Leonard Kleinrock
Leonard Kleinrock, (born June 13, 1934 in New York) is a computer scientist, and a professor of computer science at UCLA's Henry Samueli School of Engineering and Applied Science, who made many significant contributions to the field of computer networking, particularly to the theoretical side of computer networking. He also played an essential role in the evolution of the ARPANET at UCLA. Kleinrock graduated from the famed Bronx High School of Science in 1951, and earned a Bachelor of Electrical Engineering degree in 1957 from the City College of New York, and a master's degree and a Ph.D.in electrical engineering & computer science from the Massachusetts Institute of Technology in 1959 and 1963 respectively.
His most familiar and substantial work is his early work on queueing theory, which has applications in numerous areas, among them as a central mathematical background to Packet Switching, the basic technology behind the Internet. His initial contribution to this discipline was his doctoral thesis in 1962, published in book form in 1964.
He has represented this work as: Setting out to do something "really important" and "not what the rest of the pack was doing," Kleinrock viewed the computers being employed for research, and arrived upon the simple insight that these machines were "gonna have to talk to each other one day." Thus began research on what would subsequently be called "packet-switching" and "queueing theory".
A lot of of Kleinrock's initial thoughts came from brainstorming about the most effective way for students and researchers at MIT and the associated Lincoln Laboratories to most efficiently share computer time. "Computers burst data, they transmit then they stop a while, while they're thinking or processing or whatever. And in those days data communication lines were really expensive," he said. "The idea was, don't dedicate a resource to somebody -- when I was sitting there, scratching my head, that machine was idle, I'm not using it. You want to do it in dynamic fashion: whoever needs it gets it now. If you're not using it, let somebody else in." Queueing Theory was essentially the idea that a single communication line should process multiple blocks of data from multiple sources on a first-come, first-serve basis. Packet-switching permitted the information to be placed orderly in the queue, by beating the data into digestible digital packets at the source, labeling each with directions and instructions, all in a standard language understood throughout the network.
A key assumption from the outset was that the network would not be centralized, or hierarchical, and would use "alternate dynamic routing" to direct its packets whichever way worked most favorable at the time. "I decided that you want to distribute the control, that no one node would control the network, that everybody would share," he said. "So if somebody dies, the rest of network works. Which means these nodes are constantly looking for the best paths." It was magnificent work, but Kleinrock's ideas and models of computer networking went for the most part unnoticed for the next seven years.
In 1966, his friend Lawrence Roberts joined the IPTO and in October, 1968, gave a contract to Kleinrock's NMC as the ideal group to execute ARPANET performance measurement and locate areas for improvement. In honour of Kleinrock's innovative work, UCLA was selected to receive the first "node" of the network, and the professor quickly collected a staff to prepare for the connection between a refrigerator-sized "Interface Message Processor" and a smaller department computer. The packet-switching concept was incontrovertibly proven on Sept. 2, 1969. The network soon extended to Stanford Research Institute, UC Santa Barbara and the University of Utah, then to seven more universities by the succeeding summer. "ARPAnet" was on its way.
Kleinrock was handed the job of measuring and testing the network once it was functional, so he arranged his team in several units (such as "hardware" and "software") and gave them assorted problems to puzzle on, like making a "host-to-host protocol" to create a common language for Internet Providers to operate applications on varied computers and computer networks. These graduate students and programmers, laboring in obscurity, advanced to define the parameters of the Internet over the following two decades.
Kleinrock has remained active in the research community, and has published more than 200 papers and authored six books. He has likewise been dynamic in federal policy making with the National Research Council's Computer Science and Telecommunications Board (CSTB) committee.
He has accepted numerous professional awards. Kleinrock was chosen to receive the prestigious National Medal of Science, the nation's highest scientific honor, from President George W. Bush in the White House on September 29, 2008.