Centralized Conferencing (xcon)

In addition to this official charter maintained by the IETF Secretariat, there is additional information about this working group on the Web at:

       Additional XCON Web Page

Last Modified: 2009-04-15

Additional information is available at tools.ietf.org/wg/xcon

Chair(s):

  • Alan Johnston <alan@sipstation.com>

  • Adam Roach <adam@nostrum.com>

    Real-time Applications and Infrastructure Area Director(s):

  • Robert Sparks <rjsparks@nostrum.com>
  • Cullen Jennings <fluffy@cisco.com>

    Real-time Applications and Infrastructure Area Advisor:

  • Robert Sparks <rjsparks@nostrum.com>

    Mailing Lists:

    General Discussion: xcon@ietf.org
    To Subscribe: https://www1.ietf.org/mailman/listinfo/xcon
    Archive: http://www.ietf.org/mail-archive/web/xcon/index.html

    Description of Working Group:

    The focus of this working group is to develop a standardized suite of
    protocols for tightly-coupled multimedia conferences, where strong
    security and authorization requirements are integral to the solution.
    Tightly-coupled conferences have a central point of control and
    authorization (known as a focus) so they can enforce specific media and
    membership relationships, and provide an accurate roster of
    participants. The media mixing or combining function of a
    tightly-coupled conference need not be performed centrally, however.

    The scope of this effort is intentionally more narrow than previous
    attempts to standardize conferencing (e.g. centralized control), and is
    intended to enable interoperability in a commercial environment which
    already has a number of non-standard implementations using some of the
    protocols.

    Privacy, security, and authorization mechanisms are integral to the
    solution generated by the working group. This includes allowing
    participants to be invisible to all but the conference owner, or to be
    visible but participate anonymously with respect to some or all of
    the other participants.

    Authorization rules allow for participants and non-participants
    to have roles (ex: speaker, moderator, owner), and to be otherwise
    authorized to perform membership and media manipulation for or on
    behalf of other participants. In order to preserve these properties,
    the protocols used will require implementation of channel security
    and authentication services.

    Due to the centralized architecture of the WG, XCON's mechanisms will
    place requirements on the signaling protocol used between the focus
    and
    the participants. At a high level, the signaling protocol must be able
    to establish, tear down, modify, and perform call control operations on
    multimedia streams, including voice, video, and instant messaging, in
    both a centralized and distributed mixing architecture. SIP will be
    the
    reference session signaling protocol used for examples; however, none
    of
    the XCON solutions themselves will be signaling protocols, nor will
    XCON
    extend existing signaling protocols. Other signaling protocols than
    SIP
    may be used between the focus and participants, including non-IETF
    protocols, but the requirements and possible extensions needed for
    other
    signaling protocols to utilize the full functionality of the XCON
    architecture is outside the scope of XCON.

    The deliverables for the group will be:
    - A mechanism for membership and authorization control
    - A mechanism to manipulate and describe media "mixing" or "topology"
      for multiple media types (audio, video, text)
    - A mechanism for notification of conference related events/changes
    (for
      example a floor change)
    - A basic floor control protocol

    The initial set of protocols will be developed for use in unicast media
    conferences. The working group will perform a second round of work to
    enhance the set of protocols as necessary for use with multicast media
    after their initial publication.

    The following items are specifically out-of-scope:
    - Voting
    - Fully distributed conferences
    - Loosely-coupled conferences (no central point of control)
    - Far-end device control
    - Protocol used between the conference controller and the mixer(s)
    - Capabilities negotiation of the mixer(s)
    - Master-slave cascaded conferences

    The working group will coordinate closely with the SIPPING and
    MMUSIC working groups. In addition the working group will cooperate
    with other groups as needed, including SIP, MSEC, AVT, and the W3C
    SMIL working groups. In addition, the working group will consider
    a number of existing drafts as input to the working group.

    Goals and Milestones:

    Done  Submit Requirements for Basic Floor Control for publication as Informational
    Done  Submit Conferencing Scenarios document for publication as Informational
    Done  Submit Basic Floor Control Protocol for publication as PS
    Done  Submit Framework for publication as PS
    Done  Submit Event Notification Package for publication as PS
    Aug 2009  Submit Conference Data Model for publication as PS
    Aug 2009  Submit Conference Control Protocol for publication as PS
    Dec 2009  Submit Policy Model for publication as PS
    Dec 2009  Set milestones for any IM-related conferencing work
    Apr 2010  Submit Conferencing Call Flows Document for publication as Informational

    Internet-Drafts:

    Conference Information Data Model for Centralized Conferencing (XCON) (186872 bytes)
    Conference Event Package Data Format Extension for Centralized Conferencing (XCON) (28972 bytes)
    Centralized Conferencing Manipulation Protocol (159830 bytes)

    Request For Comments:

    Requirements for Floor Control Protocol (RFC 4376) (30021 bytes)
    Conferencing Scenarios (RFC 4597) (38428 bytes)
    The Binary Floor Control Protocol (BFCP) (RFC 4582) (154497 bytes)
    Connection Establishment in the Binary Floor Control Protocol (BFCP) (RFC 5018) (20244 bytes)
    A Framework for Centralized Conferencing (RFC 5239) (146927 bytes)
    IETF Secretariat - Please send questions, comments, and/or suggestions to ietf-web@ietf.org.

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