The Session Initiation Protocol (SIP) "Join" Header

This document defines a new header for use with SIP multi-party applications and call control. The Join header is used to logically join an existing SIP dialog with a new SIP dialog. This primitive can be used to enable a variety of features, for example: Barge-In, answering-machine-style Message Screening and Call Center Monitoring. Note that definition of these example features is non- normative. [STANDARDS-TRACK]