Robert Elliot Kahn (born December 23, 1938) is an American electrical engineer who, along with Vint Cerf, first proposed the Transmission Control Protocol (TCP) and the Internet Protocol (IP), the fundamental communication protocols at the heart of the Internet.
In 2004, Kahn won the Turing Award with Vint Cerf for their work on TCP/IP.
Background information
Kahn was born in New York to parents Beatrice Pauline (née Tashker) and Lawrence Kahn in an Ashkenazi Jewish family. Through his father, he is related to futurist Herman Kahn. After receiving a B.E.E. degree in electrical engineering from the City College of New York in 1960, Kahn went on to Princeton University where he earned a M.A. in 1962 and Ph.D. in 1964, both in electrical engineering. At Princeton, he was advised by Bede Liu and completed a doctoral dissertation titled "Some problems in the sampling and modulation of signals." He first worked at Bolt Beranek and Newman Inc., then in 1972 joined the Information Processing Techniques Office (IPTO) within DARPA. In the fall of 1972, he demonstrated the ARPANET by connecting 20 different computers at the International Computer Communication Conference, "the watershed event that made people suddenly realize that packet switching was a real technology." He then helped develop the TCP/IP protocols for connecting diverse computer networks. After he became director of IPTO, he started the United States government's billion dollar Strategic Computing Initiative, the largest computer research and development program ever undertaken by the U.S. federal government.
After thirteen years with DARPA, he left to found the Corporation for National Research Initiatives (CNRI) in 1986, and remains its chairman, CEO and president.
The Internet
While working on the SATNET satellite packet network project, he came up with the initial ideas for what later became the Transmission Control Protocol (TCP), which was intended as a replacement for an earlier network protocol, NCP, used in the ARPANET. TCP played a major role in forming the basis of open-architecture networking, which would allow computers and networks all over the world to communicate with each other, regardless of what hardware or software the computers on each network used. To reach this goal, TCP was designed to have the following features:
Small sub-sections of the whole network would be able to talk to each other through a specialized computer that only forwarded packets (first called a gateway, and now called a router). No portion of the network would be the single point of failure, or would be able to control the whole network. Each piece of information sent through the network would be given a sequence number, to ensure that they were dealt with in the right order at the destination computer, and to detect the loss of any of them. A computer which sent information to another computer would know that it was successfully received when the destination computer sent back a special packet, called an acknowledgement (ACK), for that particular piece of information. If information sent from one computer to another was lost, the information would be retransmitted, after the loss was detected by a timeout, which would recognize that the expected acknowledgement had not been received. Each piece of information sent through the network would be accompanied by a checksum, calculated by the original sender, and checked by the ultimate receiver, to ensure that it was not damaged in any way en route.
Vint Cerf joined him on the project in the spring of 1973, and together they completed an early version of TCP. Later, the protocol was separated into two separate layers: host-to-host communication would be handled by TCP, with Internet Protocol (IP) handling internetwork communication. The two together are usually referred to as TCP/IP, and form part of the basis for the modern Internet.
In 1992 he co-founded with Vint Cerf the Internet Society, to provide leadership in Internet related standards, education, and policy.
Awards
In 1981, Bob Kahn was elevated to the grade of IEEE fellow for original work in packet switching mobile radio telecommunications technology.
He was elected as a member to the National Academy of Engineering in 1987 for research contributions in computer networks and packet switching, and for creative management contributions to research efforts in computers and communications.