SIST EN 301 484-1 V1.1.1:2005

• Abstract:

  The Line Hunting supplementary service enables calls to a single ISDN number to be offered to a free access in a group of basic accesses. The Line Hunting supplementary service is intended for use on accesses to which terminals are connected at the S/T references point

• 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 301 484-1 V1.1.1 (2000-04) - Integrated Services Digital Network (ISDN); Line Hunting (LH) supplementary service; Digital Subscriber Signalling System No. one (DSS1); Part 1: Protocol specification

SIST EN 301 484-1 V1.1.1:2005 is the Slovenian adoption of ETSI EN 301 484-1 V1.1.1, published by SIST. It specifies the stage 3 protocol for the Line Hunting (LH) supplementary service on ISDN using DSS1, so it is aimed at people who implement, operate, or test hunt-group calling at the user-network interface.

What does SIST EN 301 484-1 V1.1.1:2005 specify?

SIST EN 301 484-1 V1.1.1:2005 specifies the protocol procedures and switching functions for the LH supplementary service at the T reference point or coincident S/T reference point. In practice, it tells an ISDN network how to present calls to a free access in a hunt group, and how the served user can withdraw, cancel withdrawal, or interrogate the access status.

The scope focuses on circuit-switched telecommunication services, except services that need more than one B-channel. It also leaves the selection of a free channel within an access to the network provider as part of the basic call procedures.

The document is organized into clauses on scope, references, definitions, abbreviations, service description, operational requirements, coding requirements, state definitions, signalling procedures, interworking, interactions, timer values, and SDL diagrams. Annex A gives signalling flows.

What are the key requirements of SIST EN 301 484-1 V1.1.1:2005?

• Provision and withdrawal - Clause 6 says the LH supplementary service is provided by prior arrangement with the network provider and withdrawn on request by the network provider or subscriber. Practically, provisioning needs the hunt group number and the list of accesses.

• Hunt group setup and subscription options - Clause 6 defines options for each hunt group and each access, including the selection method, the number of B-channels available for the hunt group, activation allowance, temporary hunt-group withdrawal, and user notification. This matters because the service behavior depends on what each access is subscribed to.

• Access membership rules - The description in Clause 5 states that an access can belong to only one hunt group, and the hunt group may contain basic accesses, primary rate accesses, or both. That matters for network design and number assignment.

• Call presentation and busy handling - Clause 9 says the network automatically invokes LH on calls to a hunt group number and selects a free access according to sequential or cyclic hunting. If no free access is available, or if all accesses are withdrawn, the hunt group is treated as network determined user busy.

• Temporary withdrawal, cancellation, and interrogation - Clause 9 defines the user procedures for WithdrawLHG, CancelWithdrawLHG, and InterrogationLHG. Each procedure uses invoke, return result, return error, or reject components and a timer. In practice, implementers must support the request/response behavior and handle timeout or error cases.

• Timer values - Clause 13 sets T-WITHDRAWAL, T-CANCELLATION, and T-INTERROGATE to 4 seconds. This is important for interworking and test cases because a delayed response is treated as failure.

• Facility information element coding - Clause 7 requires all LH components to be carried in a Facility information element, using the operation and error definitions given there. That is the key coding rule for DSS1 message implementation.

• User notification on withdrawal - Clause 9.3 says that if the option applies, the network includes a withdrawnFromLHG invoke component in the first call control message when a withdrawn access originates a call. This lets the user know the access is currently withdrawn from the hunt group.

What terms does SIST EN 301 484-1 V1.1.1:2005 define?

• Line Hunting (LH) - The supplementary service that offers calls to a single ISDN number to a free access in a hunt group.
• Hunt group - The set of accesses over which the LH supplementary service applies for one hunt group number.
• Free access - An access that can receive the call without exceeding its configured number of used B-channels.
• Hunt group withdrawal - A request to temporarily stop an access from receiving calls to the hunt group.
• Sequential hunting - A selection method that starts from a fixed access and continues in order.
• Cyclic hunting - A selection method that starts after the last used access and wraps around through the group.
• User determined user busy - The user-busy condition that can result when call presentation to an access fails.

Who uses SIST EN 301 484-1 V1.1.1:2005?

ISDN network operators use this standard to configure hunt groups, call presentation rules, and withdrawal behavior. Switch and signalling equipment vendors use it to implement DSS1 procedures, Facility information element coding, and state handling.

Test laboratories and conformance teams use it together with the later parts of EN 301 484 to build test cases and verify interoperability. Quality managers and buyers use it to check whether an implementation supports LH on ISDN access lines, including withdrawal, interrogation, and busy handling.

Which standards are used with SIST EN 301 484-1 V1.1.1:2005?

• EN 301 479 - Service description and stage 1 aspects of LH.
• EN 300 195-1 - Interactions with other supplementary services.
• EN 300 196-1 - Generic functional protocol for supplementary services, including Facility information element coding rules.
• EN 300 403-1 - DSS1 basic call control procedures used together with LH.
• ITU-T I.112, I.210, I.130, I.411, I.221 - Definitions, service principles, characterization method, reference configurations, and user-busy concepts.
• ITU-T E.164, X.680, X.880, Z.100 - Numbering plan, ASN.1, remote operations, and SDL notation.

What does the SIST EN 301 484-1 V1.1.1:2005 document contain?

Clause 6 contains network options tables that show how the service can be configured. Clause 7 gives the ASN.1 operation and error definitions for WithdrawLHG, CancelWithdrawLHG, InterrogationLHG, and the related status response.

Clause 8 defines the user and network states, and Clause 9 gives the signaling procedures for normal and exceptional cases. Clause 13 lists the timer values, and Clause 14 specifies SDL diagrams for the procedures.

Annex A gives signalling flow figures for successful temporary withdrawal, successful cancellation, and successful interrogation. These figures are used when implementing or testing the message sequences on DSS1.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Integrated Services Digital Network (ISDN); Line Hunting (LH) supplementary service; Digital Subscriber Signalling System No. one (DSS1); Part 1: Protocol specification33.080Digitalno omrežje z integriranimi storitvami (ISDN)Integrated Services Digital Network (ISDN)ICS:Ta slovenski standard je istoveten z:EN 301 484-1 Version 1.1.1SIST EN 301 484-1 V1.1.1:2005en01-januar-2005SIST EN 301 484-1 V1.1.1:2005SLOVENSKI
STANDARD
ETSIEN301484-1V1.1.1(2000-04)EuropeanStandard(Telecommunicationsseries)IntegratedServicesDigitalNetwork(ISDN);LineHunting(LH)supplementaryservice;DigitalSubscriberSignallingSystemNo.one(DSS1);Part1:ProtocolspecificationSIST EN 301 484-1 V1.1.1:2005

ETSIETSIEN301484-1V1.1.1(2000-04)2ReferenceDEN/SPAN-05171-1KeywordsISDN,DSS1,supplementaryservice,LH,protocolImportantnoticeThisETSIdeliverablemaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshallbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.Usersofthisdocumentshouldbeawarethatthedocumentmaybesubjecttorevisionorchangeofstatus.InformationonthecurrentstatusofthisandotherETSIdocumentsisavailableathttp://www.etsi.org/tb/status/CopyrightNotificationNopartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2000.Allrightsreserved.ETSIPostaladdressF-06921SophiaAntipolisCedex-FRANCEOfficeaddress650RoutedesLucioles-SophiaAntipolisValbonne-FRANCETel.:[phone]Fax:[phone]SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/[e-mail]ETSIdeliverablecanbedownloadedfromhttp://www.etsi.orgIfyoufinderrorsinthepresentdocument,sendyourcommentto:[e-mail] EN 301 484-1 V1.1.1:2005

ETSIETSIEN301484-1V1.1.1(2000-04)3ContentsIntellectualPropertyRights.4Foreword.41Scope.62References.63Definitions.74Abbreviations.85Description.86OperationalRequirements.96.1ProvisionandWithdrawal.96.2Requirementsontheoriginatingnetworkside.106.3Requirementsonthedestinationnetworkside.107Codingrequirements.107.1CodingoftheFacilityinformationelementcomponents.108StateDefinitions.129SignallingProceduresatthecoincidentSandTreferencepoints.129.1Activation,deactivationandinterrogation.129.1.1TemporaryHuntGroupwithdrawal.129.1.1.1Normaloperation.129.1.1.2Exceptionalprocedures.139.1.2CancellationofTemporaryHuntGroupwithdrawal.139.1.2.1Normaloperation.139.1.2.2Exceptionalprocedures.149.1.3Interrogation.149.1.3.1NormalOperation.149.1.3.2Exceptionalprocedures.159.2InvocationandOperation.159.2.1Normaloperation.159.2.2Exceptionalprocedures.159.3Notificationtouserofwithdrawalofanaccessfromahuntgroup.1610ProceduresforinterworkingwithprivateISDNs.1611Interactionswithothernetworks.1612Interactionwithothersupplementaryservices.1613Parametervalues(timers).1614Dynamicdescription(SDLdiagrams).16AnnexA(informative):Signallingflows.17History.19SIST EN 301 484-1 V1.1.1:2005

ETSIETSIEN301484-1V1.1.1(2000-04)4IntellectualPropertyRightsIPRsessentialorpotentiallyessentialtothepresentdocumentmayhavebeendeclaredtoETSI.TheinformationpertainingtotheseessentialIPRs,ifany,ispubliclyavailableforETSImembersandnon-members,andcanbefoundinSR000314:"IntellectualPropertyRights(IPRs);Essential,orpotentiallyEssential,IPRsnotifiedtoETSIinrespectofETSIstandards",whichisavailablefromtheETSISecretariat.LatestupdatesareavailableontheETSIWebserver(http://www.etsi.org/ipr).PursuanttotheETSIIPRPolicy,noinvestigation,includingIPRsearches,hasbeencarriedoutbyETSI.NoguaranteecanbegivenastotheexistenceofotherIPRsnotreferencedinSR000314(ortheupdatesontheETSIWebserver)whichare,ormaybe,ormaybecome,essentialtothepresentdocument.ForewordThisEuropeanStandard(Telecommunicationsseries)hasbeenproducedbyETSITechnicalCommitteeServicesandProtocolsforAdvancedNetworks(SPAN).Thepresentdocumentispart1ofamulti-partENcoveringtheIntegratedServicesDigitalNetwork(ISDN);LineHunting(LH)supplementaryservice;DigitalSubscriberSignallingSystemNo.one(DSS1),asidentifiedbelow:Part1:"Protocolspecification";Part2:"ProtocolImplementationConformanceStatement(PICS)proformaspecification";Part3:"TestSuiteStructureandTestPurposes(TSS&TP)specificationsfortheuser";Part4:"AbstractTestSuite(ATS)andpartialProtocolImplementationeXtraInformationforTesting(PIXIT)proformaspecificationfortheuser";Part5:"TestSuiteStructureandTestPurposes(TSS&TP)specificationforthenetwork";Part6:"AbstractTestSuite(ATS)andpartialProtocolImplementationeXtraInformationforTesting(PIXIT)proformaspecificationforthenetwork".InaccordancewithCCITTRecommendationI.130[7],thefollowingthreelevelstructureisusedtodescribethesupplementarytelecommunicationservicesasprovidedbyEuropeanpublictelecommunicationsoperatorsunderthepan-EuropeanISDN:-stage1:isanoverallservicedescription,fromtheuser'sstandpoint;-stage2:identifiesthefunctionalcapabilitiesandinformationflowsneededtosupporttheservicedescribedinstage1;and-stage3:definesthesignallingsystemprotocolsandswitchingfunctionsneededtoimplementtheservicedescribedinstage1.Thepresentdocumentdetailsthestage3aspects(signallingsystemprotocolsandswitchingfunctions)neededtosupporttheLineHuntingsupplementaryservice.Thestage1aspectsaredetailedindraftEN301479[1].Thestage2aspectsoftheLineHuntingsupplementaryservicehavenotbeenspecified.SIST EN 301 484-1 V1.1.1:2005

ETSIETSIEN301484-1V1.1.1(2000-04)5NationaltranspositiondatesDateofadoptionofthisEN:21April2000DateoflatestannouncementofthisEN(doa):31July2000DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):31January2001DateofwithdrawalofanyconflictingNationalStandard(dow):31January2001SIST EN 301 484-1 V1.1.1:2005

ETSIETSIEN301484-1V1.1.1(2000-04)61ScopeThepresentdocumentspecifiesthestagethreeoftheLineHunting(LH)supplementaryserviceforthepan-EuropeanIntegratedServicesDigitalNetwork(ISDN)asprovidedbytheEuropeanpublictelecommunicationsoperatorsattheTreferencepointorcoincidentSandTreferencepoint(asdefinedinITU-TRecommendationI.411[13])bymeansoftheDigitalSubscriberSystemNo.one(DSS1).Stagethreeidentifiestheprotocolproceduresandswitchingfunctionsneededtosupportatelecommunicationsservice(seeCCITTRecommendationI.130[7]).ThepresentdocumentdoesnotspecifytheadditionalprotocolrequirementswheretheserviceisprovidedtotheuserviaatelecommunicationsnetworkthatisnotanISDN.TheLHsupplementaryserviceenablescallstoasingleISDNnumbertobeofferedtoafreeaccessinagroupofaccessestowhichterminalsareconnected.Theprinciplesfortheselectionofafreechannelwithinanaccessareanetworkprovidermatteraspartofthebasiccallproceduresandsoareoutsidethescopeofthepresentdocument.TheLHserviceisapplicabletoallcircuit-switchedtelecommunicationserviceswiththeexceptionofservicesrequiringtheuseofmorethanoneB-channel.FurtherpartsofEN301484specifythemethodoftestingrequiredtoidentifyconformancetothepresentdocument.2ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.• Anon-specificreferencetoanETSshallalsobetakentorefertolaterversionspublishedasanENwiththesamenumber.[1]ETSIEN301479:"IntegratedServicesDigitalNetwork(ISDN);LineHunting(LH)supplementaryservice;ServiceDescription".[2]ETSIEN300195-1:"IntegratedServicesDigitalNetwork(ISDN);Supplementaryserviceinteractions;DigitalSubscriberSignallingSystemNo.one(DSS1)protocol;Part1:Protocolspecification".[3]ETSIEN300196-1:"IntegratedServicesDigitalNetwork(ISDN);Genericfunctionalprotocolforthesupportofsupplementaryservices;DigitalSubscriberSignallingSystemNo.one(DSS1)protocol;Part1:Protocolspecification".[4]ETSIEN300403-1:"IntegratedServicesDigitalNetwork(ISDN);DigitalSubscriberSignallingSystemNo.one(DSS1)protocol;Signallingnetworklayerforcircuit-modebasiccallcontrol;Part1:Protocolspecification[ITU-TRecommendationQ.931(1993),modified]".[5]ITU-TRecommendationI.112:"VocabularyoftermsforISDNs".[6]ITU-TRecommendationI.210:"PrinciplesoftelecommunicationservicessupportedbyanISDNandthemeanstodescribethem".[7]CCITTRecommendationI.130:"MethodforthecharacterizationoftelecommunicationservicessupportedbyanISDNandnetworkcapabilitiesofanISDN".SIST EN 301 484-1 V1.1.1:2005

ETSIETSIEN301484-1V1.1.1(2000-04)7[8]ETSIEN300089:"IntegratedServicesDigitalNetwork(ISDN);CallingLineIdentificationPresentation(CLIP)supplementaryservice;Servicedescription".[9]ITU-TRecommendationZ.100:"CCITTSpecificationanddescriptionlanguage(SDL)".[10]ITU-TRecommendationE.164:"Theinternationalpublictelecommunicationnumberingplan".[11]ITU-TRecommendationX.680:"Informationtechnology-AbstractSyntaxNotationOne(ASN.1):Specificationofbasicnotation".[12]ITU-TRecommendationX.880:"Informationtechnology-RemoteOperations:Concepts,modelandnotation".[13]ITU-TRecommendationI.411:"ISDNuser-networkinterfaces-Referenceconfigurations".[14]ITU-TRecommendationI.221:"Commonspecificcharacteristicsofservices".3DefinitionsForthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply:Access:generaltermusedinthepresentdocument,denotingbasicaccessesandasanetworkprovideroption,primaryrateaccessesBasicaccess:seeITU-TRecommendationI.112[5],subclause2.4,definition425Basiccallprocedures:proceduresbywhichacall(asaninstanceofabasictelecommunicationsservice)isestablishedandterminatedCyclichunting:selectionofafreeaccessalwaysstartsatthenextaccessaftertheoneusedlast,andfollowsafixedorder.Whenthelastaccessinthegroupisreached,thesearchcontinuesfromthebeginningofthegroupuntilallaccessesinthegrouphavebeensearched,orafreeaccessisfoundDefaultnumber:definedfortheCLIPserviceinEN300089[8]NOTE:Inordertoprovideconsistencyfromacustomerperspectivethesamedefaultnumbermaybeassociatedwithalltheaccessesthatgotoauserinstallation.InthissituationthedefaultnumberisaHuntGroupNumberandtheHuntGroupitrelatestocontainsalltheaccessesthatgotoauserinstallation.Freeaccess:accesstowhichthecallcanbeofferedwithoutexceedingthenumberofusedB-channelsspecifiedforthisaccessHuntgroup:numberofaccessesoverwhichtheLHsupplementaryserviceappliesfortheassignedISDNnumber.AhuntgroupmayconsistofasingleaccessHuntgroupnumber:ISDNnumber,towhichtheLHsupplementaryserviceisallocatedandtowhichISDNbasicservicesandsupplementaryservicesrelatingtothehuntgroupareallocatedHuntgroupwithdrawal:requestbyaaccessofthehuntgroupinordertotemporarilypreventthisaccessfromreceivingcallstothehuntgroup(existingcallsarenotaffected)Individualnumber:(inthecontextofthepresentdocument)ISDNnumberwhichisnotahuntgroupnumber,butwhichcanbeassociatedwithanaccessthatbelongstoahuntgroupinordertoidentifyoneormoreterminalsconnectedtotheaccessIntegratedServicesDigitalNetwork(ISDN):seeITU-TRecommendationI.112[5],subclause2.3,definition308ISDNnumber:numberconformingtothenumberingplanandstructurespecifiedinITU-TRecommendationE.164[10]Network:DSS1protocolentityatthenetworksideoftheuser-networkinterfaceNetworkdetermineduserbusy:seeITU-TRecommendationI.221[14],subclause2.1.4SIST EN 301 484-1 V1.1.1:2005

ETSIETSIEN301484-1V1.1.1(2000-04)8Primaryrateaccess:seeITU-TRecommendationI.112[5],subclause2.4,definition426Sequentialhunting:selectionofafreeaccessalwaysstartswiththesameaccessandthenfollowsafixedorderuntilallaccessesinthehuntgrouphavebeensearchedorafreeaccessisfoundServeduser:usertowhomtheLHserviceisprovidedService;telecommunicationsservice:seeITU-TRecommendationI.112[5],subclause2.2,definition201Supplementaryservice:seeITU-TRecommendationI.210[6],subclause2.4User:DSS1protocolentityattheusersideoftheuser-networkinterfacewhenacoincidentSandTreferencepointappliesUserdetermineduserbusy:seeITU-TRecommendationI.221[14],subclause2.1.44AbbreviationsForthepurposeofthepresentdocument,thefollowingabbreviationsapply:HGHuntGroupISDNIntegratedServicesDigitalNetworkLHLineHuntingLHGLineHuntGroup5DescriptionTheLHsupplementaryserviceisintendedforuseonaccessestowhichterminalsareconnectedattheS/Treferencepoint.TheLHsupplementaryserviceenablescallstoanISDNnumber(i.e.thehuntgroupnumber)tobeofferedtoafreeaccessinahuntgroup.Thehuntgroupcancomprisebasicaccesses,primaryrateaccesses(asanetworkoption),oramixtureofthesetypesofaccesses.TheLHsupplementaryserviceappliestoaccesseswithinahuntgroupthatareconnectedtothesameexchange.AsanetworkoptiontheLHsupplementaryservicecanbeusedtocreateamulti-nodalservicethatallowslinehuntingacrossaccessesonmultipleexchanges.Thespecificationofthemulti-nodalserviceisoutsidethescopeofthepresentdocument,howeverannexAofEN301479[1]considerssomeoftheimplicationsofthisservice.Callsmadetoanindividualnumber(seenote1)maybeofferedonthecorrespondingaccesswithoutbeingsubjecttohuntingprocedures(channelhuntingmaybeperformedwithintheaccessitself).NOTE1:Theindividualaccessesthataremembersofthehuntgroupcanalsohaveindividualnumbers(e.g.,withthemultiplesubscribernumbersupplementaryservice)allocated.Itistheuser'sresponsibilitytoensurecompatibilityoftheequipmentconnectedtoanaccessinahu
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