Paul Baran (born Pesach Baran /ˈbærən/; April 29, 1926 – March 26, 2011) was a Polish-American engineer. He helped create computer networks and was one of two people who independently developed packet switching. This method is now the main way data is sent over computer networks worldwide. He also started several companies and created other technologies that are important for modern digital communication.

Early life

He was born in Grodno (then part of Poland, and now part of Belarus) on April 29, 1926. He was the youngest of three children in his Lithuanian Jewish family, and his Yiddish name was "Pesach." His family moved to the United States on May 11, 1928, and settled in Boston before later moving to Philadelphia. His father, Morris "Moshe" Baran (1884–1979), opened a grocery store. He graduated from Drexel University (formerly called Drexel Institute of Technology) in 1949 with a degree in electrical engineering. He then worked for the Eckert-Mauchly Computer Company, where he helped develop UNIVAC models, the first commercial computers in the United States. In 1955, he married Evelyn Murphy, moved to Los Angeles, and worked for Hughes Aircraft on systems that process radar data. He earned his master's degree in engineering from UCLA in 1959, with his advisor being Gerald Estrin, while taking night classes. His thesis focused on character recognition. Although Baran initially stayed at UCLA to complete his doctorate, a busy schedule with travel and work caused him to stop his doctoral studies.

Packet switched network design

In 1959, Paul Baran joined the RAND Corporation and worked on creating a communications system that could keep working even if parts of it were damaged during the Cold War. At the time, most military communications used high-frequency connections that could be destroyed for hours by a nuclear attack. Baran improved on earlier work by using a system with many relay points spread across the network. This design made the system more likely to survive damage. The Rome Air Development Center later confirmed that this idea was practical.

Baran and his team used small computers from that time to create a simulation. They tested how well a network with many connected points could stay linked even if some parts were removed. The simulation showed that networks where each point connected to at least three others were much more likely to stay functional even if half of the points were lost. Baran concluded that having extra connections, or redundancy, was the key to making the system strong. His first report on this work was published in 1960, and more detailed studies followed in the next two years.

After proving the system could survive damage, Baran and his team created detailed plans to build it. These plans included how the network would operate, what parts were needed, and how much they would cost. Their work led to the development of one of the first systems that stored and forwarded data, used a method to find the best routes for messages, and introduced a way to manage connections between devices. Full details of these designs were published in a series of reports titled On Distributed Communications by RAND in 1964.

Baran’s design was different from traditional telephone systems, which used expensive and reliable equipment in the middle of the network. Instead, his system used cheaper, less reliable devices in the center and more advanced devices at the ends of the network. This allowed the system to reroute messages around damaged areas. Information was divided into small parts before being sent through the network. This made communication faster and used lines more efficiently. Each part traveled separately, took different paths, and was reassembled at the destination.

After publishing On Distributed Communications, Baran shared his findings with groups like AT&T engineers. These engineers did not confuse him with Bell Labs engineers, who had provided Baran with technical details for the first T1 circuit used in his network design. Some AT&T engineers doubted the usefulness of his system for voice communication, saying he did not understand how telephone systems worked.

At the same time, Donald Davies in the United Kingdom also developed a similar idea. He used the term "packets" for the units of communication, which could be translated into other languages without losing meaning. Davies applied the concept to a general-purpose computer network. He noticed that computer traffic had long periods of no activity, unlike the steady flow of telephone calls. His work on packet switching caught the attention of ARPANET developers in 1967. Baran acknowledged that Davies had independently reached the same conclusion.

Leonard Kleinrock studied how messages moved through networks using math. His research, published in 1964, provided a theoretical foundation for message-switching systems. Later, he used this theory to study packet-switching networks. However, some experts, including Baran and Davies, argue that Kleinrock did not originate the concept of packet switching. Historians and the U.S. National Inventors Hall of Fame recognize Baran and Davies as the independent inventors of digital packet switching, which is used in modern computer networks like the Internet.

In 1969, the U.S. Advanced Research Projects Agency (ARPA) began building a network of connected computers to share resources. Their plans included studying Baran’s On Distributed Communications reports. The ability of packet-switched networks to survive damage, using routing methods still used on the Internet today, was partly based on Baran’s research to create a system that could function during a nuclear attack.

Later work

In 1968, Baran helped start the Institute for the Future. He later worked on other technologies related to networks in Silicon Valley. He wrote about computer systems and privacy. In 1976, he helped review a proposal for a Data Encryption Standard by the NBS, along with Martin Hellman and Whitfield Diffie from Stanford University.

In 1971, Baran predicted that people would use email at home. He estimated that such services could earn $707 million by 1989.

In the early 1980s, Baran started a company called PacketCable, Inc. to support technologies like impulse-pay television, locally created videotex, and packetized voice transmission. PacketCable, also known as Packet Technologies, later created a new company called StrataCom to develop his packet voice technology for telephone services. This technology led to the first commercial product using Asynchronous Transfer Mode before official standards were set.

In the mid-1980s, Baran started a company called Telebit after developing discrete multitone modem technology. This was one of the first products to use orthogonal frequency-division multiplexing, a method later used in DSL modems and Wi-Fi wireless modems.

In 1985, Baran started Metricom, the first company to offer wireless Internet. It launched Ricochet, the first public wireless mesh network. In 1992, he started Com21, an early company that made cable modems. Later, he founded GoBackTV, which focused on equipment for personal TV and cable Internet services. He also started Plaster Networks, which provided tools to connect devices at home or in small offices using existing wiring.

Baran expanded his work on packet switching to wireless communication, creating what he called "kindergarten rules" for using wireless spectrum.

In addition to his work on networking, Baran invented the first doorway gun detector.

In 1997, he earned an honorary doctorate after giving a speech at Drexel University.

Death

Paul Baran passed away in Palo Alto, California, on March 26, 2011, at the age of 84 due to complications from lung cancer. After his death, James Thomson, President of RAND, said, "Our world is better because of the technologies Paul Baran created and because he always cared about the right ways to use them."

Vinton Cerf, one of the fathers of the Internet, noted, "Paul was not afraid to take paths others thought were wrong or unnecessary." Paul Saffo explained that Baran believed innovation was a "group effort" and did not seek personal credit. When learning of Baran’s death, Robert Kahn, co-inventor of the Internet, said, "Paul was one of the most honorable people I ever met and remained creative until the end."

Awards and honors

• IEEE Alexander Graham Bell Medal (1990)
• Marconi Prize (1991)
• Nippon Electronics Corporation C&C Prize (1996)
• Bower Award and Prize for Achievement in Science (2001)
• Member of the American Academy of Arts and Sciences (2003)
• Member of the Computer History Museum (2005) "for important work in designing the Internet and for a lifetime of innovative business efforts."
• National Inventors Hall of Fame (2007)
• National Medal of Technology and Innovation (2007)
• UCLA Engineering Graduate of the Year (2009)
• Internet Hall of Fame (2012)