Requirements for Multiple Address of Record (AOR) Reachability Information in the Session Initiation Protocol (SIP)

This document states requirements for a standardized SIP registration mechanism for multiple addresses of record (AORs), the mechanism being suitable for deployment by SIP service providers on a large scale in support of small to medium sized Private Branch Exchanges (PBXs). The requirements are for a solution that can, as a minimum, support AORs based on E.164 numbers. This document is not an Internet Standards Track specification; it is published for informational purposes.