Presentation on theme: "ENUM Administration Issues"— Presentation transcript:
1 ENUM Administration Issues Some numbering perspectivesITU-T ENUM WorkshopGeneva17 January 2001Tony HolmesBTSteve LindAT&T
2 Agenda WP1/2 Liaison to IETF/ISOC Some typical call flows ENUM DNS structure and HierarchyENUM Considerations and issuesA glossary of terms used can be found at the end of this slide pack
3 The Aim of this sessionTo help raise awareness and assist administrations in understanding what needs to happen to make ENUM workTo consider the administration requirements of ENUMTo identify issues…..not only those that need to be tackled by the ITU but also by Member States and other parties
4 WP1/2 Liaison to IETF/ISOC Results of DNS Administrative discussions and Contributions - October 2000 ITU-T WP1/2 Meeting - Berlin.Understandings regarding the method for administering and maintaining the E.164-based resource data in the DNS.Administration = provision and update of E.164 numerical values, of domain “e164.arpa”, in the DNS.Example of “e164.arpa” domain name:e164.arpaAdministrative Zones defined:e164.arpa = Domain Zone3.3 = Country Code Zone= National ZoneNote: Here ‘Zone’ refers to a segment of the domain name
5 WP1/2 Liaison to IETF/ISOC Agreements regarding the administration of ZonesDomain Zone is outside the scope of the ITUCountry Code ZoneITU provides assignment data to the DNS AdministratorITU Member States authorize/deny the ITU to notify the registrar of E164.arpa to include their Country CodeNo data entry for “spare” or test codesNational ZoneNational Matter - determined by each Member StateShared Network Codes - each entity determinesGroups of Countries - the administrative entity for the Group determines, in consultation with participating Member States
6 WP1/2 Liaison to IETF/ISOC Other AgreementsOnce data input is authorized, each Member State/Administrative Entity is responsible for update and accuracy of data.Data not authorized for input will not be entered in the DNS.All Administrative Entities (including the DNS Administrator) will adhere to the tenets of pertinent ITU Recommendations e.g. E.190, E.164 etc.WP1/2 will provide guidance to assist the Member States and Administrative Entities in the performance of their responsibilities - the purpose of this meeting.
7 Typical call flows PSTN - IP GatewayIPNetworkDNSDNS look up returnsNAPTR record with46DNS returns SIP server IP address5Gateway looks up host for7SIP server routes call to user12( ENUM functionality)formats urle164.arpa3
8 Typical call flows IP - PSTN 3DNS returns record as urltel:PSTNGatewayIPNetworkDNSLocationserver12Client formats url4SIP Client initiatesINVITE to server using tel url6LS returns IP address of Gateway5SIP sever looks up gateway address from LS7Call routed to GatewayIP address8Gateway completes call to PSTN
10 ENUM Considerations - 1 Inserting numbers in the DNS Tier 1 Registry Registries will be identified by each participating Member StateEntries will point to the Service Registrar for a numberITU & IETF position states:ITU has responsibility to provide assignment information.Geographic Country Codes will only be included in the DNS when authorised by the Member State responsible for that codeISSUEAn agreed process needs to be developed e.g. between appropriate authorities (participating Member States, potentially ITU-T) and Tier 1 Registries
11 ENUM Considerations - 2 Inserting numbers in the DNS Tier 1 Registry ITU & IETF position states:Each administration is responsible for ensuring DNS administrators (Registries) are aware of appropriate changesISSUESMaintaining integrity of E.164Building ENUM integrityNot all countries have the same regulation or rules of administration BUT all need to address the same issues for ENUMHow should Tier 1 Registries be selected?- it’s a national matterbut there are options…….
12 ENUM Considerations - 3 Inserting numbers in the DNS Tier 1 Registry …could be one or more Tier 1 Registry providers per CC e.g.- integrated number plan could be separated by national authorities- Tier1 Registry(s) could be separated by number ranges within a CC but there can only be one Registry per E.164 numberISSUESHow to determine the most appropriate arrangement?Who runs national Registries?An agreed process needs to be developed between participating Member States and their Tier 1 Registry provider(s)(national matter).
13 ENUM Considerations - 4 Inserting numbers in the DNS Tier 1 Registry ITU & IETF position states:For national zone resources behind the CC shared by Networks the resource assignee is responsible for providing E.164 assignment information to the DNS AdministratorNetwork Code assignees need to be made aware of ENUM rulesITU Recs may require amendment to embrace thisITU & IETF position states:For national zone resources behind the CC shared by Groups of Countries the resource assignee is responsible for providing E.164 assignment information to the DNS AdministratorITU Recs may require amendment/development to embrace this
14 ENUM Considerations - 5 Inserting numbers in the DNS Tier 1 Registry Entries in the Tier 1 Registry point to the Service Registrar for an E164 numbere164.arpaTier 2 ServiceRegistrarISSUEIn some cases with Number Portability, the name server must point to a Service Registrar on an individual E164 number basis, not a number blockThe full implications on all methods of NP and associated processes need to be understood
15 ENUM considerations - 6 Inserting numbers in the DNS Enables the use of an E.164 number allocated to a Service Provider to be used to deliver calls to another Service ProviderISSUESNetwork by-passSome countries are moving to single number administration and payment for numbers, does this raise additional issues?Rights of ownership?- differences across administrations?- Intellectual Property Rights?
16 ENUM considerations - 7 Inserting numbers in the DNS Enables the use of an E.164 number allocated to a Service Provider to be used to deliver calls to another Service ProviderISSUESCustomer perception where an E.164 number that provides access to an ISP, other than the one responsible for the number, experiences differing QoS and cost?Privacy of information/consumer protectionLegal intercept?Regulatory implicationse.g monitoring of QoS etc?
17 ENUM Considerations - 8 Inserting numbers in the DNS Tier 2 Service Registrare164.arpaTier 1 RegistryTier 2 ServiceRegistrarhosts NAPTR records for E.164 numbersAll records for a given number must be in one name serverpoints to Registrypoints to Service Registrar for an E.164 numberISSUEDetermination of who qualifies to be a Service Registrar?Two alternatives under discussionModel 1 - any accredited domain name/service registrarModel 2 - telephone service provider
18 Reference Model I (General) LegendASP Application Service ProviderT1E Tier 1 Entity (Registry)T2E Tier 2 Entity (Registrar)TSP Telephony Service ProviderEU End UserT1ENew T2EAH** End User can be the end user itself oran agent authorized to representthe end user.** TSP can offer application servicesalso. The “TSP” entity performsfunctions specific to the TSP.BCT2EE UFGEDTSPASP
19 ENUM Considerations - 9 Model I Pros & Cons Pros: Reference Model IT1ENew T2EModel I Pros & ConsAHCT2EE UBGFEDTSPASPPros:EU determines T2E, EU has more controlEU can be T2E (e.g., universities and enterprises) for his/her own E.164 number(s)Enable competitive T2E service offeringCons:More complicated interactions among involved entitiesMore efforts at T2E to manage the NAPTR RRs
20 Reference Model II (T2E=TSP) LegendASP Application Service ProviderT1E Tier 1 EntityT2E Tier 2 EntityTSP Telephony Service ProviderEU End UserA’B’T2E/TSPE U** End User can be the end user itself oran agent authorized to representthe end user.** TSP can offer application servicesalso. The “TSP” entity performsfunctions specific to the TSP.E’C’D’New T2E/TSPASP
21 ENUM Considerations - 10 Pros: Fewer interfaces to deal with Reference Model IIPros:Fewer interfaces to deal withEasier to verify End Users’s identity and ownership of the E.164 NumberMore incentives for TSPs to get involved in ENUM process(e.g., verify End User’s ownership of a E.164 Number and inform T1E about E.164 number service disconnect)T1EB’A’T2E/TSPE UE’C’D’New T2E/TSPASPCons:Only TSPs can be T2E, non-competitive if there is only one TSP in a serving marketNon-TSPs cannot be T2EEnd Users cannot be T2E for their own E.164 NumbersEnd Users cannot get ENUM service if none of TSPs in the serving market offers ENUM service
22 ENUM Considerations - 11 Inserting numbers in the DNS Tier 2 Service RegistrarSome Administration issues from the Service Registrar modelsIs one, or a number of different model(s) preferable?Who should be Service Registrars?How can E.164/DNS integrity be safeguarded if responsibility for number insertion in the DNS lies with the customer?How should validation of subscriber identity, data & NAPTR (service records) occur?How can number/name hijacking/fraud be prevented?
23 ENUM Considerations - 12 Inserting numbers in the DNS ISSUES How will number changes/number churn be handled?How will ceased numbers be notified/recovered?Could prepaid mobile numbers be inserted?If so how will ownership be validated ?How will changes/ownership/loss/ theft/cease issues be addressed?Who has these responsibilities?
24 ENUM Considerations - 13 Inserting numbers in the DNS ISSUES Geographic numbers would lose location information, will begin to look more like personal numbersImpact on number plans/number administration?Are additional controls required where numbers are shared?Should/could requirements on carriers/third parties be enforced?Do ENUM procedures and rules apply if E.164 numbers are inserted in other domain name space (e.g .com/other domains) ?