Centralized Conferencing (xcon)
-------------------------------

Charter
Last Modified: 2006-03-24

Current Status: Active Working Group

Chair(s):
    Adam Roach  <[email protected]>
    Alan Johnston  <[email protected]>

Real-time Applications and Infrastructure Area Director(s):
    Jon Peterson  <[email protected]>
    Cullen Jennings  <[email protected]>

Real-time Applications and Infrastructure Area Advisor:
    Cullen Jennings  <[email protected]>

Mailing Lists:
    General Discussion:[email protected]
    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

  Jul 2006       Submit Framework and Data Model for publication as PS

  Oct 2006       Submit Common Conference Information Definition for publication
               as PS

  Nov 2006       Submit Conference Template Definition for publication as PS

  Dec 2006       Submit Conference Control Protocol for publication as PS

  Dec 2006       Submit Event Notification Package for publication as PS

  Dec 2006       Set milestones for any IM-related conferencing work


Internet-Drafts:

Posted Revised         I-D Title   <Filename>
------ ------- --------------------------------------------
May 2005 Jan 2007   <draft-ietf-xcon-framework-07.txt>
               A Framework and Data Model for Centralized Conferencing

Dec 2005 Jan 2007   <draft-ietf-xcon-bfcp-connection-03.txt>
               Connection Establishment in the Binary Floor Control Protocol
               (BFCP)

Apr 2006 Oct 2006   <draft-ietf-xcon-common-data-model-03.txt>
               A Common Conference Information Data Model for Centralized
               Conferencing (XCON)

Request For Comments:

 RFC   Stat Published     Title
------- -- ----------- ------------------------------------
RFC4376 I    Feb 2006    Requirements for Floor Control Protocol

RFC4597 I    Aug 2006    Conferencing Scenarios

RFC4582 PS   Nov 2006    The Binary Floor Control Protocol (BFCP)