Bob Kahn

Bob Kahn the American engineer and computer scientist (born 1938) who, with Vint Cerf, invented the transmission control protocol and the internet protocol that form the technical foundation of the internet. He originated the open-architecture networking that allowed independent networks to be joined together, and he has since worked on the design of the information infrastructure and on digital object architecture.

Early Life and Education

Robert Elliot Kahn was born on 23 December 1938 in Brooklyn, New York. He showed an early aptitude for mathematics and science, and he studied electrical engineering at the City College of New York, graduating in 1960. He went on to Princeton University, where he earned a master's degree in 1962 and a doctorate in 1964, working on signal processing and communication theory. These studies gave him a deep grounding in the mathematics of information transmission.

After graduating he joined Bell Laboratories, where he worked on theoretical problems in communications and on the design of networks. He then moved to the Massachusetts Institute of Technology as an assistant professor of electrical engineering, teaching and pursuing research on network theory. His academic work prepared him for the practical problems of computer networking that he would soon confront.

The ARPANET and Open-Architecture Networking

In 1972 Kahn joined the Advanced Research Projects Agency of the United States Department of Defense, where he became the programme manager responsible for the ARPANET. He organized the first public demonstration of the network at an international conference in 1972, an event that helped to spread awareness of packet switching. He also recognized that the growing number of separate networks needed a way to interconnect without imposing a common internal design on each of them.

This insight led to the concept of open-architecture networking, in which the specification would define only how networks and hosts communicate with one another, leaving each network free to use its own internal technology. The idea was radical because it did not require any network to change its internal operation, only to adopt a common set of protocols at the boundary. It made the interconnection of diverse and independently operated networks practical.

TCP/IP and Network Protocols

Working with Vint Cerf, Kahn developed the protocols that realized open-architecture networking. The transmission control protocol was designed to provide reliable, ordered delivery of data across an unreliable network, while the internet protocol handled addressing and the routing of packets between networks. Together they allowed dissimilar networks to appear to their users as one seamless system, and they were described in a paper published in 1974.

Kahn directed the large-scale demonstration of the protocols and the transition of the ARPANET to them in the early 1980s. He understood that the technical work had to be matched by institutional arrangements, and he helped to create the processes by which the protocols were refined and standardized. The robustness and simplicity of the design are the reasons the same basic protocols still carry the traffic of the internet today.

Later Work and the Information Infrastructure

After leaving the defence agency in 1985, Kahn founded the Corporation for National Research Initiatives, a not-for-profit organization that supports research on the technology and infrastructure of the information age. There he led work on the design of a national information infrastructure and on the standards and policies needed to make it work. He also became a leading figure in the study of digital libraries and of the long-term management of digital information.

He developed the concept of the digital object architecture, a framework for identifying, locating and managing digital content so that it can be preserved and used over long periods and across changing technologies. The approach, including the handle system for persistent identifiers, has been applied to the management of scientific data, publications and other digital resources. His later career has thus extended his concern for interoperability from packets to information itself.

Recognition and Legacy

Kahn shared the Turing Award with Vint Cerf in 2004 for their work on internetworking, and he has received the Presidential Medal of Freedom, the National Medal of Technology and Innovation, and many other honours. He has served on numerous advisory bodies concerned with networking, information policy and national science, and he has been a persistent advocate for the open, interoperable character of the global network.

He is remembered as the co-designer of TCP/IP and as the originator of the open-architecture idea that gave the internet its capacity to grow by absorbing new networks. Together with Cerf he laid down the technical principles that allowed a small experimental system to become a worldwide infrastructure. His later work on digital objects reflects the same concern, that information should move and endure across boundaries.

See also

• TCP/IP
• Packet switching
• Digital object architecture
• Corporation for National Research Initiatives