CONTENTS

�1���� Scope�������� 1
�2���� References
�3���� Definitions
������� 3.1���� General terms
������� 3.2���� E.164-specific terms
������� 3.3���� ITU-T non-numbering terms
������� 3.4���� DNS-specific terms
������� 3.5���� ENUM-related terms
�4���� Abbreviations
�5���� Background
������� 5.1���� What is ENUM
������� 5.2���� DNS zones and delegation
������� 5.3���� Tiered architecture
������� 5.4���� Overview of ENUM functions and entities
�6���� General administrative issues and options
������� 6.1���� Identification of ENUM Tier 1 Registry or Registries
������� 6.2���� Delegation of names from the ENUM Tier 1 Registry
������� 6.3���� Determination of ENUM Tier 2
Name Server Provider and ENUM Registrars
������� 6.4���� Validation of ENUM requests and records
������� 6.5���� Relationships of administrative structures with ENUM zone structures
������� 6.6���� Additional considerations
�7���� Implications of ENUM for country codes assigned to geographic areas
������� 7.1���� Administration aspects, options and interfaces
������� 7.2���� Review of consequences
����������������� 7.2.1���� Ease of validation of relation between E.164 number and telephony subscriber
����������������� 7.2.2���� Analysis of complexity and effort associated with provisioning
�8���� Summary and conclusion
�9���� Supplement history
Appendix I � Typical PSTN-IP call flows using SIP
Appendix II � Integrated numbering plans