SIST EN 301 479 V1.1.2:2005

• Abstract:

  Stage 1 description of the supplementary service: Line hunting

• 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 301 479 V1.1.2 (2000-08) - Integrated Services Digital Network (ISDN); Line Hunting (LH) supplementary service; Service description

SIST EN 301 479 V1.1.2:2005 is the Slovenian adoption of ETSI EN 301 479 V1.1.2 for Integrated Services Digital Network (ISDN) Line Hunting (LH). It specifies the Stage 1 service description of the LH supplementary service, which means the overall user-visible behavior of the service and its use on ISDN access arrangements.

What does SIST EN 301 479 V1.1.2:2005 specify?

SIST EN 301 479 V1.1.2:2005 defines how ISDN Line Hunting works from the user’s point of view. It covers the service on accesses at the S/T reference point, the interworking of private ISDNs with the public ISDN, and the base functionality when the service is provided through a private ISDN.

The document is organized into scope, references, definitions, abbreviations, description, procedures, intercommunication considerations, interaction with other supplementary services, interaction with other services, and one informative annex.

Annex	What it covers
Annex A	Consideration of a Multi-Nodal Line Hunting service

The standard applies to circuit-switched telecommunications services, except services that require more than one B-channel. It also states that it does not specify charging principles or a testing method for the service.

What are the key requirements of SIST EN 301 479 V1.1.2:2005?

SIST EN 301 479 V1.1.2:2005 sets out the service rules for hunt groups, access selection, withdrawal, and interaction with related supplementary services. In practice, it tells the network how calls to a hunt group number are offered to free accesses and how special cases are handled.

Hunt group structure and access rules

Clause 5 says the service is intended for accesses at the S/T reference point and can be provided over basic access and, as a network operator option, primary rate access. A hunt group can contain basic accesses, primary rate accesses, or both, but an access may belong to only one hunt group. This matters because the subscriber must plan the access group and terminal arrangement accordingly.

The serving user can set how many B-channels are available for the hunt group on each access. A call may be presented to an access only if the configured number of used B-channels would not be exceeded. In practice, this prevents overloading an access beyond the subscribed capacity.

Selection method and withdrawal

Clause 6 allows two selection methods: sequential hunting and cyclic hunting. Sequential hunting starts at the same access each time, while cyclic hunting starts from the next access after the one used last. This affects how calls distribute across the group and how evenly the load is shared.

The service also supports hunt group withdrawal where subscribed. An access can temporarily stop receiving hunt group calls, and the user can later cancel that withdrawal. If withdrawal is supported, the user may receive an indication when the access is withdrawn. This is useful for maintenance or when a terminal position should not take incoming hunt-group calls.

Invocation and busy handling

The network automatically invokes LH when a call arrives to the hunt group number. If a free access exists, it presents the call and indicates the hunt group number as the called party number. If no free access is available, or if all accesses are withdrawn, the call is treated as busy according to the basic call procedures. That means the call is not left in an undefined state - the calling side gets a normal busy outcome.

Interaction with related supplementary services

Clause 8 gives the main interaction rules. Some services, such as call forwarding unconditional and selective call forwarding, can take precedence over LH in the cases stated. CCBS and CCNR can be activated toward a hunt group or toward the individual access identified by its individual number, but not toward the hunt group number itself.

Several other supplementary services are listed as having no impact on LH, including call hold, explicit call transfer, freephone, malicious call identification, subaddressing, three-party, and user-to-user signalling. This helps implementers know where LH changes call handling and where it does not.

Remote control and multi-node considerations

Clause 9 states that LH can be remotely controlled, using the access identity to identify the access within a hunt group. Annex A then considers a multi-nodal Line Hunting service as an informative discussion of how LH might be used across multiple nodes.

What terms does SIST EN 301 479 V1.1.2:2005 define?

LH means Line Hunting, the supplementary service that offers a call to a free access within a hunt group.

hunt group is the set of accesses over which the LH supplementary service applies for the assigned ISDN number.

access identity identifies one access within a hunt group by combining the hunt group number and a sequence number.

free access is an access to which the call can be offered without exceeding the number of used B-channels set for that access.

hunt group withdrawal is the request to temporarily prevent an access from receiving hunt group calls.

sequential hunting means the search starts at the same access each time and follows a fixed order until a free access is found or all have been checked.

cyclic hunting means the search starts at the next access after the last one used and then follows a fixed order.

BA means Basic Access, and PRA means Primary Rate Access.

Who uses SIST EN 301 479 V1.1.2:2005?

SIST EN 301 479 V1.1.2:2005 is used by ISDN service providers, network operators, and equipment implementers that support hunt groups on public or private ISDN. It is also relevant to telecom engineers and administrators who configure access groups, B-channel availability, hunt group withdrawal, and related supplementary services.

For buyers and quality managers, it helps identify whether an ISDN implementation supports group numbering, access selection, interworking, and the interaction rules that matter in real installations with several terminals on one number.

Which standards are used with SIST EN 301 479 V1.1.2:2005?

Clause 2 and the definitions rely on these referenced standards and parts:

• CCITT Recommendation I.130 - the three-stage method used to describe telecommunications services.
• ITU-T Recommendation I.112 - vocabulary and core ISDN terms such as ISDN, basic access, and primary rate access.
• ITU-T Recommendation I.210 - the concept of supplementary service.
• ITU-T Recommendation E.164 - numbering plan and structure for ISDN numbers.
• ITU-T Recommendation I.221 - common service characteristics, including user busy concepts.
• ETSI EN 300 089 - Calling Line Identification Presentation (CLIP), including the default number concept.
• ETSI EN 301 484-1 - DSS1 protocol specification for the LH supplementary service.
• ETSI ETS 300 356 - ISUP version 2 for the international interface.

What does the SIST EN 301 479 V1.1.2:2005 document contain?

The document contains a user-level service description, procedural rules for provision, activation, withdrawal, invocation, interrogation, and exceptional handling, plus detailed interaction rules with other supplementary services and services. It also includes tables for subscription options, especially for the whole hunt group and for each access.

Annex A adds guidance on a multi-nodal Line Hunting service and explains issues such as hunt group withdrawal and call handling when no free access is available at a local node. The bibliography cites ITU-T Recommendation I.411 as supporting information for ISDN user-network reference configurations.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Digitalno omrežje z integriranimi storitvami (ISDN) – Dopolnilna storitev: iskanje voda v skupini (LH) – Opis storitveIntegrated Services Digital Network (ISDN); Line Hunting (LH) supplementary service; Service description33.080Digitalno omrežje z integriranimi storitvami (ISDN)Integrated Services Digital Network (ISDN)ICS:Ta slovenski standard je istoveten z:EN 301 479 Version 1.1.2SIST EN 301 479 V1.1.2:2005en01-januar-2005SIST EN 301 479 V1.1.2:2005SLOVENSKI
STANDARD
ETSIEN301479V1.1.2(2000-08)EuropeanStandard(Telecommunicationsseries)IntegratedServicesDigitalNetwork(ISDN);LineHunting(LH)supplementaryservice;ServicedescriptionSIST EN 301 479 V1.1.2:2005

ETSIETSIEN301479V1.1.2(2000-08)2ReferenceDEN/SPAN-020003KeywordsISDN,LH,stage1,supplementaryserviceETSI650RoutedesLuciolesF-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 301 479 V1.1.2:2005

ETSIETSIEN301479V1.1.2(2000-08)3ContentsIntellectualPropertyRights.5Foreword.51Scope.62References.63Definitions.74Abbreviations.85Description.86Procedures.96.1Provisionandwithdrawal.96.2Normalprocedures.106.2.1Activation,deactivationandregistration.106.2.2Erasure.106.2.3Invocationandoperation.106.2.4Interrogation.106.3Exceptionalprocedures.106.3.1Activation,deactivationandregistration.106.3.2Erasure.116.3.3Invocationandoperation.116.3.4Interrogation.117Intercommunicationconsiderations.117.1Interworkingwithnon-lSDNs.117.2InterworkingwithprivateISDNs.118Interactionwithothersupplementaryservices.118.1Adviceofchargeservices.128.1.1Adviceofchargeatcallset-uptime.128.1.2Adviceofchargeduringthecall.128.1.3Adviceofchargeattheendofacall.128.2Callwaiting.128.3Callhold.128.4Explicitcalltransfer.128.5Numberidentificationservices.138.5.1Callinglineidentificationpresentation.138.5.2Callinglineidentificationrestriction.138.5.3Connectedlineidentificationpresentation.138.5.4Connectedlineidentificationrestriction.138.6Closedusergroup.138.7Callcompletionservices.138.7.1Completionofcallstobusysubscriber.138.7.2Completionofcallsonnoreply.138.8Conferenceservices.148.8.1Conferencecall,add-on.148.8.2Conferencecall,meet-me.148.9Directdiallingin.148.10Diversionservices.148.10.1Callforwardingunconditional.148.10.2Callforwardingbusy.148.10.3Callforwardingnoreply.148.10.4Calldeflection.148.10.5Selectivecallforwarding.148.11Freephone.158.12Maliciouscallidentification.15SIST EN 301 479 V1.1.2:2005

ETSIETSIEN301479V1.1.2(2000-08)48.13Multiplesubscribernumber.158.14Subaddressing.158.15Terminalportability.158.16Threeparty.158.17User-to-usersignalling.158.18Huntingservices.158.18.1Linehunting.158.18.2Trunkhunting.168.19Callbarringservices.168.19.1Outgoingcallbarring-fixed.168.19.2Outgoingcallbarring-usercontrolled.169Interactionwithotherservices.169.1Universalaccessnumber.169.2Virtualcardcalling.169.3Premiumrate.169.4Universalpersonaltelecommunication.169.5Remotecontrol.16AnnexA(informative):ConsiderationofaMulti-NodalLineHuntingservice.17Bibliography.18History.19SIST EN 301 479 V1.1.2:2005

ETSIETSIEN301479V1.1.2(2000-08)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).InaccordancewithCCITTRecommendationI.130[1],thefollowingthreelevelstructureisusedtodescribethesupplementarytelecommunicationsservicesasprovidedbyEuropeanpublictelecommunicationsoperatorsunderthepan-EuropeanIntegratedServicesDigitalNetwork(ISDN):Stage1:isanoverallservicedescription,fromtheuser'sstandpoint;Stage2:identifiesthefunctionalcapabilitiesandinformationflowsneededtosupporttheservicedescribedinstage1;andStage3:definesthesignallingsystemprotocolsandswitchingfunctionsneededtoimplementtheservicedescribedinstage1.Thepresentdocumentdetailsthestage1aspects(overallservicedescription)fortheLineHunting(LH)supplementaryservice.Stage2willbespecifiedlaterintheETS300356[8]series.Stage3aspectsaredetailedinEN301484-1[7].NationaltranspositiondatesDateofadoptionofthisEN:25August2000DateoflatestannouncementofthisEN(doa):30November2000DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):31May2001DateofwithdrawalofanyconflictingNationalStandard(dow):31May2001SIST EN 301 479 V1.1.2:2005

ETSIETSIEN301479V1.1.2(2000-08)61ScopeThepresentdocumentdefinesthestageoneoftheLineHunting(LH)supplementaryserviceforthepan-EuropeanIntegratedServicesDigitalNetwork(ISDN)asprovidedbyEuropeanpublictelecommunicationsoperators.Stageoneisanoverallservicedescriptionfromtheuser'spointofview(seeCCITTRecommendationI.130[1]),butdoesnotdealwiththedetailsofthehumaninterfaceitself.ThepresentdocumentdefinestheinterworkingrequirementsofprivateISDNswiththepublicISDN.InadditionthepresentdocumentspecifiesthebasefunctionalitywheretheserviceisprovidedtotheuserbyaprivateISDN.ThepresentdocumentdoesnotspecifytheadditionalrequirementswheretheserviceisprovidedtotheuserviaatelecommunicationsnetworkthatisnotanISDNbutdoesincludeinterworkingrequirementsofothernetworkswiththepublicISDN.Interactionswith(supplementary)servicesnotlistedinclauses8and9areoutsidethescopeofthepresentdocument.Chargingprinciplesareoutsidethescopeofthepresentdocument.TheLHsupplementaryserviceenablescallstoasingleISDNnumbertobeofferedtoafreeaccessinagroupofaccessestowhichterminalsareconnectedtoanend-user'smultipleaccessgroup(S/Treferencepoint).Theprinciplesfortheselectionofafreechannelwithinanaccessareanetworkprovidermatteraspartofthebasiccallproceduresandsoareoutsidethescopeofthepresentdocument.TheLHsupplementaryserviceisapplicabletoallcircuit-switchedtelecommunicationsserviceswiththeexceptionofservicesrequiringtheuseofmorethanoneB-channel.ThepresentdocumentisapplicabletothestagetwoandstagethreestandardsfortheISDNLHsupplementaryservice.Theterms"stagetwo"and"stagethree"arealsodefinedinCCITTRecommendationI.130[1].Wherethetextindicatesthestatusofarequirement,(i.e.asstrictcommandorprohibition,asauthorizationleavingfreedom,asacapabilityorpossibility),thisshallbereflectedinthetextoftherelevantstagetwoandstagethreestandards.Furthermore,conformancetothepresentdocumentismetbyconformingtothestagethreestandardswiththefieldofapplicationappropriatetotheequipmentbeingimplemented.Thereforenomethodoftestingisprovidedforthepresentdocument.2ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.• Anon-specificreferencetoanETSshallalsobetakentorefertolaterversionspublishedasanENwiththesamenumber.[1]CCITTRecommendationI.130(1988):"MethodforthecharacterizationoftelecommunicationservicessupportedbyanISDNandnetworkcapabilitiesofanISDN".[2]ITU-TRecommendationI.112(1993):"VocabularyoftermsforISDNs".[3]ITU-TRecommendationI.210(1993):"PrinciplesoftelecommunicationservicessupportedbyanISDNandthemeanstodescribethem".SIST EN 301 479 V1.1.2:2005

ETSIETSIEN301479V1.1.2(2000-08)7[4]ITU-TRecommendationE.164(1997):"Theinternationalpublictelecommunicationnumberingplan".[5]ITU-TRecommendationI.221(1993):"Commonspecificcharacteristicsofservices".[6]ETSIEN300089:"IntegratedServicesDigitalNetwork(ISDN);CallingLineIdentificationPresentation(CLIP)supplementaryservice;Servicedescription".[7]ETSIEN301484-1:"IntegratedServicesDigitalNetwork(ISDN);LineHunting(LH)supplementaryservice;DigitalSubscriberSignallingSystemNo.one(DSS1);Part1:Protocolspecification".[8]ETSIETS300356:"IntegratedServicesDigitalNetwork(ISDN);SignallingSystemNo.7;ISDNUserPart(ISUP)version2fortheinternationalinterface".3DefinitionsForthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply:access:generalterm,usedinthepresentdocument,denotingbasicaccessesandasanetworkprovideroption,primaryrateaccessesaccessidentity:meansofidentifyinganindividualaccessbelongingtoahuntgroup;theaccessidentityconsistsofthehuntgroupnumberplusasequencenumberidentifyingtheindividualaccesswithinthehuntgroupIntegratedServicesDigitalNetwork(ISDN):seeITU-TRecommendationI.112[2],subclause2.3,definition308service;telecommunicationsservice:seeITU-TRecommendationI.112[2],subclause2.2,definition201supplementaryservice:seeITU-TRecommendationI.210[3],subclause2.4ISDNnumber:numberconformingtothenumberingplanandstructurespecifiedinITU-TRecommendationE.164[4]basicaccess:seeITU-TRecommendationI.112[2],subclause2.4,definition425primaryrateaccess:seeITU-TRecommendationI.112[2],subclause2.4,definition426freeaccess:accesstowhichthecallcanbeofferedwithoutexceedingthenumberofusedB-channelsspecifiedforthisaccesshuntgroup:numberofaccessesoverwhichtheLHsupplementaryserviceappliesfortheassignedISDNnumber.Ahuntgroupmayconsistofasingleaccesshuntgroupnumber:ISDNnumber,towhichtheLHsupplementaryserviceisallocatedandtowhichISDNbasicservicesandsupplementaryservicesrelatingtothehuntgroupareallocated.huntgroupwithdrawal:requestbyanaccessofthehuntgroupinordertotemporarilypreventthisaccessfromreceivingcallstothehuntgroup(existingcallsarenotaffected)individualnumber:(inthecontextofthepresentdocument)ISDNnumberwhichisnotahuntgroupnumber,butwhichcanbeassociatedwithanaccessthatbelongstoahuntgroupinordertoidentifyoneormoreterminalsconnectedtotheaccessserveduser:usertowhomtheLHsupplementaryserviceisprovidedbasiccallprocedures:proceduresbywhichacall(asaninstanceofabasictelecommunicationsservice)isestablishedandterminatednetworkdetermineduserbusy:seeITU-TRecommendationI.221[5],subclause2.1.4userdetermineduserbusy:seeITU-TRecommendationI.221[5],subclause2.1.4sequentialhunting:selectionofafreeaccessalwaysstartswiththesameaccessandthenfollowsafixedorderuntilallaccessesinthehuntgrouphavebeensearchedorafreeaccessisfoundSIST EN 301 479 V1.1.2:2005

ETSIETSIEN301479V1.1.2(2000-08)8cyclichunting:selectionofafreeaccessalwaysstartsatthenextaccessaftertheoneusedlast,andfollowsafixedorder.Whenthelastaccessinthegroupisreached,thesearchcontinuesfromthebeginningofthegroupuntilallaccessesinthegrouphavebeensearcheddefaultnumber:definedfortheCLIPserviceinEN300089[6]Inordertoprovideconsistencyfromacustomerperspectivethesamedefaultnumbermaybeassociatedwithalltheaccessesthatgotoauserinstallation.InthissituationthedefaultnumberisaHuntGroupNumberandtheHuntGroupitrelatestocontainsalltheaccessesthatgotoauserinstallation.end-user:userwhoisconnec
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