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ENUM Administration. Penn Pfautz AT&T 732-420-4962 ppfautz@att.com. ENUM Administration. Mixes domain registration and telephone number administration Rights to ENUM domain tied to corresponding number assignment in the PSTN
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ENUM Administration Penn Pfautz AT&T 732-420-4962 ppfautz@att.com
ENUM Administration • Mixes domain registration and telephone number administration • Rights to ENUM domain tied to corresponding number assignment in the PSTN • Rights to number in ENUM lost when service on number is disconnected • Generally, telephone service provider is only party that knows about number assignments & disconnects • Design issue for industry & regulators: How to balance need for TSP involvement with burden on TSP and a competitive environment?
ENUM Hierarchy Tier 0 - e164.arpa (RIPE-NCC) $ORIGIN e164.arpa. 1 IN NS nsnanp_enum.com 4.6 IN NS sweden_enum.com . ... Tier 1 – Registry- defined by ITU member state nsnanp_enum.com (1.e164.arpa) 4.6.e164.arpa Sweden $ORIGIN 3.7.9.1.e164.arpa. 7.8.7.6.6.3.2 IN NS e164.att.net. 8.8.7.6.6.3.2 IN NS joes-enum.com Tier 2 – Service Registrar e164.att.net $ORIGIN 7.8.7.6.6.3.2.3.7.9.1.e164.arpa. IN NAPTR 10 10 "u" "sip+E2U" "!^.*$!sip:sdlind@sip.att.com!" . IN NAPTR 102 10 "u" "mailto+E2U" "!^.*$!mailto:sdlind@att.com!" . IN NAPTR 102 10 "u" "tel+E2U" "!^.*$!tel:+19732366787!" . Tier 3 – Application Service Provider sip.att.com
e164.arpa • .arpa TLD since infrastructure • RIPE NCC will host • Essentially populated with identities of name servers for country codes • ITU indicates to RIPE authority for each country code
Tier 1 (Registry) • Entries point to Service Registrar for a number • Provider(s) determined by national authorities • NANP-wide or per NANP nation? • Because of number portability, Tier 1 name server must point to Service Registrar on an individual number basis; numbers can’t simply be delegated to the carrier to which their Central Office code or thousands block was initially assigned
Tier 2 (Service Registrar) • Hosts NAPTR (service) records for a telephone number • All records for a given number must be in one name server • Major issue is who can be Service Registrar • Two “strawman” models presented to IETF • Any properly accredited domain name registrar (model I) • Telephone service provider (model II)
Reference Model I (General) Legend ASP Application Service Provider TIE Tier 1 Entity (Registry) T2E Tier 2 Entity (Registrar) TSP Telephony Service Provider T1E New T2E A H ** End User can be the end user itself or an agent authorized to represent the end user. ** TSP can offer application services also. The “TSP” entity performs functions specific to the TSP. B C T2E End User F G E D TSP ASP
Reference Model I – Pros & Cons Pros: • EU determines T2E, EU has more control • EU can be T2E (e.g., universities and enterprises) for his/her own TN(s) • Enable competitive T2E service offering Cons: • More complicated interactions among involved entities • More efforts at T2E to manage the NAPTR RRs
Reference Model II (T2E=TSP) T1E Legend ASP Application Service Provider TIE Tier 1 Entity (Registry) T2E Tier 2 Entity (Registrar) TSP Telephony Service Provider A’ B’ T2E/TSP End User ** End User can be the end user itself or an agent authorized to represent the end user. ** TSP can offer application services also. The “TSP” entity performs functions specific to the TSP. E’ C’ D’ ASP New T2E/TSP
Reference Model II – Pros & Cons Pros: • Fewer interfaces to deal with • Easier to verify EU’s identity and ownership of the TN • More incentives for TSPs to get involved in enum process (e.g., verify EU’s ownership of a TN and inform T1E about TN service disconnect) Cons: • Only TSPs can be T2E, non-competitive if there is only one TSP in a serving market • Non-TSPs cannot be T2E • (except through delegation from TSP) • EUs cannot be T2E for their own TNs • EUs cannot get enum service if none of TSPs in the serving market offers enum service
Telephony Service Specific Records • Are there services for which the TSP should have right to put records in ENUM? • How can TSP control records in Tier 2 of end user choice? • How might these records be distinguished? • Alternative is to treat TSP like any other application service provider • Ability of TSP to populate ENUM for customer will facilitate penetration
Major Issues • Will the US populate its numbering resources in e164.arpa? • Will the countries of the NANP take an integrated or independent approach to ENUM implementation? • What entity or entities will provide Tier 1 functionality? • What entities may be Service Registrars? • How will authentication of rights to numbers be assured • How will disconnect notification be handled? • Will there be special telephony service specific records?