Mark Foster Internet Draft                                              Tom McGarry Document: <draft-ietf-enum-e164-gstn-np-05.txt>                James Yu                                                           NeuStar, Inc. Category: Informational                                   June 24, 2002                 Number Portability in the GSTN: An Overview   Status of this Memo     This document is an Internet-Draft and is in full conformance with    all provisions of Section 10 of RFC2026 [RFC].      Internet-Drafts are working documents of the Internet Engineering    Task Force (IETF), its areas, and its working groups. Note that    other groups may also distribute working documents as Internet-   Drafts. Internet-Drafts are draft documents valid for a maximum of    six months and may be updated, replaced, or obsoleted by other    documents at any time. It is inappropriate to use Internet- Drafts    as reference material or to cite them other than as "work in    progress."         The list of current Internet-Drafts can be accessed at    http://www.ietf.org/ietf/1id-abstracts.txt.         The list of Internet-Draft Shadow Directories can be accessed at    http://www.ietf.org/shadow.html.         Copyright Notice        Copyright (C) The Internet Society (2002).  All rights reserved.            Abstract        This document provides an overview of E.164 telephone number    portability (NP) in the Global Switched Telephone Network (GSTN).       NP is a regulatory imperative seeking to liberalize local telephony    service competition, by enabling end-users to retain telephone    numbers while changing service providers.  NP changes the    fundamental nature of a dialed E.164 number from a hierarchical    physical routing address to a virtual address, thereby requiring the    transparent translation of the later to the former.  In addition,    there are various regulatory constraints that establish relevant    parameters for NP implementation, most of which are not network    technology specific.  Consequently, the implementation of NP    behavior consistent with applicable regulatory constraints, as well    as the need for interoperation with the existing GSTN NP    implementations, are relevant topics for numerous areas of IP    telephony work-in-progress at IETF.   Foster,McGarry,Yu         Expired on December 23, 2002        [Page 1] Number Portability in the GSTN: An Overview               June 24, 2002        Table of Contents         1.  Introduction ...............................................  2     2.  Abbreviations and Acronyms .................................  4     3.  Types of Number Portability ................................  5     4.  Service Provider Number Portability Schemes ................  7        4.1   All Call Query (ACQ) ..................................  7        4.2   Query on Release (QoR) ................................  8        4.3   Call Dropback .........................................  9        4.4   Onward Routing (OR) ...................................  9        4.5   Comparisons of the Four Schemes ....................... 10     5.  Database Queries in the NP Environment ..................... 11        5.1   U.S. and Canada ....................................... 12        5.2   Europe ................................................ 13     6.  Call Routing in the NP Environment ......................... 14        6.1   U.S. and Canada ....................................... 14        6.2   Europe ................................................ 15     7.  NP Implementations for Geographic E.164 Numbers ............ 17     8.  Number Conservation Method Enabled By NP ................... 20        8.1   Block Pooling ......................................... 20        8.2   ITN Pooling ........................................... 21     9.  Potential Implications ..................................... 21    10.  Security Considerations .................................... 24    11.  IANA Considerations ........................................ 24    12.  Normative References ....................................... 24    13.  Informative References ..................................... 25    14.  Acknowledgement ............................................ 25    15.  Authors