Multimedia Conferencing

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Multimedia Conferencing over the Internet will in the future cover a wide range of events with differing requirements, ranging from small private meetings to broadcasts of workshops and larger events. Our project goal, in proposed work, is to develop a scalable session management architecture and protocol to support the full range of conference sizes and modes as seamlessly as possible. The architecture would incorporate control of intermediate agents for access across firewalls and to gateway to H.320 circuit-switched systems to enable a transition to an Internet-based communication infrastructure.

[IMAGE] It is the capability for multicast transmission in the Internet that enables scaling up to much larger conferences or events than commercial systems can support. We helped create the Multicast Backbone, or MBone, which is an experimental deployment of IP multicasting in the Internet, to support multimedia conferencing and other applications. An FAQ about the MBone is available; it explains how to connect to the MBone and where to pick up the multimedia tools.

Our project has developed a session manager tool, called mmcc, to orchestrate point-to-point or multipoint teleconferences. It allows a caller to explictly invite others to participate in a conference, and alerts them to accept or decline. It automatically spawns underlying audio, video and groupware programs among members of a session, then tears them down at session completion. Mmcc will distribute a session key for confidential sessions. In this preliminary version, the key is sent in the clear, so it is not secure, but future versions will use Kerberos or certificates for secure key distribution.

Mmcc aims to supplement the large open-style sessions supported by the existing version of LBL's session directory tool, sd. It complements the hailing-channel approach of public sessions with a more private session style for smaller conferences. Thus, session advertisement is internal to the group of participating conferees.

The model is that each mmcc is associated with a single user at a particular host and port, and that the program is expected to be left running while a user is logged in to listens for communication from peer mmcc's distributed throughout the Internet. The tool implements distributed coordination among multiple peers, and relies on the initiating user being responsible for session establishment.

The mmcc binary is available for: