Paul Baran was a Polish-born American engineer who was a pioneer in the
development of computer networks. He was one of the two independent inventors of
packet switched computer networking, and went on to start several companies and
develop other technologies that are an essential part of modern digital
communication. Early life
Paul Baran was born in Grodno on April 29, 1926. He was the youngest of three
children in a Polish-Jewish family, with the Yiddish given name "Pesach". His
family moved to the United States on May 11, 1928, settling in Boston and later
in Philadelphia, where his father, Morris "Moshe" Baran, opened a grocery
store. He graduated from Drexel University in 1949, with a degree in
electrical engineering. He then joined the Eckert-Mauchly Computer Company,
where he did technical work on UNIVAC models, the first brand of commercial
computers in the USA. In 1955 he married Evelyn Murphy, moved to Los Angeles, and
worked for Hughes Aircraft on radar data processing systems. He obtained his
master's degree in engineering from UCLA in 1959, with advisor Gerald Estrin
while taking night classes. His thesis was on character recognition. While
Baran initially stayed on at UCLA to pursue his doctorate, a heavy travel and
work schedule forced him to abandon his doctoral work.
Packet switched network design After joining the RAND Corporation in
1959, Baran took on the task of designing a "survivable" communications
system that could maintain communication between end points in the face of damage
from nuclear weapons. At the time of the Cold War, most American military
communications used high frequency connections which could be put out of
action for many hours by a nuclear attack. Baran decided to automate RAND
director Franklin R. Collbohm's previous work with emergency communication over
conventional AM radio networks and showed that a distributed relay node
architecture could be survivable. The Rome Air Development Center soon showed
that the idea was practicable. Using the mini-computer technology of
the day, Baran and his team developed a simulation suite to test basic
connectivity of an array of nodes with varying degrees of linking. That is, a
network of n-ary degree of connectivity would have n links per node. The
simulation randomly 'killed' nodes and subsequently tested the percentage of
nodes that remained connected. The result of the simulation revealed that
networks where n ≥ 3 had a significant increase in resilience against even as
much as 50% node loss. Baran's insight gained from the simulation was that
redundancy was the key. His first work was published as a RAND report in 1960,
with more papers generalizing the techniques in the next two years.
After proving survivability Baran and his team needed to show proof of concept
for this design such that it could be built. This involved high level
schematics detailing the operation, construction, and cost of all the
components required to construct a network that leveraged this new insight
of redundant links. The result of this was one of the first store-and-forward
data layer switching protocols, a link-state/distance vector routing
protocol, and an unproved connection-oriented transport protocol.
Explicit detail of these designs can be found in the complete series of reports
On Distributed Communications, published by RAND in 1964.
The design flew in the face of telephony design of the time, placing inexpensive
and unreliable nodes at the center of the network, and more intelligent
terminating 'multiplexer' devices at the endpoints. In Baran's words, unlike the
telephone company's equipment, his design didn't require expensive "gold
plated" components to be reliable. This Distributed Network that Baran
introduced was intended to route around damage. It provided connection to others
through many points, not one centralized connection. Fundamental to this scheme
was the division of the information into "blocks" before sending them out across
the network. This enabled the data to travel faster and communications lines
to be used more efficiently. Each block was sent separately, traveling different
paths and rejoining into a whole when they were received at their destination.
= Selling the idea = After the publication of On Distributed
Communications, Paul Baran presented the findings of his team to a number of
audiences, including AT&T engineers. In subsequent interviews Baran mentioned
how the AT&T engineers scoffed at his idea of non-dedicated physical circuits
for voice communications, at times claiming that Baran simply did not
understand how voice telecommunication worked.
Donald Davies at the National Physical Laboratory in the United Kingdom also
thought of the same idea and implemented a trial network. While Baran used the
term "message blocks" for his units of communication, Davies used the term
"packets" as it was capable of being translated into languages other than
English without compromise. He applied the concept to a general-purpose
computer network. Davies' key insight came in the realization that computer
network traffic was inherently "bursty" with periods of silence, compared with
relatively constant telephone traffic. It was in fact Davies' work on packet
switching, and not Baran's, that initially caught the attention of the
developers of ARPANET, at a conference in Gatlinburg, Tennessee, in October
1967. Baran was happy to acknowledge that Davies had come up with the same
idea as him independently. In an e-mail to Davies he wrote
You and I share a common view of what packet switching is all about, since you
and I independently came up with the same ingredients.
Leonard Kleinrock, a contemporary working on analyzing data flow, also
reached similar conclusions when he developed a theoretical basis for the
operation of packet networks in his proposal for a Ph.D. thesis in 1961. He
published his ideas in that year. However, Kleinrock's contribution to
packet switching is disputed by some, including Baran and Davies.
In 1969, when the US Defense Advanced Research Projects Agency started
developing the idea of an inter-networked set of terminals to
share computing resources, the reference materials which they considered included
Baran and the RAND Corporation's "On Distributed Communications" volumes. The
resiliency of a packet-switched network that uses link-state routing protocols
used on the Internet stems in some part from the research to develop a network
that could survive a nuclear attack. Later work
In 1968 Baran was a founder of the Institute for the Future, and was then
involved in other networking technologies developed in Silicon
Valley. He participated in a review of the NBS proposal for a Data Encryption
Standard in 1976, along with Martin Hellman and Whitfield Diffie of Stanford
University. In the early 1980s, Baran founded PacketCable, Inc, "to support
impulse-pay television channels, locally generated videotex, and packetized voice
transmission". PacketCable spun off StrataCom to commercialize his packet
voice technology for the telephony market. This technology led to the first
commercial pre-standard Asynchronous Transfer Mode product. He founded
Telebit after conceiving its discrete multitone modem technology in the
mid-1980s. This was one of the first commercial products to use Orthogonal
frequency-division multiplexing, which was later widely deployed in DSL modems
and Wi-Fi wireless modems. In 1985, Baran founded Metricom, the first
wireless Internet company, which deployed Ricochet, the first public
wireless mesh networking system. In 1992, he also founded Com21, an early
cable modem company. Following Com21, Baran founded and was president of
GoBackTV, which specializes in personal TV and cable IPTV infrastructure
equipment for television operators. Most recently he founded Plaster Networks,
providing an advanced solution for connecting networked devices in the home
or small office through existing wiring. Baran extended his work in packet
switching to wireless-spectrum theory, developing what he called "kindergarten
rules" for the use of wireless spectrum. In addition to his innovation in
networking products, he is also credited with inventing the first doorway gun
detector. He received an honorary doctorate when
he gave the commencement speech at Drexel in 1997.
Death Baran died in Palo Alto, California at
the age of 84 on March 26, 2011, due to complications from lung cancer. Upon his
death James Thomson, the president of RAND, stated that "Our world is a better
place for the technologies Paul Baran invented and developed, and also because
of his consistent concern with appropriate public policies for their
use." One of the fathers of the internet, Vinton Cerf, stated that "Paul
wasn't afraid to go in directions counter to what everyone else thought
was the right or only thing to do." According to Paul Saffo, Baran also
believed that innovation was a "team process" and he didn't seek credit for
himself. On hearing news of his death, Robert Kahn, co-inventor of the
Internet, said: "Paul was one of the finest gentlemen I ever met and creative
to the very end." Awards and honors
IEEE Alexander Graham Bell Medal Marconi Prize
Nippon Electronics Corporation C&C Prize Bower Award and Prize for Achievement in
Science Fellow of the American Academy of Arts
and Sciences Fellow of the Computer History Museum
"for fundamental contributions to the architecture of the internet and for a
lifetime of entrepreneurial activity." National Inventors Hall of Fame
National Medal of Technology and Innovation
UCLA Engineering Alumnus of the Year Internet Hall of Fame
References External links
"Paul Baran Invents Packet Switching". www.livinginternet.com. William Stewart.
January 17, 2011. Retrieved March 31, 2011.
O'Neill, Judy E.. "Oral history interview with Paul Baran". Minneapolis,
MN: Charles Babbage Institute. Retrieved March 31, 2011. A 44-page transcript in
which Baran describes his working environment at RAND, his initial
interest in survivable communications, the evolution of his plan for
distributed networks, the objections he received, and the writing and
distribution of his eleven-volume work, On Distributed Communications. Baran
discusses his interaction with the group at ARPA who were responsible for the
later development of the ARPANET. Harris, Trevor, Who is the Father of the
Internet? The case for Donald Watts Davies, retrieved 10 July 2013
Ryan, Patrick S.. "SSRN-Wireless Communications and Computing at a
Crossroads: New Paradigms and Their Impact on Theories Governing the
Public's Right to Spectrum Access". Journal on Telecommunications & High
Technology Law 3: 239–274. ISSN 1543-8899. OCLC 66137086. Retrieved
March 31, 2011. This describes Paul Baran's development of packet switching
and its application to wireless computing.
"Convergence: Past, Present, and Future: Paul Baran Addresses CableLabs® Winter
Conference". Louisville, CO: Cable Television Laboratories, Inc. February
1999. Archived from the original on May 25, 2011. Retrieved March 31, 2011. A
transcript of Baran's keynote address at the Countdown to Technology 2000 Winter
Conference that includes a photo. Brown, Bob. "Paul Baran, Internet and
packet switching pioneer, is mourned". Framingham, MA: Network World, Inc.
Retrieved April 2, 2011. Baran credited with inventing packet switching in 1960s
against military backdrop "Paul Baran". Internet Pioneers at
ibiblio.org. Chapel Hill, NC: School of Information and Library Science and the
School of Journalism and Mass Communication at the University of North
Carolina at Chapel Hill. November 6, 2005. Retrieved April 2, 2011.
Gilder, George. "Inventing the Internet Again". Forbes ASAP 159: 106–120. ISSN
1078-9901. OCLC 173437996. Archived from the original on April 10, 2006.
Retrieved April 8, 2011.