SIP Call Control Services

Document Type Expired Internet-Draft (mmusic WG)
Authors Jonathan Rosenberg  , Henning Schulzrinne 
Last updated 1999-06-25
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
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Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document describes a set of extensions to SIP which allow for various call control services. Example services include blind transfer, transfer with consultation, multi-party calls, bridged conferences, and ad-hoc conferencing. The services are supported in a fully distributed manner, so that they can be provided without a central conference server. However, a SIP proxy can act as a conference server to provide these services. For the various services described here, we overview the requirements for the service, and specify the protocol functions needed to support it. We then define a basic set of SIP primitives which can be used to construct these services, and others.


Jonathan Rosenberg (
Henning Schulzrinne (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)