# Presentation: 722251

## 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?

## ...

- 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

## 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)

**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.**

## 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**

**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.**

## 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

- Entity to be Service Registrar
- Authentication of rights to number
- Number assignment
- User identity
- Disconnect notification
- Who informs Registry?
- Telephony service specific records

## 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