Contact:	Bob Nelson						For immediate release
		(212) 854-5573					June 5, 1997
		rjn2@columbia.edu



Internet Protocol Sharpens Voice, Video
___________________

Columbia Scientist Sees Wide Use of Computers 
to Make Phone Calls; Anticipates Huge Variety of Programming, Including
College Football


	Newcomers to the Internet often complain that multimedia
information is scattered, difficult to find and of poor quality.  That 
situation is about to change, says Henning Schulzrinne, assistant
professor of computer science and electrical engineering at Columbia, who
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 to a variety
 of audiences.  Versions of Microsoft NetMeeting and Netscape Conference now
 being shipped already include his Real-Time Transport Protocol (RTP) for
 sending real-time multimedia over the Internet.  He is one of a handful of 
scientists who are addressing the entire range of potential Internet applications,
 including interactive multimedia and Internet telephony. 
	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 distributed," Professor Schulzrinne said.  "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."
	Why subscribe to Internet media when cable television now provides varied
programming?  In a few years, with more network bandwidth, the digital 
Internet will offer programming as sharp as HDTV with far more variety.  "Over-
the-air or cable broadcast HDTV will always have a limited number of channels,
 equivalent to the current number of regular TV channels, so it's only useful for
 mass entertainment," Professor Schulzrinne said.  Without any limits on the 
number of channels, Columbia alumni anywhere on the globe, for example, could 
view the winning football team.  Access will be more direct, too; users will search
 for programming and then click on a title to view it, live or at their convenience.
	Existing Internet protocols break up information into small packets that
 may take different routes to their destination, a feature that assures the 
information will be promptly delivered but can degrade the quality of live
 multimedia broadcasts, since packets arriving out of sequence create flickering 
in voice or video.  Professor Schulzrinne's Real-Time Transport Protocol (RTP) 
provides sufficient information to the delivery point to allow that system to 
recreate the stream of multimedia data originated by the sender.  RTP also 
provides a mechanism for letting the receivers tell the sender how well audio and
 video are being received, so that the sender can take appropriate corrective 
measures, such as switching to a coding that is more resilient to packet loss, or
 increasing the transmission quality when there is spare bandwidth.  The protocol
 has already 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.  RTP also incorporates signaling protocols, feedback controls that 
report on quality of service and network traffic.  Unlike a traditional telephone
 conference call, RTP allows the conferencing software to indicate who is talking,
 and also shows how many people are connected to the same teleconference or 
watching the same program, information that national television networks now 
must infer statistically from Nielsen and other rating systems.  The software can
 also measure the quality of service received by any viewer or group of viewers.
	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.  Professor 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.  "These new features will likely be 
integrated into the next release of the standard, due this summer," he said.
	He 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, so that someone with Internet telephony could 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 simple SIP gateways.  "I can't speculate on
 when the Internet will completely replace the phone system, but my goal is to
 make this technically feasible and desirable," Professor Schulzrinne said.
	Currently, real-time Internet broadcasters such as VDO or RealAudio use
 their own simple multimedia protocol.  In collaboration with Progressive 
Networks (RealAudio) and Netscape Communications Corp., Professor
 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 currently under
 consideration by an industry standards group.
	The research has been supported by AT&T, Lucent Technologies, IBM,
 Microsoft, Progressive Networks and Reuters.
	More information about Professor Schulzrinne's RTP protocols is available
 at http://www.cs.columbia.edu/~hgs/research/IRT.html.

This document is available at http://www.columbia.edu/cu/pr/.  Working press
 may receive science and technology press releases via e-mail by sending a message to rjn2@columbia.edu.

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