1. Concepts and Challenges 2. IETF SPEERMINT: Requirements 3. IETF SPEERMINT: Architecture 4. IETF SPEERMINT: Call Procedures 5. Addressing and Numbering Concepts 6. ENUM Standards and Operation 7. Implementing ENUM 8. ENUM Trials 9. NetNumber TITAN Services 10. The SPIDER Registry 11. VeriSign ENUM Data Access Services 12. Neustar's SIP-IX 13. Telcordia's Service Interconnection Registry 14. Nominum Navitas 15. Digium's DUNDI 16. Voice Peering Fabric ENUM Registry 17. XConnect ENUM Exchange 18. PBX Trunking 19. The SIP-Connect Reference Architecture 20. The SIP-Connect Interface Specification 21. Industry Support for SIP Trunking