Internet Architecture Board


Interim Approval for Internet Telephone Numbering System (ENUM) Provisioning, 24 May 2002

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Countries wishing to implement ENUM system may now do so
System offers promise of standardized international Voice and Video on IP services

Washington, DC – May 24, 2002 – The International Telecommunication Union (ITU) and the Internet Architecture Board (IAB) announce interim approval for a single domain for ENUM, a technology that builds a bridge between the public switched telephone network and the Internet.

Voice on IP networks today operate by translating telephone numbers to IP addresses and placing an H.323 or SIP call to the device. The interchange format and translation record has not heretofore been standardized, limiting the possibility of deployment of multi-corporate and international Voice on IP services. Under the ENUM proposal, E.164 numbers can be represented as Internet Domain Names,providing a scalable and standard way to translate the numbers, and opening the way to such services. ITU has begun approving delegations for the purposes of trials. “The lack of an interoperable standard way to turn a telephone number into an IP Address has been one factor limiting the deployment of Voice on IP services internationally”, said Leslie Daigle, Chair of the Internet Architecture Board.

If desk-mounted computers or servers are given telephone numbers as well as mnemonic names, this system further enables common telephone handsets to place Voice or Video on IP calls to such computers. This is a significant step towards integrating Internet-based services with the global telephone network, and the current agreements between IAB and ITU will allow trials to take place.

Patrik Faltstrom, member of the Internet Engineering Steering Group (IESG), said that “the integration of the desktop telephone and computer allows corporations to simplify their internal networks.” Roy Blane, Chair of ITU-T’s Study Group 2, concurred, saying that “In the long term this protocol may facilitate many new internet services. In the short term, countries wishing to trial the system can begin work on developing it.”

This interim approval is made possible due to cooperation between ITU, IAB and the Internet Engineering Task Force (IETF). As outlined in the ENUM specification document, RFC 2916, sub-domains from a single domain will be delegated after acceptance by the registries according to the existing assignment of country codes in the telephone address space.

Information on how the ENUM registration requests will be processed can be found at

About ISOC

The Internet Society
<> is a non-profit, non-governmental, open membership organization whose worldwide individual and organization members make up a veritable “who’s who” of the Internet industry. It provides leadership in technical and operational standards, policy issues, and education. ISOC is the organizational home of the International Engineering Task Force, the Internet Architecture Board, the Internet Engineering Steering Group, and the Internet Research Task Force – the standards setting and research arms of the Internet community.

About the IETF

The Internet Engineering Task Force is an international community of network designers, operators,vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. The definition of the ENUM protocol, as proposed by the IETF can be found at The IETF is an organized activity of the Internet Society.

About ITU

The International Telecommunication Union (ITU) is a global organization where the public and private sectors cooperate for the development of telecommunications and the harmonization of national telecommunications policies. Study Group 2 of the ITU Telecommunication Standardization Sector (ITU-T), where work on ENUM is being carried out, is the Lead Study Group on Service definition,Numbering, Routing and Global Mobility and is responsible for the operational aspects of service provision, networks and performance. More information on the ENUM protocol, and the issues related to it, can be found at


Patrik Fältström
Leslie Daigle
Scott Bradner
Roy Blane
Richard Hill
Lynn St.Amour

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