The expenditure milestone points that can be
ear-marked for system evaluation would occur at about the
$1.25-million level (during the Study and Research Phase),
after the $5-million point (at the conclusion of the entire
Study and Research Phase), at the $11.6-million level (at the
end of the Design Phase), at the $15.7-million mark (at the
end of the Test Phase), at the $21.7-million level (at the end
of the Development Phase), and at the $23.7-million point (at
the end of the Final Test Phase). Thus, there are
many early opportunities to reevaluate and redirect this
program upon discovery of unforeseen difficulties or better
alternative approaches.
- Paul Baran, On Distributed Communications,
Volume XI, 1964. |
Paul Baran developed the field of packet
switching networks while conducting research at the historic
RAND
organization, a concept embedded in the design of the ARPANET
and the standard TCP/IP
protocol used on the Internet today.
Paul Baran's packet switching story starts at the Research And
Development (RAND) research organization. RAND was founded in Santa
Monica, California, soon after the second world war to help maintain
the unique system analysis and operations research skills developed
by the US military to manage the unprecedented scale of planning and
logistics during that global conflict. RAND still maintains a high
proportion of research staff with advanced degrees, and provides an
extensive research capability capable of tackling a wide range of
problems for governments and industry.
In 1959, a young electrical engineer named Paul Baran joined RAND
from Hughes Aircraft's systems group. The US Air Force had recently
established one of the first wide area computer networks for the SAGE
radar defence system, and had an increasing interest in survivable,
wide area communications networks so they could reorganize and
respond after a nuclear attack, diminishing the attractiveness of a
first strike option by the Soviet Union.
Baran began an investigation into development of survivable
communications networks, the results of which were first presented
to the Air Force in the summer of 1961 as briefing B-265, then as
paper P-2626, and then as a series of eleven comprehensive papers
titled On Distributed Communications in 1964.
Baran's study describes a remarkably detailed architecture for a
distributed, survivable, packet switched communications network. The
network is designed to withstand almost any degree of destruction to
individual components without loss of end-to-end communications.
Since each computer could be connected to one or more other
computers, Baran assumed that any link of the network could fail at
any time, and the network therefore had no central control or
administration.
Baran's architecture was well designed to survive a nuclear
conflict, and helped to convince the US Military that wide area
digital computer networks were a promising technology. Baran also
talked to Bob Taylor and J.C.R.
Licklider at the IPTO
about his work, since they were also working to build a wide area
communications network. Baran's 1964 series of papers then
influenced Roberts
and Kleinrock
to adopt the technology for development of the ARPANET
network a few years later, laying the groundwork that leads to its
continued use today by TCP/IP on the Internet today..
In another of those scientific synchronicities, Baran's packet
switching work was strikingly similar to the work performed
independently a few years later by Donald Davies at the National
Physical Laboratory, including common details like a packet
size of 1024 bits. This idea was almost waiting to be discovered.
Baran later left RAND to become an entrepreneur and private
investor in the early 1970's, and founded Metricom, co-founded
Com21.com, and co-founded the Institute for the Future.
Paul Baran has also received numerous awards, including the IEEE
Alexander Graham Bell Medal, and the Marconi International
Fellowship
Award.