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