Schulzrinne has developed new computer languages that will improve the quality of Internet multimedia information. The languages, known as multimedia protocols and control protocols, will bring highly specialized programming and other interactive services, such as distance learning, to a variety of audiences.

  Most Internet communications now consist of written messages and low-quality multimedia, but improved network protocols will soon allow computer users to view an enormous variety of high-quality voice and video.

  "The beauty of this approach is that the same network can efficiently distribute specialized content to millions of users as well as to small groups that are widely dispersed," Schulzrinne says. "For example, I use the Internet to listen on occasion to a German radio station, not available on shortwave, and watch German TV news. The Internet is the only cost-effective way for me, an expatriate German, to hear and view these programs."

  Within a few years, with more network bandwidth, the digital Internet will offer programming as sharp as HDTV with far more variety. Without limits on the number of channels, people anywhere on the globe will be able to search for programming on the Internet and then click on a title to view their choice, live or later.

Real-Time Transport Protocol

  Schulzrinne's RTP provides a computer sending a multimedia transmission with a way to deliver information on how the transmission should be reconstituted at the delivery point.

  RTP also allows computers receiving a multimedia broadcast to relay details on transmission quality back to the sender, allowing that computer to take appropriate corrective measures. The software can report on the quality of service received by any viewer or group of viewers. The protocol has been endorsed by two standardization bodies, the Internet Engineering Task Force and the International Telecommunications Union.

  The new protocol can be used to set up teleconferences, make telephone or videophone calls or request concerts, movies or other multimedia content, all on the Internet. Schulzrinne is also developing distance learning applications in which each remote computer is miked and has its own videocam, enabling students at any location to participate in live, interactive classes.

  With audiences of several millions, Internet traffic control becomes a major quality issue, since a large surge of traffic could overwhelm parts of the network and interrupt service.

  Schulzrinne has analyzed the problem and developed a number of remedies, essentially assuring that the scale of service delivery keeps pace with the number of users.

Session Initiation Protocol

   Schulzrinne envisions a day when the Internet will replace traditional telephone networks, and his Session Initiation Protocol (SIP) offers standard telephone features, including call forwarding, support for automatic call distribution and call transfer. Such a protocol would provide a gateway between phone networks and multimedia computing, allowing a person with Internet telephony to place a call to any telephone on the traditional phone network.

  Within the Internet, SIP could signal voice, video or any other multimedia communication, allowing, for example, interactive videophones. Full implementation of such an Internet-based system would replace both traditional PBXs and telephone switches with SIP gateways.

Real-Time Stream Control Protocol

  Currently, real-time Internet broadcasters use their own simple multimedia protocol. In collaboration with RealNetworks and Netscape Communications Corp., Schulzrinne is designing a control protocol for services such as audio or video on demand. His Real-Time Stream Control Protocol (RTSP) allows users to record multimedia off the Internet and can integrate multimedia content into teleconferences initiated by the SIP gateway. The protocols are under consideration by an industry standards group. The research has been supported by AT&T, Lucent Technologies, IBM, Microsoft, RealNetworks and Reuters.

  For more information, see Schulzrinne's web site at http://www.cs.columbia.edu/~hgs/research/IRT.