Mark Foster Internet Draft Tom McGarry Document: 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
