As Service Providers introduce and expand IP-based service offerings, there is increasing interest in identifying the opportunities for the industry to facilitate IP routing of Voice over IP (VoIP) traffic using E.164 addresses. The ATIS/SIP Forum IP-Network-to-Network (NNI) Task Force took on the initiative to develop a Technical Document and is publishing a report to describe the candidate proposals for circulation and comment.

Recognizing that IP traffic exchange is developing as an overlay to existing Time-Division Multiplexing (TDM) interconnection and will be implemented by different service providers with varying timelines, the purpose of this draft report is to:
1. Provide an overview of in-use and proposed architectures with the provisioning processes and calls flows to facilitate the exchange of VoIP traffic associated with IP-based services using E.164 addresses.
2.Present comparative characteristics that may be useful in understanding the approaches.
3. Consider how such in-use and proposed solution(s) may be adopted and/or coexist, and evolve for transition to a future integrated registry envisioned at the FCC Numbering Testbed Workshop.