RFC 3245 (rfc3245) - Page 2 of 10

The History and Context of Telephone Number Mapping (ENUM) Operational Decisions: Informational Documents Contributed to ITU-T Study Group 2 (SG2)

RFC 3245   History and Context of ENUM Operational Decisions  March 2002


1. Introduction: ENUM Background Information

   In January 2002, in response to questions from the ITU-T Study Group
   2 (referred to just as "SG2", below), specifically its group working
   on "Questions 1 and 2", and members of the IETF and
   telecommunications communities, Scott Bradner, as Area Director
   responsible for the ENUM work and ISOC Vice President for Standards,
   initiated an effort to produce explanations of the decisions made by
   the IETF about ENUM administration.  The effort to produce and refine
   those documents eventually involved him, Patrik Faltstrom (author of
   RFC 2916), and several members of the IAB.

   The documents have now been contributed to ITU-T, and are being
   published as internal SG2 documents.  This document provides the IETF
   community a copy of the information provided to SG2.  Section 2 below
   contains the same content as COM 2-11-E, section 3 contains the same
   content as COM 2-12-E, and section 4 contains the same content as SG2
   document COM 2-10-E.  The documents being published within SG2 show
   their source as "THE INTERNET SOCIETY ON BEHALF OF THE IETF", which
   is a formality deriving from the fact that ISOC holds an ITU sector
   membership on behalf of the IETF.

2. Why one and only one domain is used in ENUM

2.1. Introduction

   This contribution is one of a series provided by the IETF to ITU-T
   SG2 to provide background information about the IETF's ENUM Working
   Group deliberations and decisions.  This particular contribution
   addresses the IETF's decision that only a single domain could be
   supported in ENUM.

2.2. The need for a single root in the DNS

   In the Domain Name System (DNS), each domain name is globally unique.
   This is a fundamental fact in the DNS system and follows
   mathematically from the structure of that system as well as the
   resource identification requirements of the Internet.  Which DNS
   server is authoritative for a specific domain is defined by
   delegations from the parent domain, and this is repeated recursively
   until the so-called root zone, which is handled by a well-known set
   of DNS servers.  Note that words like "authoritative" and
   "delegation" and their variations are used here in their specific,
   technical, DNS sense and may not have the same meanings they normally
   would in an ITU context.






Klensin                      Informational