Global ENUM Implementation DTI ENUM Workshop 5 June 2001 London, UK Robert Shaw <robert.shaw@itu.int> ITU Internet Strategy and Policy Advisor International Telecommunication Union

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

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”) ITU-T Recommendation E.164, “The international public telecommunication numbering plan”, defines the number structure and functionality for four principal categories of numbers used for international public telecommunication – namely geographic areas, Global Services, Networks, and Groups of Countries (“GoCs”). For each of the categories, Recommendation E.164 details the components of the numbering structure and the digit analysis required to successfully route calls. Other specific Recommendation E.164-based applications (e.g., Universal International Freephone Numbers), which differ in usage, are defined in separate ITU-T Recommendations. As the assignment and allocation of specific numbering resources are subject to ongoing operationally dictated amendment, the ITU does not publish them as part of ITU-T Recommendation E.164 but rather as periodic supplements[2] announced in Annexes to the ITU Operational Bulletin.[3] As required by WTSA Resolution 20, every international Recommendation E.164 code allocation or reclamation is transparent to all ITU Member States, Sector Members and operators. [2] For example, see http://www.itu.int/ITU-T/bulletin/codes.html. [3] http://www.itu.int/ITU-T/bulletin/.

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

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

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…

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

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, ???

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

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

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 have specifically 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

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

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)

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)

Current .arpa Name Server Deployment

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

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)?

Remaining Issues Privacy Financial operations issues 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

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?

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