RFC 3482 (rfc3482) - Page 2 of 30


Number Portability in the Global Switched Telephone Network (GSTN): An Overview



Alternative Format: Original Text Document



RFC 3482      Number Portability in the GSTN: An Overview  February 2003


Table of Contents

   1.  Introduction .................................................  2
   2.  Abbreviations and Acronyms ...................................  4
   3.  Types of Number Portability ..................................  6
   4.  Service Provider Number Portability Schemes ..................  7
       4.1   All Call Query (ACQ) ...................................  8
       4.2   Query on Release (QoR) .................................  9
       4.3   Call Dropback .......................................... 10
       4.4   Onward Routing (OR) .................................... 11
       4.5   Comparisons of the Four Schemes ........................ 11
   5.  Database Queries in the NP Environment ....................... 13
       5.1   U.S. and Canada ........................................ 13
       5.2   Europe ................................................. 14
   6.  Call Routing in the NP Environment ........................... 15
       6.1   U.S. and Canada ........................................ 16
       6.2   Europe ................................................. 17
   7.  NP Implementations for Geographic E.164 Numbers .............. 19
   8.  Number Conservation Method Enabled By NP ..................... 22
       8.1   Block Pooling .......................................... 22
       8.2   ITN Pooling ............................................ 23
   9.  Potential Implications ....................................... 23
   10. Security Considerations ...................................... 27
   11. IANA Considerations .......................................... 27
   12. Normative References ......................................... 27
   13. Informative References ....................................... 28
   14. Acknowledgement .............................................. 29
   15. Authors' Addresses ........................................... 29
   16. Full Copyright Statement ..................................... 30

1. Introduction

   This document provides an overview of E.164 telephone number [E164]
   portability in the Global Switched Telephone Network (GSTN).  There
   are considered to be three types of number portability (NP): service
   provider number portability (SPNP), location portability (not to be
   confused with terminal mobility), and service portability.

   SPNP, the focus of the present document, is a regulatory imperative
   in many countries seeking to liberalize telephony service
   competition, especially local service.  Historically, local telephony
   service (as compared to long distance or international service) has
   been regulated as a utility-like form of service.  While a number of
   countries had begun liberalization (e.g., privatization, de-
   regulation, or re-regulation) some years ago, the advent of NP is
   relatively recent (since ~1995).





Foster, et al.               Informational