Global ENUM Implementation

1. Global ENUM Implementation DTI ENUM Workshop5 June 2001 London, UK Robert Shaw <robert.shaw@itu.int> ITU Internet Strategy and Policy Advisor International Telecommunication Union

2. Caveats • Complex topic • Focused on E.164 policy and infrastructure issues • ENUM services are primarily national issues • with some exceptions (e.g., +800) • Work in progress

3. What is E.164? • ITU-T Recommendation E.164: “The international public telecommunication numbering plan” • Tied to treaty obligations (specific roles and obligations defined for ITU Member States and TSB Director) • Defines number structure and functionality for four principal categories of numbers: • Geographic Areas • Global Services • Networks • Groups of Countries (“GoCs”)

4. Examples of E.164 Resources • Geographic areas • ITU Member States, including integrated numbering plan involving more than one (e.g., +1) • Global Services • e.g., Universal International Freephone Numbers (+800) • Networks • Global Mobile Systems (+881 + 1 digit IC) • Shared code for Networks (+ 882 + 2 digit IC) • Groups of Countries • e.g., ETNS

5. Related to E.164 • ITU-T Recommendation E.164.1: Criteria and procedures for the reservation, assignment and reclamation of E.164 country codes and associated Identification Codes (ICs); • ITU-T Recommendation E.164.2: E.164 numbering resources for trials (to be published); • Determined Recommendation E.164.3: Principles, criteria and procedures for the assignment and reclamation of E.164 country codes and associated identification codes for Groups of Countries (determined at January 2001 meeting of SG2); • ITU-T Recommendation E.190: Principles and responsibilities for the management, assignment and reclamation of E-series international numbering resources; • E.195: ITU-T International numbering resource administration

6. Issues of Convergence • Problems of addressing calls that pass from one network service to another: • Now widely possible to originate calls from IP address-based networks to other networks • But uncommon to terminate calls from other networks to IP address-based networks • To access a subscriber on an IP address-based network, some sort of global addressing scheme across PSTN and IP address-based networks needed • ENUM may be the “glue” solution…

7. What is ENUM? • IETF protocol defined in RFC 2916 • E.164 number used to look up Uniform Resource Identifier (URI) • Web addresses most commonly known URI • Allows using E.164 number in context of combined PSTN & IP services (email, fax, SIP address, coordinates, IP telephony routing, other?) • Could be important integrator of PSTN, Internet, and other IP-based networks

8. What is ENUM? • Protocol uses what are called Naming Authority Pointer (“NAPTR”) DNS resource records as defined in RFC 2915 • Identifies the available methods or services for contacting a specific Internet node identified through an E.164 number as well as their order of priority/preference: • e.g., redirect calls, “follow-me” services, contact by email, look up public key, ???

9. How would E.164 numbers be mapped into the DNS? • Reverse map digits in an E.164 number into separate DNS “names” • Concatenate with “ENUM root zone” (e.g., foo.tld) • For example: • +33 1 40 20 51 51 = 1.5.1.5.0.2.0.4.1.3.3.foo.tld • What foo.tld is and how exactly it is administrated is under discussion

10. Roles and Responsibilities • In telecommunication numbering, regulatory tradition with strong government involvement (e.g., number portability, anti-slamming) • In the Internet, management of naming and addressing has been left to “industry self-regulation” • Among early movers, assumption appears to be that national numbering/regulatory authorities will be involved in assisting in ENUM deployment for their portion of E.164 resources in respective countries

11. Roles and Responsibilities • Most ENUM service and administrative decisions are national issues under purview of ITU Member States, since most E.164 resources are utilized nationally • ITU to ensure that Member States havespecifically authorized inclusion of geographic country code in the DNS • In integrated numbering plan, each ITU Member State within plan may administer their portion of E.164 resources mapped into DNS as they see fit

12. Basic Technical Requirements • Scaleable, robust and secure DNS infrastructure must be provided at all hierarchical levels of the DNS. • Hierarchical registry operations and name servers that coordinate delegations of E.164 numbering resources will need to be deployed at the international, national and sub-national levels • Important for geopolitical, sovereignty, security and other pragmatic reasons

13. DNS Infrastructure • To support geographically dispersed national resources, the ENUM root zone foo.tld require DNS backbone dispersed around the world • Main ENUM name servers (e.g., root zone & CC) should be capable of sustaining loads probably comparable to that carried by current root name servers • Geopolitical and technical constraints need to be balanced (e.g., limitations of 15-20 name servers)

14. DNS Infrastructure • Following principles of E.164, important to have “country-neutral”, internationally acceptable solution; • History of DNS suggests that transparency needed as to clear legal and policy framework, roles, responsibilities and relationships; • General view that desirable to have one public ENUM name space (one root) • Global infrastructure choices needs to reviewed in this context (e164.arpa, .arpa name server deployment)

15. Current .arpa Name Server Deployment

16. ITU Responsibilities • Operate a registry function or coordinate a registry function for top level of E.164 • Outsource or coordinate the outsourcing of ENUM name servers corresponding to top level of E.164 numbering plan • Define and implement administrative procedures that coordinate delegations of E.164 numbering resources into these name servers

17. Remaining Issues • Requirement for review of E.164 legal and policy framework when reflected in DNS? • Without safeguards, ITU Member States will find their E.164 resources are provisioned or shadowed in “alternative” name spaces outside of their control • Like DNS “country codes”, could E.164 resources be “marketed” outside their intended geographic/regulatory framework (e.g., .tv, .md, .ws, .bz)?

18. Remaining Issues • Privacy • Hardening the ENUM zone data against data mining but hard to stop ENUM name servers being harvested for resources bound to an E.164 number • Could drive non-DNS based ENUM solution (e.g., LDAP-based) • Financial operations issues • Major ENUM name servers probably cost US$ 150,000-500,000 per year to operate • ITU Member States & Sector Members need to consider how global infrastructure costs will be shared

19. ITU Current Activities • Ongoing review of policy and technical issues with assistance of Nominum, Inc. • Preparation of in-depth technical and policy requirements discussion paper • ITU-T SG 2 preparing supplement on issues that need to be addressed by national and international authorities • ITU-T SG 2 Meeting in Sept 2001 • Further discussion with IETF on roles and responsibilities • Plan for testbed countries?

20. Thank You • References and resources • http://www.itu.int/infocom/enum/