFDualToneMulti-FrequencyISDNIntegratedServicesDigitalNetworkISDN-BAIntegratedServicesDigitalNetwork-BasicAccessLELocalExchangeNMDSNarrowbandMulti-serviceDeliverySystemNTNetworkTerminationNT1NTtype1(seeETR080[1])NT2*NetworkTerminationType2*(seethedefinitioninsubclause3.1above)NTNNetworkTerminationNodeNWKNetworkLayerPSTNPublicSwitchedTelephoneNetworkPSTN-GWPSTNGatewaySAPIServiceAccessPointIdentifierTATerminalAdapterSIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)8TETerminalEquipmentTEITerminalEndpointIdentifierUNIUserNetworkInterface4GeneraldescriptionThepurposeoftheNMDSistosupportbothISDN-BAandoneormorePSTNuserportsinthesamemannersuchthattheyappeartotheuserasiftheyweredirectlyconnectedtotheLE.ThesupportofISDN-BAuserportsutilizesthesametypeoffunctionsasusedbyanNT1definedinETR080[1],whilstPSTNuserportsaresupportedusingthesamePSTNprotocolasdefinedintheV5.1interfacestandardETS300324-1[3]withsomemodifications.TheLEisserviceresponsibleforandcontrolsthetones(voicemessagesetc.)sentandreceivedovertheNMDS.Seefigure1forthefunctionalarchitectureofNMDS.PSTNUserPortUNIISDN-BADSLNTNCallControlLEISDNUserPortnationalPSTNprotocolISDNlayer2mngmntFigure1:GeneralNMDSfunctionaldiagramTheNarrowbandMulti-serviceDeliverySystem(NMDS)isdefinedattheT*referencepointandthecomplementaryV1*referencepointasshowninfigure2.OnanyNMDS,theLEmaysupportupto10PSTN(analogue)linesandtheNTNmayprovideupto10PSTN(analogue)accessports.TheprovisionofPSTNandISDNaccessportsintheLErequiresabilateralagreementbetweentheuserandtheserviceprovideratsubscriptiontime.5Layer1functions• StructureThegeneralaccessstructureisdescribedinITU-TRecommendationI.412[6].TheaccessstructureforISDN-BAinITU-TRecommendationI.412[6]isvalidalsoforthePSTNapplication.Thelayer1transportingthefullNMDSfunctionalityfromtheNTNtotheLEshallbeanISDN-BAlayer1.• ISDN-BADigitalSectionInordertopermittransparentoperationviaanAN,thereshallbenochangestotheISDN-BAdigitalsectionlayer1protocols.• ISDN-BAUNILayer1attheISDN-BAUNIshallbeinaccordancewithETS300012-1[2].• ActivationProcedures-NTNTheNTNshallpermitlayer1activationfromtheISDNUNIandlayer1activation/deactivationfromthenetwork.InordertokeeptheNTNsimple,thePSTNgatewayshallnotrequire"userside"activationprocedures.SIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)9TheNTNshallalsoallowthedigitalsectiontobeactivatedregardlessoftheelectricalconditionsprevailingattheISDNUNIandPSTNport.Oncethelayer1isactivatedtheNTNshallalwaystransmittheACTbitsetto1towardsthenetwork.ThisistopreventthepossibilityoftheLE/ANdeactivatingthedigitalsectionaspartoftherecoveryactionsresultingfromanISDNUNIerror.(DetailsoftheACTbitcanbefoundinETR080[1]annexAfigureA.3andsubclauseA.8.3.2.2.Itspurposeistoindicatereadinessforlayer2.)• LE/ANThenetworkshallmaintainthedigitalsectioninapermanentlyactivatedstatewheneverthePSTNprotocolsaretobesupported.Thepermanentactivationofthedigitalsectionmayinterferewithcertainmaintenanceoperationsnormallyprovidedovertheembeddedoperationschannel.TheLEshallbeabletodetecttheactivationstateoftheISDNUNIwhichwouldhaveprevailedifthePSTNportshadnotbeenpresent,usingamessage-basedmaintenancemechanismatlayer3(seesubclause7.3.1.2).• DiagnosticsTheNTNshallsupportfullISDNlayer1diagnosticloopcapability.NT2*LTPSTN-GWZNTNETV*ISDNbasicaccessdigitalsection1LEorANETS300297[10]Rec.M.3603[8]S/TAccessconnectionelementRec.M.3602[9]Customerequipment2B+D(2B1Q/4B3T)ISDNbasicaccesstransmissionsystemNT1T*ETS300012-1[2]NOTE:Thefunctionalityandlayoutshowninfigure2canonlybeoneparticularexampleandisnotrepresentativeofallarchitectureswhereNMDScanbeapplied.InactualimplementationstheNT1functionalgroupislikelytobephysicallyintegratedinanequipmentrealizingtheNTNfunctionality.Figure2:AnexampleofanNMDSscenarioforNMDS5.1PoweringAspects5.1.1PoweravailablefromthetransmissionsystemThepoweravailableforNMDSsupportistheactualpowerbudgetprovidedbytheexistingISDN-BAdigitalsection.AdditionalpowerisexpectedtobeprovidedlocallytotheNTN.WhatmayhappenunderlocalpowerfailconditionswithrespecttoNTNuserportsisdescribedbelow.HencetherearenodeviationsfromtherequirementsspecifiedintheISDN-BAstandardsinordertosupportNMDS.5.1.2NMDSbehaviourunderpowerfailconditionsTheISDN-BAUNIstandard(ETS300012-1[2])describesapotentialrequirementthatadesignatedinstrumentmaybemadeavailableonanS/TInterface.Ifthisdesignatedinstrumentisavailable,thenitshallbecapableof(atleast)makingemergencytelephonecalls.SIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)10ForthePSTN,thesituationisnotmandatedonaEuropeanwidebasisanddependsuponnationallyagreedregulationswhichareoutsidethescopeofthepresentdocument.TheNMDSmaybecomprisedofoneormorePSTNports,potentiallyaswellasanISDN-BAport.Henceitisnotpossibletodefineinastandardmandatorybehaviourunderpower-failconditions.Whatismorerelevantisthatmanufacturersareabletoadequatelydefinetheirsystem'sbehaviourunderpowerfailureconditions.Forthisreason,aclausehasbeeninsertedintotheProtocolImplementationConformanceStatement(PICS)document,EN301141-2[7],wheresuchbehaviourmaybeexplained.6Layer2functions6.1OverviewThelayer2usedwithintheNMDSsystem,usedforbothPSTNandISDN-BAservices,shallbeinaccordancewithETS300402-2[5]butwiththefollowingrestrictions.TheLElayer2statemachineshallbeasperETS300402-2[5].ThePSTNgatewaylayer2statemachineshallbeasdefinedinsubclause6.2ofthepresentdocument,providingarestrictedfunctionalityversionofthestatemachineinETS300402-2[5].ThePSTNgatewayshalluseasinglepermanentlyactivateddatalinkwithafixedDataLinkConnectionIdentifier(DLCI)forallcommunicationwiththenetwork.TheDLCIshallconsistofaPSTNTerminalEndpointIdentifier(TEI)allocatedfromtheautomaticTEIvalues(i.e.64-126)andServiceAccessPointIdentifier(SAPI)setequalto0.TEIvalues117to126shallbereservedforPSTNusewhenNMDSisimplementedonanaccess.ThefirstPSTNgatewaytobefittedshalluseTEI126andbeidentifiedasLine1.TEIvalues117to125arereservedforfurtherPSTNgateways,lines2to10,asshowninthetable1.Table1:AllocationofTEItoPSTNportsTEIvalueLinenumber12611252124312341225121612071198118911710ThePSTNgatewayshallnotsupportthebroadcastdatalink,orTEImanagementprocedures,andshallnotinitiatelayer2establishment,i.e.theDL_ESTABLISH_REQUESTprimitiveintheTEIassignedstateshallnotbesupported.OntheISDNport,point-to-point(i.e.TEI0)orpoint-to-multipointproceduresmaybesupportedusingthefullISDNTEIassignmentproceduresascurrentlydefined.TheseincludeTEIassignmentandremovalprocedures.However,somepreviouslyavailablevaluesarenowreserved(seetable1).ItisexpectedthatsomeimplementationsmayprovideadditionalPSTN-GWseitherasseparateequipmentconnectedtotheS/TInterfaceorasfurtherintegratedentities.IneachcasetheTEIallocationsshallcomplywiththoseshownintable1.TheTEIassociatedwitheachexternalPSTN-GWshallbepreprovisioned.SIST EN 301 141-1 V2.1.1:2005



ETSIETSIEN301141-1V2.1.1(2000-11)116.2PSTN-GWlayer2statemachinemodificationsThemodificationsrequiredtotheBAlayer2statemachineforthePSTN-GWarespecifiedbelowasalistofdifferencestothestatemachinecontainedinannexDofETS300402-2[5].Deletestates1,2,3,5.0,5.2and6.Deletethefollowinginputevents:-DL-ESTABLISH-REQUEST;-DL-RELEASE-REQUEST;-DL-UNITDATA-REQUEST;-UIFRAMEINQUEUE;-MDL-ASSIGN-REQUEST;-MDL-REMOVE-REQUEST;-MDL-ERROR-RESPONSE;-T203TIME-OUT.Renumberstate4,andallreferencestoit,tostate9;renamethestateto"LINKNOTESTABLISHED".Deleteallinstancesofthefollowingoutputeventsreplacingtheeventwith"-"ifitwastheonlyactionassociatedwiththeinputevent/statecombinationunderconsideration:-DISCUIQUEUE;-STARTT203;-STOPT203;-RESTARTT203;-MDL-ERR-IND(allvariants);-DL-UNIT-DATA-IND.Replaceallinstancesof"DISCIandUIQUEUES"with"DISCIQUEUE".Forinputevent"T200TIME-OUT"instates7.0throughtostate7.3deletethe"either"option.Forinputevent"T200TIME-OUT;RC


ETSIETSIEN301141-1V2.1.1(2000-11)127Layer3functionsandmessagedefinitions7.1GeneralThePSTNnetworklayer(NWK)protocolshallbeinaccordancewithETS300324-1[3]clause13subjecttothefollowingmodificationsandrestrictions.• TheNTNshallbeconsideredasimplementingtheANpartsthroughoutETS300324-1[3]clause13.• ThePSTNcallcontrolproceduresofETS300324-1[3]shallbeused.However,thePSTNPortblockingandthePSTNRestartproceduresdefinedinETS300324-1[3]donotapplytotheNMDS.HencethefollowingeventsdescribedinETS300324-1[3]PSTNfunctionalstatemachines(clause13)arenotapplicable:MDU-CRTL(portblocked),MDU-CTRL(portunblocked),MDU-CTL(restartrequest)MDU-CTRL(restartcomplete).ItresultsthatthestatesAN0,AN6,LE0andLE6definedinETS300324-1[3](subclauses13.2.1.1and13.2.1.2)fortheV5.1interfacearenotusedbytheNMDSstatemachine.• ThemeaninganddefinitionoftheL3addrfield(ETS300324-1[3]subclause13.4.3)ismodifiedtosupporttheB-channelselectionfunctionasdescribedinclause8ofthepresentdocument.• ThepresentdocumentprovidesadditionstothemessageformatsandprocedurestothosefoundinETS300324-1[3].Thesearedocumentedinsubclause7.3.Theydefineanddescribenewmaintenancestatusenquiryprocedures.• Theprotocoldiscriminatorvaluefortheadditionalmessagesdefinedinthepresentdocument(i.e.MAINTENANCESTATUSandMAINTENANCESTATUSENQUIRY)shallbethesameasforETS300324-1[3],i.e.48H.TheNTNshallsupportthenationalPSTNrequirementsforallapplicablesignals(includingcollisions).AlltonesandannouncementsgeneratedbythenetworkshallbepassedasinbandsignallingtransparentlyovertheB-channeltothecustomer.IntheeventofnoB-channelbeingavailablethentheproceedindicationshallnotbegiventothecustomeruntilachannelbecomesavailablei.e.theproceedindicationshallnotbegeneratedbythePSTN-GW.DTMFdialleddigitsshallbepassedtransparentlyovertheB-channeltothenetwork.ThenationalPSTNmappingsarebeyondthescopeofthepresentdocument.7.2ErrorhandlingTheLEshallsupportthefullerrorhandlingproceduresdefinedinETS300324-1[3]clause13,relatingtotheV5.1PSTNprotocolwithadditionalrequirementsasindicatedinthepresentdocument.TheNTNshallsupportthefullerrorhandlingproceduresasdefinedinETS300324-1[3]clause13fortheAN,relatingtotheV5.1PSTNprotocolwithadditionalrequirementsasindicatedinthepresentdocument.Inaddition,incaseofaPSTNlayer2failure,ifaPSTNcallisestablished,thiscallisreleasedbytheLE.Uponsuccessfulre-establishmentofthePSTNlayer2,theLEshallsendaDISCONNECTCOMPLETEmessagetotheNTNandgointothe"Nullstate(LE1)"inordertoensuresynchronizationoftheNTNPSTNGWandtheLEstatemachines.NOTE:Callreleasemaycauseanetworkclearingmessagewithacause#27,destinationoutoforder,or#41,temporaryfailure,andthelocationfieldsetto'publicnetworkservingtheremoteuser',tobesenttowardstheexchangeservingtheremoteuser.7.3MaintenancefunctionsThisclausedefinesthemechanismfortheLEtobeabletodetermineifcustomerequipmentisconnectedtothePSTN-GWandtodeterminethesynchronizationstatusoftheS/Tinterface.Thesupportofthe(ISDNandPSTN)maintenancemechanismsbytheLEandNTNisoptional.ItshallusetheLayer3STATUSandSTATUSENQUIRYmessagesasdefinedinETS300324-1[3]subclause13.4,exceptthattheStateandCauseinformationelementsalreadydefinedfortheSTATUSarechangedtooptionalandonlyoneofthenewvariablelengthinformationelementsdefinedbelowshallbeincludedinaSTA
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