Robert Elliot Kahn, (born December 23,
1938) invented the TCP protocol, and along with Vinton G. Cerf created
the IP protocol, the technologies used to transmit information on the
After receiving a B.E.E. from the City College of New York in 1960,
Dr. Kahn earned M.A. and Ph.D. degrees from Princeton University in
1962 and 1964 respectively.
In 1972 he moved to ARPA (now known as DARPA), and in October of that
year, he demonstrated the ARPANET by connecting 40 different computers
at the International Computer Communication Conference, publicizing
the network to the general public for the first time. After he became
Director of DARPA's Information Processing Techniques Office (IPTO),
he started the United States government's billion dollar Strategic
Computing Program, the largest computer research and development
program ever undertaken by the U.S. federal government.
While working on a 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. While working on this, he
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
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, it was
separated into two separate layers, with the more basic functions
being moved to the Internet Protocol (IP). The two together are
usually referred together as TCP/IP, and are the basis for the modern
After thirteen years with DARPA, he left to found the Corporation for
National Research Initiatives (CNRI) in 1986, and as of 2006 is the
Chairman, CEO and President. CNRI is a nonprofit organization which is
intended to provide leadership and funding for research and
development of the National Information Infrastructure.
He was awarded the SIGCOMM Award in 1993 for "for visionary technical
contributions and leadership in the development of information systems
technology", and shared the 2004 Turing Award with Vint Cerf, for
"pioneering work on internetworking, including .. the Internet's basic
communications protocols .. and for inspired leadership in
He is a recipient of the AFIPS Harry Goode Memorial Award, the Marconi
Award, the ACM SIGCOMM Award, the President's Award from ACM, the IEEE
Koji Kobayashi Computer and Communications Award, the IEEE Alexander
Graham Bell Medal, the IEEE Third Millennium Medal, the ACM Software
Systems Award, the Computerworld/Smithsonian Award, the ASIS Special
Award and the Public Service Award from the Computing Research Board.
He has twice received the Secretary of Defense Civilian Service Award.
He is a recipient of the 1997 National Medal of Technology, the 2001
Charles Stark Draper Prize from the National Academy of Engineering,
the 2002 Prince of Asturias Award, and the 2004 A. M. Turing Award
from the Association for Computing Machinery. Dr. Kahn received the
2003 Digital ID World award for the Digital Object Architecture as a
significant contribution (technology, policy or social) to the digital
identity industry. In 2005 he was awarded the Townsend Harris Medal
from the Alumni Association of the City College of New York, the
Presidential Medal of Freedom, and the C & C Prize in Tokyo, Japan. He
was inducted into the National Inventors Hall of Fame in May 2006. He
was awarded the 2008 Japan Prize for his work in "Information
Communication Theory and Technology" (together with Vinton Cerf).
In 2001 he was inducted as a Fellow of the Association for Computing
Dr. Kahn has received honorary degrees from Princeton University,
University of Pavia, ETH Zurich, University of Maryland, George Mason
University, the University of Central Florida and the University of
Pisa, and an honorary fellowship from University College, London.