NOTE: This charter is accurate as of the 29th IETF Meeting in Seattle. It may now be out-of-date. (Consider this a "snapshot" of the working group from that meeting.) Up-to-date charters for all active working groups can be found elsewhere in this Web server.

Multiparty Multimedia Session Control (MMUSIC) Charter


Mailing List Information

Description of Working Group

The demand for Internet multimedia teleconferencing has arrived, yet an infrastructure to support this demand is barely in place. Multimedia session control, defined as the management and coordination of multiple sessions and their multiple users in multiple media (e.g., audio, video), is one component of the infrastructure. The Multiparty Multimedia Session Control Working Group is chartered to design and specify a protocol to perform these functions.

The protocol will provide negotiation for session membership, underlying communication topology and media configuration. In particular, the protocol will support a user initiating a multimedia multiparty session with other users (``calling'' other users) over the Internet by allowing a teleconferencing application on one workstation to explicitly rendezvous with teleconferencing applications running on remote workstations. Defining a standard protocol will enable session-level interoperability between different teleconferencing implementations.

The focus of the working group is to design a session agreement protocol that supports tightly-controlled conferences in addition to the loosely-controlled ones currently carried on the MBone. Loosely-controlled sessions have little to no interaction among members, thus limiting their ability to provide security or coordination of session attributes (e.g., quality-of-service options for time-critical media, floor control for media flows). Users may learn of loosely-controlled sessions using the ``sd'' utility or other out of band mechanisms (e.g., e-mail, WWW). However, there is clearly also a need for more tightly-controlled sessions that provide mechanisms for directly contacting other users to initiate a conference and for negotiating conference parameters such as membership, media encodings and encryption keys. In addition, these sessions should support renegotiation during a session, for example, to add or delete members or change the media encoding.

The main goal of the working group will be to specify the session control protocol for use within teleconferencing software over the Internet. The working group will focus on the aspects of the session control problem that are well understood, while keeping an eye on evolving research issues. Toward this end, the working group has made an inventory of existing conferencing systems and their session control protocols. The working group will document the requirements of the existing prototypes as a basis for the protocol development. The working group will iteratively refine the protocol based on implementation and operational experience.

Furthermore, the working group will coordinate with other efforts related to multimedia conferencing, such as directory services for cataloging users and conferences, the RTP and RTCP protocols developed by the Audio/Video Transport Working Group, resource reservation and management at the network level, and schemes for multicast address allocation.

Goals and Milestones

May 1993
Hold an on-line working group meeting to discuss the conference control framework, the relevant terminology, a functional taxonomy and how different conversational styles place requirements on session protocols.
Jun 1993
Submit the Conference Session Control Protocol to the IESG for consideration as an Experimental Protocol.
Aug 1993
Post an Internet-Draft describing the Session Control Requirements.
Nov 1993
Post an Internet-Draft of the Session Control Protocol.
Mar 1994
Submit a revised Internet-Draft based on implementation experience.