Leonard Kleinrock

• Born: June 13, 1934
• Place of Birth: Harlem, New York City, NY

• Developer of the Internet
• Primary Field: Computer science
• Specialty: Internet
• Primary Company/Organization: University of California, Los Angeles

Introduction

Leonard Kleinrock's contributions to the Internet have been extensive on both the theoretical and practical levels. He has referred to himself as the father of modern data networking, a claim disputed by some. He conducted research into and enhanced the theoretical framework for packet switching, a technology that allows messages to be broken into smaller segments and then reassembled at the point where the message was to be sent. This method would allow faster transmission with the ability to share computer resources most effectively. On a practical level, Kleinrock and his staff at the University of California at Los Angeles (UCLA) supported the creation of the first major network, the Advanced Research Projects Agency Network (ARPANET), developing and implementing its first node at UCLA. He later developed other ideas on how the resulting Internet could be improved and has been an advocate for greater mobility, or what he calls “nomadic computing.”

Early Life

Leonard Kleinrock was born on June 13, 1934, in New York City. He has described how his later life was changed forever when, at the age of six, he was reading a Superman comic book. Inside the comic book was a set of instructions for making a crystal radio. After gathering the materials, he built the radio set, and, as he put it, an engineer was born. He continued to make radios and other projects and, given his interests, enrolled at the Bronx High School of Science.

He graduated from high school in 1951 and later that year began attending night school at the City College of New York. He graduated in 1957 with a bachelor's degree in electrical engineering. Kleinrock then went to the Massachusetts Institute of Technology (MIT), where he earned a master's degree in electrical engineering (1959) and a doctorate in computer science (1963). He received his PhD at MIT in the same year as his later colleague and codeveloper of the ARPANET, Larry Roberts, received his.

Upon graduating from MIT, Kleinrock joined the faculty at UCLA. In the years immediately after his arrival, Kleinrock's activities included the establishment of the Network Measurement Center (NMC), which, as a network measuring and development group, would play a large role in his own career as well as in the development of the ARPANET.

Life's Work

Kleinrock's major work can be divided into two significant areas. The first and most controversial is his claim to have developed the idea of packet switching as a means of transmitting messages. Packet switching was an important development in the effective transfer of data over networks. In the 1950s and 1960s, the capability of mainframe computers was limited. The standard procedure was to send a message in its entirety, a process that required a greater share of computer resources. At this time, gaining the maximum use by numerous users (time-sharing) was becoming the subject of increasing research, as it was looked upon as the only reasonable alternative to buying larger numbers of computers. Additionally, as nearly all communications technology at that time was developed with a thought toward military applications, the vulnerability of these long message strings was a point of concern. Packet switching meant that messages would be decomposed into “packets,” small portions of the message, then sent over the communication network to the destination, where the message would be reassembled.

Work on this concept had already been done from a theoretical perspective. Kleinrock produced papers in the early 1960s based on his doctoral research in queuing, which was important to the implementation of packet switching. What he claimed was not only that his work in computer science was important for the successful development of packet switching but also that he had, in essence, invented it.

Kleinrock's role in the development of the Internet has, for some years now, been the source of controversy. That controversy began in the mid-1990s, when Kleinrock began to style himself as the “Inventor of Internet Technology” and posted his claims on his web page at UCLA. The claims were met with considerable skepticism because it was widely known that two other individuals, Donald Davies and Paul Baran, were considered to be the inventors of packet switching. They had not only defined what packet switching was in theory but also had coined the term packets for the bundles of data into which messages were broken and had actually built a prototype packet-switching network in the mid-1960s.

Davies contested Kleinrock's assertions of having developed the technology in a letter released after his death (his son saying that, because Davies was ill toward the end of his life, he had not wanted to engage in a battle at that time). In his letter, Davies strongly claims that Kleinrock made no real contribution to either the practical or the theoretical aspects of packet switching. Kleinrock's claim to have written about packet switching in 1961 was disputed not only by Davies but also by several authors who analyzed Kleinrock's work from that time; their conclusions lend credence to Davies' claim. Kleinrock's work in the early 1960s was based on his investigations into queuing, which does have a connection with the operation of packet switching.

Kleinrock's reply has been that while Baran and Davies did make contributions to the concept, the credit for developing packet switching should go to him. While some authors have noted the work done by Davies and Baran, Larry Roberts, who managed the development of ARPANET, has repeatedly come to the defense of Kleinrock and his claims.

The second part of Kleinrock's life work was in building ARPANET. He had already begun to establish himself as a leader in planning how networks might work and how they might be built. In 1961, he published a paper entitled “Information Flow in Large Communication Nets.” Three years later, he would write a book, Communication Nets, that attracted wide attention. One of those who read the book was his MIT classmate, Larry Roberts, who would become the project manager for the development of ARPANET.

ARPANET, a network that would be designed and developed through the auspices of the Defense Advanced Research Projects Agency (DARPA), was the result of conversations, exchanges of ideas, and papers during the early 1960s. J. C. R. Licklider's idea of a “galactic” network that would allow multiple users to communicate simultaneously found support among ARPA managers and scientists, including Roberts. The effort started under Roberts's direction in 1967, and the network of four computers, including one at UCLA that Kleinrock's NMC staff had assisted in developing, went into operation in October 1969.

Kleinrock and his group did not cease their affiliation with ARPANET after the successful implementation. A large part of the NMC's charter had been to test and suggest improvements to ARPANET. Through the 1970s, Kleinrock and his team worked on expanding the capabilities of the network, especially in terms of performance through stress testing and increasing the robustness of the network.

Personal Life

Kleinrock has published more than 225 papers and six books in the course of his career. He secured seventeen patents through 2011. In addition to his work at UCLA, Kleinrock has been active in private ventures. One of these is Nomadix, of which he is founder and chairman. Nomadix manufactures gateways that can more easily support the demands of what Kleinrock refers to as nomadic computing, or nomadicity. This nomadicity includes the increasing number of users who depend on public and visitor-based networks or who use Wi-Fi zones.

In 2004, Kleinrock made news when he stated that, as a UCLA principal investigator for DARPA, he would no longer accept any DARPA funding because of its new policy of not granting funding to projects in which not all the researchers were US citizens.

Kleinrock is a member of many professional organizations, such as the National Academy of Engineering, and he is a Fellow of the Association for Computing Machinery and the Institute of Electrical and Electronics Engineers (IEEE). He is an inaugural member of the Internet Hall of Fame, which was founded in 2012.

Kleinrock has also participated on several committees to investigate network issues. He has received many awards, including the Marconi Award, the IEEE Internet Millennium Award, the UCLA Outstanding Teacher Award, and the National Academy of Engineering's Charles Stark Draper Prize. It was this last award, received with Larry Roberts, Robert Kahn, and Vinton Cerf, combined with his statements beginning in the mid-1990s about his role in developing the Internet, that created the controversy surrounding Kleinrock. President George W. Bush presented Kleinrock with the 2007 President's National Medal of Science, one of the nation's most prestigious prizes in science and technology, for "his fundamental contributions to the mathematical theory of modern data networks, and for the functional specification of packet switching, which is the foundation of internet technology...." In 2015, he received the international BBVA Foundation Frontiers of Knowledge Laureate award in information and communications technologies. In 2016, Kleinrock received the SIGMOBILE inaugural Test of Time award. He was elected to the National Academy of Sciences in 2024 and was the recipient of the 2024 IEEE Computer Society Computer Pioneer Award.

Director Werner Herzog made the film Lo and Behold: Reveries of a Connected World to profile the creation of the internet and its spread. Kleinrock appears in the 2016 film in the lab where the first message was sent. Kleinrock is a distinguished professor emeritus at UCLA, where he directs the UCLA Connection Lab and created the Internet Research Initiative in 2016.

Bibliography

Hafner, Katie. “A Paternity Suit Divides Net Pioneers.” New York Times. 8 Nov. 2001: n. pag. Print.

"Internet Pioneer Leonard Kleinrock Elected to National Academy of Sciences." University of California–Los Angeles, 8 May 2024, samueli.ucla.edu/internet-pioneer-leonard-kleinrock-elected-to-national-academy-of-sciences/. Accessed 16 Oct. 2024.

Kisliuk, Bill. "Werner Herzog Film Follows Internet from its Birth at UCLA." UCLA Newsroom, 5 Aug. 2016, newsroom.ucla.edu/stories/werner-herzog-film-follows-internet-from-its-birth-at-ucla. Accessed 16 Oct. 2024.

Kleinrock, Leonard. “Busting Loose.” Communications of the ACM Sept. 2001: 41–45. Print.

Kleinrock, Leonard. “Creating a Mathematical Theory of Computer Networks.” Operations Research 50.1 (2002): 125–31. Print.

Kleinrock, Leonard. “Nomadic Computing and Smart Spaces.” IEEE Internet Computing 4.1 (2000): 52–53. Print.

Kleinrock, Leonard. Queueing Systems. Volume 1: Theory, Volume 2: Computer Applications, Wiley, 1975–76.

Kurose, James F., and Keith W. Ross. Computer Networking: A Top-down Approach Featuring the Internet. Boston: Pearson/Addison Wesley, 2005. Print.

Salus, Peter H. Casting the Net: From ARPANET to Internet and Beyond. Reading: Addison-Wesley, 1995. Print.