A Brief Prehistory of Voice over IP parts 1 & 2
Google Tech Talk
August 10 & 11, 2010
Presented by Danny Cohen and Stephen Casner.
This talk explores the development of interactive packet voice beginning in 1974 with experiments over the ARPAnet in the NSC (Network Speech/Secure Communication) program sponsored by ARPA, initiated by Bob Kahn. One highlight will be the showing of a movie made in 1978 to demonstrate a multi-party teleconference over the packet network, including one participant interfaced from a telephone. The talk will be presented in two sessions (two days), with the movie shown at the start of the second session.
Part one covers concepts and lessons from this project:
* A 1971 realtime distributed flight simulation that sparked the idea
* Understanding real-time vs non-real-time communication
* Digital speech and the need to compress it (PCM, DPCM, CVSD, LPC/LPC10)
* Network Voice Protocol (NVP) over the ARPAnet, type0/type3 packets
* The birth of the Internet with TCP * Separating IP from TCP and adding UDP
* Building NVP-II on top of IP
* Adding packet video (DCT based compression)
Part two emphasizes the development of the voice protocols:
* Introducing and showing the teleconferencing movie from 1978
* Advances in equipment and function at the end of NSC in 1982
* Progress stalled, waiting to low-cost vocoding * Development of IP Multicast and the MBone
* Evolution from NVP to RTP, and RTP design philosophy
* Conferencing control protocols
* More recent history of VoIP
Danny Cohen, SunLab at Oracle
Danny led projects that pioneered realtime interactive applications over the ARPAnet and the Internet, such as visual flight simulation, packet-voice (aka Voice over IP) and packet-video.
After teaching at Harvard he joined USC/ISI where he started many network related projects, including Packet-Voice (aka Voice over IP), Packet-Video, Internet Concepts, MOSIS, Digital Library, e-commerce, and ATOMIC which was the forerunner of Myrinet.
Later, Danny co-founded Myricom (with Bob Felderman, Chuck Seitz, and others) which commercialized Myrinet, a high-performance system area network. In 2001 he joined Sun and was working there on very fast communication over very short distances, using optical and electrical signaling. He is perhaps best known for coining the terms "Big Endians" and "Little Endians".
Danny is a member of the National Academy of Engineering (NAE), a fellow of the IEEE, and was a Sun Microsystems Distinguished Engineer until he was sold to Oracle. He was also a bona fide member of the International Flat Earth Society, and an instruments rated commercial pilot for single- and multi-engine planes, land and Sea.
Stephen Casner, Packet Design
Stephen L. Casner received his M.S. in Computer Science from the University of Southern California in 1976. At USC's Information Sciences Institute with Danny Cohen, he designed and implemented protocols and software for some of the earliest experiments with packet voice using the ARPAnet. Later, he was the primary organizer for the establishment of the worldwide Internet Multicast Backbone (MBONE) in its initial experimental phase. In 1995, he took this work to the commercial arena with further development of packet-based audio and video technology for both conferencing and streaming applications at Precept Software, which was acquired by Cisco Systems. He served as chairman of the Audio/Video Transport working group of the Internet Engineering Task Force from its inception in 1992 until 2003. This group has developed the Real-time Transport Protocol (RTP) for packet audio and video as well as other real-time multicast and unicast applications. Currently at Packet Design he is applying some of the same techniques in network performance measurement and routing analysis.