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Digital Packet-Switching

Baran Paul Baran, computer technologist and entrepreneur, was responsible for one of the fundamental concepts that enables today's advanced computer networking systems: digital packet-switching. As such, he has sometimes been referred to as one of the "grandfathers of the Internet."

Baran was born in Poland in 1926. In 1928, his family moved to the United States and Baran spent much of his childhood helping out with the family grocery store in Philadelphia. After high school he attended Drexel University where he earned a degree in electrical engineering. When he left Drexel, Baran took a job as a technician at the Eckert-Mauchly Computer Corp. where he worked on Univac, the world's first computer. Soon after he married and moved to Los Angeles to work at the Hughes Aircraft Company. He began taking night classes at UCLA and earned a master's degree in engineering in 1959.

That year, Baran left Hughes to work for the computer science department in the mathematics division of the Rand Institute, a nonprofit research and development organization. At that time Rand focused on Cold War-related military problems, and Baran became interested in the survival of communication networks in the event of a nuclear attack. It was then that he conceived of the Internet and digital packet switching, which allows pieces of information to be divided into small packets of data that are addressed, sent to a specific destination, and then reassembled.

Baran had been working off the idea that the U.S. had to be able to survive a first strike from the Soviet Union and still be able to launch a counter-attack. Baran thought he could design a more powerful communication network by using digital computers and by introducing redundancy. Although he faced skepticism, Baran persevered. He studied the brain and found that it can recover lost functions by bypassing a dysfunctional region; it does so by not solely relying on a single set of dedicated cells for a given function. He thought he might be able to apply this principle to the design of a communication network.

Thus, Baran suggested a distributed network–"a communication network which will allow several hundred major communications stations to talk with one another after an enemy attack." This type of system would have no centralized switch. He also had the idea to divide messages into "message blocks" before sending them out across the network. Each block would be sent separately and rejoined into a whole when they were received at their destination. This concept later came to be known as packet-switching. Years later, Lawrence Roberts was beginning work on the ARPANET at MIT when he heard of Baran's ideas. He was designing a network both to facilitate communications between ARPA researchers and to allow them to use remote computing resources effectively. He decided to adopt Baran's distributed network and packet-switching schemes, and Baran became an informal consultant for the ARPANET project, which eventually led to what we now call the Internet.

Baran now lives in Atherton, Calif., with his wife. Baran serves as board chairman for Com21 Inc., which he founded in 1992. Com21 Inc. makes cable modems for high-speed, high-bandwidth Internet access. This company is one of a number of high-tech firms started by Baran over the years. He founded six companies in Silicon Valley including Cable Data Associates, established in Menlo Park in 1974. Telebit, his second company, was acquired by Cisco Systems. Equatorial Communications was acquired by Comtel and then acquired by GTE. Packet Technologies became StrataCom and again was subsequently acquired by Cisco Systems. Baran also co-founded Metricom International with Paul Allen. He is a co-founder of the Institute for the Future, a Life Fellow of the IEEE and a Fellow of the AAAS

[April 2001]

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