PD 6626:2000

0 PREFACE
      0.1 Title
      0.2 Normative Information
      0.3 Contents
      0.4 History
      0.5 Issue Control
      0.6 References
      0.7 Glossary of terms
             0.7.1 Definitions
             0.7.2 Abbreviations
      0.8 Scope
1 GENERAL GNP CONSIDERATIONS
      1.1 Requirements
             1.1.1 General Requirements
             1.1.2 Requirements of Networks
             1.1.3 Requirements of Originating Networks
             1.1.4 Requirements of Donor Networks
             1.1.5 Requirements of Transit Networks
             1.1.6 Requirements of Recipient Networks
      1.2 GNP Functions
             1.2.1 Call Trap Function
             1.2.2 Routeing Number Determination Function
             1.2.3 Routeing Number Addition Function
2 SOLUTIONS FOR GEOGRAPHIC NUMBER PORTABILITY
      2.1 Overview of GNP Solutions
      2.2 Short Term: Onward Routeing
      2.3 Medium Term: Call Dropback
             2.3.1 Advantages of Call Dropback
             2.3.2 Disadvantages of Call Dropback
      2.4 Medium Term: Query on Release
             2.4.1 Advantages of Query on Release
             2.4.2 Disadvantages of Query on Release
      2.5 Long Term: All Call Query
             2.5.1 Advantages of All Call Query
             2.5.2 Disadvantages of All Call Query
3 INTERWORKING OF NUMBER PORTABILITY SOLUTIONS
      3.1 Starting Point - The Onward Routeing Solution
      3.2 Introduction of Dropback Number Portability
             Solution with Onward Routeing
      3.3 Introduction of Query on Release (QoR) Number
             Portability Solution with Onward Routeing
      3.4 Introduction of All Call Query (ACQ) Number
             Portability Solution with Onward Routeing
4 NUMBERING FORMAT
      4.1 Background
      4.2 Requirements
      4.3 Routeing Number Format
             4.3.1 C7 signalling using Interconnect User
                      Part (IUP)
             4.3.2 Other signalling systems
      4.4 Administration

The function whereby a customer may transfer provision of his telecommunications service to another licensed operator, without change of E.164 number (telephone number) is called GNP, as defined in the Number Portability Functional Specification issued from time to time by OFTEL. Addressed in this document, GNP is restricted to fixed telecommunications services with geographical significant E.164 numbers. All types of numbers, e.g including Centrex and DDI number ranges are encompassed by this Service Description. However, GNP is specified as NUMBER and NOT Service or Feature Portability. The call control functionality necessary to support GNP is presented. Maintenance and Operation aspects of GNP are described in the End-to-End Process Manual. PNO-ISC defines support for GNP in various interconnect signalling systems