High-Level Requirements for Tightly Coupled SIP Conferencing
RFC 4245

 
Document Type RFC - Informational (November 2005; No errata)
Last updated 2013-03-02
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IESG IESG state RFC 4245 (Informational)
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Responsible AD Allison Mankin
Send notices to gonzalo.camarillo@ericsson.com, dean.willis@softarmor.com, rohan@ekabal.com
Network Working Group                                           O. Levin
Request for Comments: 4245                         Microsoft Corporation
Category: Informational                                          R. Even
                                                                 Polycom
                                                           November 2005

      High-Level Requirements for Tightly Coupled SIP Conferencing

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document examines a wide range of conferencing requirements for
   tightly coupled SIP conferences.  Separate documents will map the
   requirements to existing protocol primitives, define new protocol
   extensions, and introduce new protocols as needed.  Together, these
   documents will provide a guide for building interoperable SIP
   conferencing applications.

Table of Contents

   1. Introduction ....................................................2
   2. An Overview .....................................................2
   3. High-Level Requirements .........................................3
      3.1. Discovery Phase ............................................3
      3.2. Conference Creation ........................................4
      3.3. Conference Termination .....................................4
      3.4. Participants' Manipulations ................................4
         3.4.1. Participation of a Conference-Unaware User Agent ......5
         3.4.2. Dial-Out Scenarios ....................................5
         3.4.3. Dial-In Scenarios .....................................5
         3.4.4. Third-Party Invitation to a Conference ................6
         3.4.5. Participants' Removal .................................6
         3.4.6. Participants' Privacy .................................6
      3.5. Conference State Information ...............................7
         3.5.1. Description ...........................................7
         3.5.2. Dissemination of Changes ..............................7
         3.5.3. On-demand Information Dissemination ...................8
      3.6. Focus Role Migration .......................................8

Levin & Even                 Informational                      [Page 1]
RFC 4245               Conferencing Requirements           November 2005

      3.7. Side-bar Conferences .......................................8
      3.8. Cascading of Conferences ...................................9
      3.9. SIMPLE and SIP Conferencing Coordination ...................9
   4. Security Considerations ........................................10
   5. Contributors ...................................................10
   6. References .....................................................10
      6.1. Normative References ......................................10

1.  Introduction

   This document examines a wide range of conferencing requirements for
   tightly coupled SIP (RFC 3261 [2]) conferencing.

   The requirements are grouped by subjects in various areas allowing
   solutions to progress in parallel.

   Separate documents will map the requirements to existing protocol
   primitives, define new protocol extensions, and introduce new
   protocols as needed.

   Together, these documents will provide a guide for building
   interoperable SIP conferencing applications.

   The terms "MAY", "SHOULD", and "MUST" are to be interpreted as
   described in RFC 2119 [1].

2.  An Overview

   A SIP conference is an association of SIP user agents (i.e.,
   conference participants) with a central point (i.e., a conference
   focus), where the focus has direct peer-wise relationships with the
   participants by maintaining a separate SIP dialog with each.

   The focus is a SIP user agent that has abilities to host SIP
   conferences including their creation, maintenance, and manipulation
   using SIP call control means and potentially other non-SIP means.

   In this tightly coupled model, the SIP conference graph is always a
   star.  The conference focus maintains the correlation among
   conference's dialogs internally.

   The conference focus can be implemented either by a participant or by
   a separate application server.

   In the first case, a focus is typically capable of hosting a simple
   ad hoc conference only.  We envision that such basic conference can
   be established using SIP call control primitives only.

Levin & Even                 Informational                      [Page 2]
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