1. 12/18/2000 ENUM Administration Penn Pfautz AT&T 732-420-4962 ppfautz@att.com

2. 12/18/2000 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?

3. 12/18/2000 e164.arpa (RIPE-NCC) 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 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!". $ORIGIN e164.arpa. 1 IN NS nsnanp_enum.com 4.6 IN NS sweden_enum.com. Tier 1 – Registry- defined by ITU member state Tier 2 – Service Registrar ENUM Hierarchy sip.att.com Tier 3 – Application Service Provider

4. 12/18/2000 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

5. 12/18/2000 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

6. 12/18/2000 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)

7. 12/18/2000 Reference Model I (General) T1E T2E End User TSP ASP A B C F G E D New T2E H Legend ASP Application Service Provider TIE Tier 1 Entity (Registry) T2E Tier 2 Entity (Registrar) TSP Telephony Service Provider ** 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.

8. 12/18/2000 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

9. 12/18/2000 Reference Model II (T2E=TSP) T1E T2E/TSP End User Legend ASP Application Service Provider TIE Tier 1 Entity (Registry) T2E Tier 2 Entity (Registrar) TSP Telephony Service Provider ASP A’ C’ New T2E/TSP E’ B’ D’ ** 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.

10. 12/18/2000 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

11. 12/18/2000 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

12. 12/18/2000 Major Issues Entity to be Service Registrar Authentication of rights to number –Number assignment –User identity Disconnect notification –Who informs Registry? Telephony service specific records

13. 12/18/2000 References Patrik Faltstrom, “E.164 Number and DNS” RFC 2916. draft-pfautz-na-enum-01.txt draft-pfautz-yu-enum-adm-00.txt draft-ranalli-peek-walter-enum-t1roles- 00.txt