Videoconferencing Debuts on the Internet

February 28, 1995

By Jeffery Kahn,

BERKELEY -- In March 1992, a new venue quietly debuted on the Internet -- one in which people worldwide could meet in a common electronic window and not only see and talk to one another, but work on a shared "whiteboard." This conferencing network -- called the Multicast Backbone, or MBone -- has the potential to launch a new era in scientific collaboration.

"Among scientists," predicts Stewart Loken, "MBone conferencing will become as routine as e-mail. And, it will happen much sooner than you think."

Loken, a pioneer in the use of videoconferencing, oversees LBL researchers who have played a prominent role in creating the MBone. Having invented most of the tools used during an MBone conference, LBL researchers most recently helped create new protocols that soon should make the MBone accessible to anybody with an Internet-linked workstation.

Today, the MBone is the fastest growing component of the Internet. Since its inception, MBone conferencing has grown exponentially with traffic doubling about every eight months. Right now, more than 10,000 people in 30 countries are using it for collaborative work.

Despite its explosive growth, the MBone has been difficult to access with most of its usage by computer scientists and engineers doing network research. This is because the routers that direct traffic around the Internet are unable to deal with multicast (MBone) addressing. Consequently, local and regional networks have had to be jury-rigged to patch individuals to an MBone session. New router software is coming onto the market that will automate the MBone. Anyone on the Internet will be able to conference with everyone else on the Internet.

LBL's Van Jacobson is one of the three principal creators of MBone. The others are Steve Deering, of Xerox Corp.'s Palo Alto Research Center, and Steve Casner of the University of Southern California. Deering and Casner developed the multicasting protocols that made the virtual network possible, and Jacobson created many of the tools that make it valuable.

In multicasting, rather than send information to a single location, the network distributes it from senders to every receiver who has signed up for the session. Because MBone usually includes live video, which means huge volumes of traffic, efficiency was a prerequisite to prevent congestion and collapse of the Internet. The software underlying MBone dynamically finds the shortest, most efficient paths, sending a single copy of a video conference onto the network, and replicating it only where there is a split in the path leading to individual participants.

MBone was first used to simulcast the March 1992 Internet Engineering Task Force conference. Since then, it has provided around-the-clock coverage of space shuttle flights, an opportunity for doctors in England and Sweden to observe and question a surgeon in San Francisco performing a complex liver operation, and a place for Ph.D. candidates to defend their dissertations to committee members.

"The tools are so easy to use that anybody can announce a session and be their own producer," Jacobson says. "Somebody actually sent out to the universe live pictures of their pet iguana climbing a tree."

MBone offers a number of advantages over traditional teleconferencing, which joins together only those rooms specifically wired for videoconferencing. MBone joins all those who have a workstation with audio/video capabilities and a high-speed Internet connection. This ability to connect many more individual offices has resulted in moves by both the Department of Energy and NASA to replace teleconferencing with MBone meetings.

Jacobson's research group at LBL includes Steve McCanne and Sally Floyd. Jacobson and McCanne designed the whiteboard, which Jacobson calls an "infinite piece of paper." It allows participants in an MBone session to write, type, and draw on a shared drawing window. It even has a memory, so that those using it can flip pages, scrolling back to earlier versions of the contents, or import other drawings and text.

Jacobson also developed the session directory, a conference coordination tool that provides a menu of what is currently available or upcoming on MBone. The Session Directory allows the user to join a session, or to announce and advertise an upcoming session.

The tool pack developed by Jacobson's group also includes VIC (Video Conferencing) and VAT (Visual Audio Tool). These make it possible for all parties to both talk and listen. It also makes possible the transmission of a video stream to an unlimited number of participants.

Most recently, Jacobson was part of the team that developed the Protocol Independent Multicast software upon which the next generation of routers will be based. Thanks to Jacobson, Deering, and researchers from the University of Southern California and Cisco Systems, multicasting will now be a basic feature of routers. With this change, the labor-intensive patching required to hookup to an MBone conference will be eliminated. This means that the MBone now will become an integral and invisible part of the Internet.

Says Loken, "I believe that 1995 will be to MBone what 1994 was to the World Wide Web. Almost unknown right now, Internet videoconferencing is about to become commonplace."

LBL is a national laboratory that conducts unclassified scientific research for the U.S. Department of Energy. It is located in Berkeley, California, and is managed by the University of California.