ETSI EN 300 201 V1.2.1 (2001-05)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digitalno omrežje z integriranimi storitvami (ISDN) - Dopolnilna storitev: predaja klica, ko ni odziva (CFNR) - Opis storitveIntegrated Services Digital Network (ISDN); Call Forwarding No Reply (CFNR) supplementary service; Service description33.080Digitalno omrežje z integriranimi storitvami (ISDN)Integrated Services Digital Network (ISDN)ICS:Ta slovenski standard je istoveten z:EN 300 201 Version 1.2.1SIST EN 300 201 V1.2.1:2004en01-april-2004SIST EN 300 201 V1.2.1:2004SLOVENSKI
STANDARD



SIST EN 300 201 V1.2.1:2004



ETSIEN300201V1.2.1(2001-05)EuropeanStandard(Telecommunicationsseries)IntegratedServicesDigitalNetwork(ISDN);CallForwardingNoReply(CFNR)supplementaryservice;ServicedescriptionSIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)2ReferenceREN/SPAN-110091KeywordsCF,ISDN,stage1,supplementaryserviceETSI650RoutedesLuciolesF-06921SophiaAntipolisCedex-FRANCETel.:+33492944200Fax:+33493654716SiretN°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:editor@etsi.frCopyrightNotificationNopartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2001.Allrightsreserved.SIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)3ContentsIntellectualPropertyRights.5Foreword.51Scope.62References.63Definitionsandabbreviations.73.1Definitions.73.2Abbreviations.74Description.85Procedures.85.1Provisionandwithdrawal.85.2Normalprocedures.95.2.1Registrationanderasure.95.2.2Activationanddeactivation.95.2.2.1Activation.95.2.2.2Deactivation.105.2.3Invocationandoperation.105.2.3.1Serveduser'sview.115.2.3.2Forwarded-touser'sview.115.2.3.3Callinguser'sview.115.2.4Interrogation.135.3Exceptionalprocedures.135.3.1Registrationanderasure.135.3.2Activationanddeactivation.145.3.2.1Activation.145.3.2.2Deactivation.155.3.3Invocationandoperation.155.3.4Interrogation.166Interworkingrequirements.166.1Interworkingwithnon-ISDNs.166.2Interworkingwithprivatenetworks.177InteractionwithISDNsupplementaryservices.177.1Adviceofcharge.177.1.1Adviceofchargeatcallset-up.177.1.2Adviceofchargeduringthecall.177.1.3Adviceofchargeattheendofthecall.177.2Callwaiting.187.3Callhold.187.4Explicitcalltransfer.187.5Numberidentificationservices.187.5.1Callinglineidentificationpresentation.187.5.2Callinglineidentificationrestriction.187.5.3Connectedlineidentificationpresentation.187.5.4Connectedlineidentificationrestriction.197.6Closedusergroup.197.7Callcompletionservices.197.7.1Completionofcallstobusysubscriber.197.7.2Completionofcallsonnoreply.207.8Conferenceservices.207.8.1Conferencecall,add-on.207.8.2Meetme-conference.207.9Directdiallingin.207.10Diversionservices.20SIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)47.10.1Callforwardingunconditional.207.10.2Callforwardingbusy.207.10.3Callforwardingnoreply.217.10.4Calldeflection.217.10.5Selectivecallforwarding.217.11Freephone.217.12Maliciouscallidentification.217.13Multiplesubscribernumber.217.14Sub-addressing.227.15Terminalportability.227.16Threeparty.227.17User-to-usersignalling.227.18Callbarringservices.237.18.1Outgoingcallbarring-fixed.237.18.2Outgoingcallbarring-usercontrolled.237.19Messagewaitingindication.23AnnexA(informative):Interactionbetweenuser-to-usersignallingandtheCFNRsupplementaryservice.24History.25SIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)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).AsaneditorialcommentreceivedduringOAPtitlehasbeenalignedwiththeformerversionsofthisstandard.NationaltranspositiondatesDateofadoptionofthisEN:25May2001DateoflatestannouncementofthisEN(doa):31August2001DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):28February2002DateofwithdrawalofanyconflictingNationalStandard(dow):28February2002SIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)61ScopeThepresentdocumentdefinesthestageoneoftheCallForwardingNoReply(CFNR)supplementaryserviceforthepan-EuropeanIntegratedServicesDigitalNetwork(ISDN)asprovidedbyEuropeantelecommunicationoperators.Stageoneisanoverallservicedescriptionfromtheuser'spointofview(seeITU-TRecommendationI.130[1]),butdoesnotdealwiththedetailsofthehumaninterfaceitself.ThepresentdocumentdefinestheinterworkingrequirementsofprivateISDNswiththepublicISDN.Inaddition,thepresentdocumentspecifiesthebasefunctionalitywheretheserviceisprovidedtotheuserviaaprivateISDN.ThepresentdocumentdoesnotspecifytheadditionalrequirementswheretheserviceisprovidedtotheuserviatelecommunicationsnetworkthatisnotanISDNbutdoesincludeinterworkingrequirementsofothernetworkswiththepublicISDN.Interactionswithsupplementaryservicesnotlistedinclause7areoutsidethescopeofthepresentdocument.Chargingprinciplesareoutsidethescopeofthepresentdocument.TheCFNRsupplementaryserviceenablesaservedusertohavethenetworkredirecttoanotherusercallswhichareaddressedtotheserveduser'sISDNnumber,andforwhichtheconnectionisnotestablishedwithinadefinedperiodoftime.TheCFNRsupplementaryservicemayoperateonallcalls,orjustthoseassociatedwithspecifiedbasicservices.Theserveduser'sabilitytooriginatecallsisunaffectedbytheCFNRsupplementaryservice.TheCFNRsupplementaryserviceisapplicabletoallcircuit-switchedtelecommunicationservices.ThepresentdocumentisapplicabletothestagetwoandstagethreestandardsfortheISDNCFNRsupplementaryservice.Theterms"stagetwo"and"stagethree"arealsodefinedinITU-TRecommendationI.130[1].Wherethetextindicatesthestatusofarequirement(i.e.asstrictcommandorprohibition,asauthorizationleavingfreedom,orasacapabilityorpossibility),thisshallbereflectedinthetextoftherelevantstagetwoandstagethreestandards.Furthermore,conformancetothepresentdocumentismetbyconformingtothestagethreestandardswiththefieldofapplicationappropriatetotheequipmentbeingimplemented.Therefore,nomethodoftestingisprovidedforthepresentdocument.2ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublicationand/oreditionnumberorversionnumber)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.[1]ITU-TRecommendationI.130(1988):"MethodforthecharacterizationoftelecommunicationservicessupportedbyanISDNandnetworkcapabilitiesofanISDN".[2]ITU-TRecommendationI.112(1993):"VocabularyoftermsforISDNs".[3]ITU-TRecommendationE.164(1997):"Theinternationalpublictelecommunicationnumberingplan".[4]ITU-TRecommendationI.210(1993):"PrinciplesoftelecommunicationservicessupportedbyanISDNandthemeanstodescribethem".[5]ETSIETS300345:"IntegratedServicesDigitalNetwork(ISDN);InterworkingbetweenpublicISDNsandprivateISDNsfortheprovisionoftelecommunicationservices;Generalaspects".SIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)73Definitionsandabbreviations3.1DefinitionsForthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply:address:seeITU-TRecommendationE.164[3],clauseB.3.2basicaccess:seeITU-TRecommendationI.112[2],clause2.4,definition425basiccallprocedures:proceduresbywhichacall(asaninstanceofabasictelecommunicationservice)isestablishedandterminated(basic)service;Telecommunicationsservice:seeITU-TRecommendationI.112[2],clause2.2,definition201(call)forwarding:generaltermappliedtoanyfunctionalitywherebyacallisredirectedautomaticallybytheserviceprovidertoanotheruser.Theformsofforwardingare:unconditional,wherebyallcallsareredirected;busy,wherebycallsencounteringbusyareredirected;and,noreply,wherebycallswhicharenotansweredwithinatimeperiodareredirecteddiversion:generaltermwhichincludesallformsofforwarding,andincludesdeflectionwherebycallsareredirectedbytheuserinsteadofbeinganswereddiverted-touser:usertowhomacallisredirectedasaresultofdiversiondivertinguser:userforwhomthecallissubjectedtodiversionforwarded-touser:usertowhomthecallisredirectedasaresultofforwardingIntegratedServicesDigitalNetwork(ISDN):seeITU-TRecommendationI.112[2],clause2.3,definition308ISDNnumber:numberconformingtothenumberingplanandstructurespecifiedinITU-TRecommendationE.164[3]primaryrateaccess:seeITU-TRecommendationI.112[2],clause2.4,definition426serveduser:usertowhomtheCFNRsupplementaryserviceisprovidedsub-address:seeITU-TRecommendationE.164[3],clauseB.3.3supplementaryservice:seeITU-TRecommendationI.210[4],clause2.4userA:callinguserinacallwhichissubjecttodiversionuserB:serveduserwhenacall(fromuserA)issubjecttotheCFNRsupplementaryserviceNOTE:Inthecontextofmultiplediversions,asuffixisused,e.g.1,2,.n,n+1,.m,todenotethesuccessivedivertingusers.Forexample,userB3isalsothediverted-touserwithrespecttothediversionappliedatuserB2.userC:forwarded-touserinacallwhichissubjecttotheCFNRsupplementaryservice.Inthecaseofacallwhichissubjecttomultiplediversions,userCistheforwarded-touserwithrespecttothefinalcallforwarding3.2AbbreviationsForthepurposesofthepresentdocument,thefollowingabbreviationsapply:CFNRCallForwardingNoReplyISDNIntegratedServicesDigitalNetworkPSTNPublicSwitchedTelephoneNetworkSIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)84DescriptionTheCFNRsupplementaryserviceshallbeavailabletouserswhoareconnectedtothenetworkviaabasicaccessoraprimaryrateaccess.TheCFNRsupplementaryserviceenablesaservedusertohavethenetworkredirecttoanotherusercallswhichareaddressedtotheserveduser'sISDNnumber,andforwhichtheconnectionisnotestablishedwithinadefinedperiodoftime.TheCFNRsupplementaryservicemayoperateonallcalls,orjustthoseassociatedwithspecifiedbasicservices.Theserveduser'sabilitytooriginatecallsisunaffectedbytheCFNRsupplementaryservice.TheCFNRsupplementaryservicecanonlybeinvokedbythenetworkafterthecallhasbeenofferedtotheserveduserandanindicationthatthecalleduserisbeinginformedofthecallhasbeenreceived.Asaserviceprovideroption,asubscriptionoptioncanbeprovidedtoenabletheservedusertoreceiveanindicationthattheCFNRsupplementaryservicehasbeenactivated.ThisindicationshallbeprovidedwhentheserveduseroriginatesacalliftheCFNRsupplementaryservicehasbeenactivatedfortheserveduser'sISDNnumberandforthebasicservicerequestedforthecall.Themaximumnumberofdiversionspermittedforeachcallisaserviceprovideroptionwithanupperlimitoffivediversions.Whencountingthenumberofdiversions,alltypesofdiversionareincluded.5Procedures5.1ProvisionandwithdrawalTheCFNRsupplementaryserviceshallbeprovidedafterpriorarrangementwiththeserviceprovider.Asaserviceprovideroption,theCFNRsupplementaryservicecanbeprovidedonaperISDNnumberbasis,ortheCFNRsupplementaryservicecanapplytothewholeaccess.Ifaserviceprovideroffersbothoftheseoptions,thenitshallbeasubscriptionoptiontochoosewhichoftheseoptionsapplies.Inaddition,theCFNRsupplementaryservice(includingoptions)canbesubscribedtoforallbasicservicessubscribedtobytheuser,orasaserviceprovideroption,theusercanidentifyparticularbasicservice(s)forwhichtheCFNRsupplementaryserviceshallapply.Asaserviceprovideroption,theservicecanbeofferedwithoneormoreoffoursubscriptionoptions,whichcanapplyseparatelytoeachbasicservicesubscribedto.IftheCFNRsupplementaryserviceisprovidedonaperISDNnumberbasis,thentheseoptionscanapplyseparatelytoeachISDNnumber.Foreachsubscriptionoption,onlyonevaluecanbeselected.Subscriptionoptionsaresummarizedintable1.Table1SubscriptionoptionsValueServeduserreceivesnotificationthatthecallhasbeenforwarded-no-yesCallinguserreceivesnotificationthatthecallhasbeenforwarded-no-yes,withouttheISDNnumberoftheforwarded-touser-yes,withtheISDNnumberoftheforwarded-touserServeduserreceivesnotificationthattheCFNRsupplementaryserviceiscurrentlyactivated-no-yesTheservedusersISDNnumbercanbepresentedtotheforwarded-touser-no-yesSIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)9Asaserviceprovideroption,thevalueofthenoreplytimershallbeabletobechangedbytheserveduserbymeansofasubscriberprocedure.Asaserviceprovideroption,asubscriptionoptioncanbeofferedtoservedusers,toenabletheCFNRsupplementaryservicetobeactivated,deactivatedandinterrogatedforallISDNnumbersonthesameaccess.ISDNnumbersforwhichtheCFNRsupplementaryserviceisnotsubscribedtoshallnotbeaffected.TheCFNRsupplementaryserviceshallbewithdrawnbytheserviceprovideruponrequestofthesubscriberorforserviceproviderreasons.5.2Normalprocedures5.2.1RegistrationanderasureRegistrationofinformationisperformedonactivationoftheCFNRsupplementaryservice.TherearenoseparateregistrationproceduresfortheCFNRsupplementaryservice.5.2.2Activationanddeactivation5.2.2.1ActivationTheservedusershallsupplythefollowinginformationwhenrequestingtheactivationoftheCFNRsupplementaryservice:-theISDNnumberoftheforwarded-touser,whichcanbeaccompaniedbyasub-addressforadditionalidentificationoftheforwarded-touser;and-informationastowhethertheactivationoftheCFNRsupplementaryserviceisforallbasicservicestowhichtheCFNRsupplementaryserviceapplies,orforaspecificbasicserviceoutofthebasicservicestowhichtheCFNRsupplementaryserviceapplies;and-thevalueinsecondsofthenoreplytimer,ifdifferentfromthepresentvalue.(Maximumvalue180seconds.).WhensubscriptionappliesonaperISDNnumberbasisandmorethanoneISDNnumberisallocatedtotheaccess,then:-theservedusershallalsosupplytheISDNnumberforwhichtheactivationoftheCFNRsupplementaryserviceshallapply;or-asaserviceprovideroption,theservedusercan,ifsubscribedto,indicatethattheactivationoftheCFNRsupplementaryserviceshallapplyforallISDNnumbersforwhichtheCFNRsupplementaryserviceissubscribedto.Inthiscase,thisactivationshallreplaceanypreviousactivationoftheCFNRsupplementaryservicewhichmaybeinforceonindividualISDNnumbersontheaccess,forthebasicservicesindicatedatactivation.Whensubscriptionappliesforthewholeaccess,oronlyoneISDNnumberisallocatedtotheaccess,theserveduserneednotprovideanISDNnumbertoidentifytheserveduser.IftheserveduserincludesanISDNnumberallocatedtothataccess,orindicatesthattheactivationoftheCFNRsupplementaryserviceshallapplytoallISDNnumbers(ifthisfunctionalityisofferedbytheserviceproviderandsubscribedtobytheserveduser)thentheISDNnumber,ortheindicationofallISDNnumbers,shallbeignored.ActivationoftheCFNRsupplementaryserviceshallproceedasnormal.TheservedusercanseparatelyactivatetheCFNRsupplementaryserviceforeachbasicservicetowhichtheCFNRsupplementaryserviceappliesandtherebyrequestadifferentISDNnumberand/orsub-addresstoidentifytheforwarded-touserforeachbasicservicetowhichtheCFNRsupplementaryserviceapplies.WhentheCFNRsupplementaryserviceisactivatedforallbasicservices,thisactivationshallreplaceanypreviousactivationoftheCFNRsupplementaryservicewhichmaybeinforceonindividualbasicservices.SIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)10VerificationoftheISDNnumberoftheforwarded-tousercanbecarriedoutbeforeacceptingtherequesttoactivatetheCFNRsupplementaryservice.Thisverificationcanbelimited,e.g.asimplecheckoftheISDNnumberoftheforwarded-tousertoseeiftheISDNnumberiswithintheallowednumberrange.Whentheserveduser'srequesttoactivatetheCFNRsupplementaryserviceisaccepted,theserviceprovidershallinformtheserveduser.Theinformationshallincludetheaddressoftheforwarded-tousertowhomtheserveduserhasactivatedtheCFNRsupplementaryservice.Allaffectedusersshallbeinformed.5.2.2.2DeactivationTheCFNRsupplementaryservicecanbedeactivatedinanyofthefollowingways:-theservedusercanrequestthedeactivationoftheCFNRsupplementaryserviceforindividualbasicservices.TheserviceprovidershallinformtheserveduserthatthepreviousactivationoftheCFNRsupplementaryservicehasbeendeactivated.Allaffectedusersshallbeinformed;-theservedusercanrequestthedeactivationoftheCFNRsupplementaryserviceforallbasicservices.TheserviceprovidershallinformtheserveduserthatthepreviousactivationoftheCFNRsupplementaryservicehasbeendeactivated.Allaffectedusersshallbeinformed;-theservedusercanrequesttheactivationoftheCFNRsupplementaryserviceindicatingabasicserviceforwhichtheCFNRsupplementaryservicehasalreadybeenactivated.Thisshallreplacethepreviousinformationregisteredforthatbasicservice.Inthiscase,usersshallnotbespecificallyinformedofthedeactivation.Theproceduresofclause5.2.2.1forinformingtheserveduserapply;-theservedusercanrequesttheactivationoftheCFNRsupplementaryserviceforallbasicservices.ThisshallreplacetheinformationregisteredforallofthebasicservicesforwhichtheCFNRsupplementaryservicehasalreadybeenactivated.Inthiscase,usersshallnotbespecificallyinformedofthedeactivation.Theproceduresofclause5.2.2.1forinformingtheserveduserapply.WhensubscriptionappliesonaperISDNnumberbasisandmorethanoneISDNnumberisallocatedtotheaccess,then:-theservedusershallalsosupplytheISDNnumberforwhichthedeactivationoftheCFNRsupplementaryserviceshallapply;or-asaserviceprovideroption,theservedusercan,ifsubscribedto,indicatethatthedeactivationoftheCFNRsupplementaryserviceshallapplyforallISDNnumbersforwhichtheCFNRsupplementaryserviceissubscribedto.Whensubscriptionappliesforthewholeaccess,oronlyoneISDNnumberisallocatedtotheaccess,theserveduserneednotprovideanISDNnumbertoidentifytheserveduser.IftheserveduserincludesanISDNnumberallocatedtothataccess,orindicatesthatthedeactivationoftheCFNRsupplementaryserviceshallapplytoallISDNnumbers(ifthisfunctionalityisofferedbytheserviceproviderandsubscribedtobytheserveduser)thentheISDNnumber,ortheindicationofallISDNnumbers,shallbeignored.DeactivationoftheCFNRsupplementaryserviceshallproceedasnormal.5.2.3InvocationandoperationThemaximumnumberofdiversionsforeachcallshallbelimited.Themaximumnumberofdiversionsisaserviceprovideroptionwithanupperlimitoffivediversionsforeachcall.Whencountingthenumberofdiversions,alltypesofdiversionsshallbeincluded.SIST EN 300 201 V1.2.1:2004



ETSIETSIEN300201V1.2.1(2001-05)115.2.3.1Serveduser'sviewIftheCFNRsupplementaryservicehasbeenactivated,theniftheconnectionisnotestablishedwithinaspecifiedtimeintervalaftertheserveduserhasbeeninformedofthecall,thentheserviceprovidershallattempttoforwardthecall.Thecallshallbeofferedtotheserveduserbymeansofbasiccallprocedures.Accordingtothevalueofasubscriptionoption,theservedusershallbeinformedthattheCFNRsupplementaryservicehasbeeninvokedonthecall.Thisinformationshallbegivenwhenthenetworkoriginatesthecalltotheforwarded-touser.WhentheCFNRsupplementaryserviceisinvoked,thenetworkshallsetupacalltotheforwarded-touser.Accordingtoanetworkoption,oneofthefollowingshalloccur:a)thecalltotheservedusershallberetaineduntilthenetworkreceivesanindicationthattheforwarded-touserisbeinginformedofthecall,orthattheconnectionisestablishedattheforwarded-touser,whereuponthecallshallberemovedfromtheserveduser.If,onamultipointaccess,anotherterminalrequeststheestablishmentoftheconnectionpriortotheremovalofthecall,thentheconnectionshallbeestablishedandtheforwardingceased;orb)thecallshallberemovedfromtheserveduserwhentheCFNRsupplementaryserviceisinvoked.5.2.3.2Forwarded-touser'sviewTheforwarded-tousershallreceiveanindicationthattheCFNRsupplementaryservicehasbeeninvokedonthecall.Dependingonthevalueofoneoftheserveduser'ssubscriptionoptionstheforwarded-tousercanalsoreceivetheISDNnumberoftheserveduser.Ifmultiplediversionshaveoccurred,thentheforwarded-tousercanalsobegiventheoriginallycalleduser'sISDNnumberprovidedthatthepresentationhasbeenpermittedbythediversionserviceinvokedfortheoriginallycalleduser.Whenmultiplediversionsoccurthereasonforforwardinggiventotheforwarded-tousershallindicatethelasttypeofforwarding(i.e.theinvocationoftheCFNRsupplementaryservice).5.2.3.3Callinguser'sviewDependingonthevalueoftheserveduser'ssubscriptionoption"callinguserreceivesnotificationthatthecallhasbeenforwarded",userAcanbegivenanindicationthatthecallisbeingforwarded.Inthatcase,thisinformationshallbegivenwhenthenetworkoriginatesthecalltotheforwarded-touser.Dependingonthevalueofthissubscriptionoption,userAcanalsobegiventheISDNnumberoftheforwarded-touser.Whencallsareforwardedonce,i.e.duetoasingleinvocationoftheCFNRsupplementaryservice,thefollowinginformationshallbegiventouserAbasedonthevalueoftheserveduser'ssubscriptionoption"callinguserreceivesnotificationthatthecallhasbeenforwarded":-ifthevalueofthesubscriptionoptionis"no",thennoinformationshallbesenttouserA;-ifthevalueofthesubscriptionoptionis"yes,withouttheISDNnumberoftheforwarded-t
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