The BBVA Foundation Frontiers of Knowledge Award goes to Leonard Kleinrock, who made the Internet possible by devising the most efficient way to share data and transmit information

Responsible for establishing the first remote connection between two computers, Kleinrock’s theoretical and technological contribution is foundational, in the view of the prize jury. Without his development of queueing theory and data packet switching, there could have been no Internet as we know it today. His idea of breaking down messages and using all available channels to transmit the resulting data packets proved the most robust way to organize information traffic.

On October 29, 1969, as part of the ARPAnet project funded by the United States Department of Defense, the first ever host-to-host connection was made, laying the groundwork for the future Internet: two computers several kilometers apart, in UCLA and the Stanford Research Institute (SRI), connected by a 50 kb/s line that was then considered high-speed, prepared to transmit the word “login”. At the first attempt, the SRI received only the “l” and “o” before the system crashed. But a short time later, the message came through and the first ARPAnet link was established. Kleinrock was in charge of the operation, chosen for the theoretical background he was able to provide.

His contributions rested on a central idea: the possibility to maximize resource sharing by the users of a communication network. Kleinrock saw that this was an indispensable pre-condition to get computer networking off the ground, and had in fact worked on the problem in the course of his doctoral studies.

The solution he turned to was a mathematical tool called queueing theory, which studies how to manage a network with optimal efficiency by juggling resources and users. Kleinrock was then able to develop this theory for the specific case of a data-sharing network. This work led him to packet switching technology, which, as the jury explains, is “one of the basic technologies behind the Internet.”

Kleinrock (New York, 1934), Distinguished Professor of Computer Science at the University of California, Los Angeles (UCLA) declared himself “thrilled and honored” on being informed by phone of the award, which was a “wholly unexpected surprise.” He continues supervising students and is currently engaged in a research project that looks precisely at “what it was about the environment of the 1960s and 1970s that allowed the creation of such wonderful innovations.”

His passion for engineering was sparked at the age of 6, when he built a crystal radio following the plans found in the pages of a Superman comic. Two decades later, in the early 1960s, he was doing a doctorate in electrical engineering and computer science at Massachusetts Institute of Technology. A disciple of Claude Shannon (regarded as the founding father of information technology), he elected to chart his own course and grapple with the problem of “how to get computers to talk to each other.”

“Of course it was something in the air, that had been there for some time – Kleinrock refers in passing to the work of Nikola Tesla at the start of the 20th century – but it was not the goal of many research teams.” In his PhD thesis, in 1962, he defended the imperative of sharing network resources and developed his application of queueing theory.

He offers an example illustrating the importance of network efficiency: “In a phone conversation, the line is exclusively dedicated to both users, even when they’re not speaking. I realized that a data network built in that way would be inefficient and prohibitively expensive.” It would be like a freeway network, he adds, that could only be used by one vehicle at a time.

His development of queueing theory enabled network capacity to be shared through the application of packet switching: each message is broken down into small, equal-sized blocks and transmitted over the network by what we now call a router – the backbone of Internet, present in every connected home. The idea is for these small data packets to occupy all the free space within the connection so they arrive faster than a single large packet and without problems of congestion.

Another example drawn from daily life: a supermarket queue would operate more efficiently – in terms of each customer’s waiting time – if those with the smallest baskets paid first. An analogy for how packet switching works is that each customer pays the same small number of items each time a checkout becomes free, reducing the average waiting time of all those in the queue.

At the time of that first ARPAnet connection, in 1969, Kleinrock had never seen his theories tested in practice, though a series of simulations had convinced him they would work. And the word “login” would prove him right.

Starting from Kleinrock’s work, queueing theory has found application in countless domains, as the jury points out: “The development of queueing theory, that allowed the disruptive transition from circuit switching (as used in analog telephone networks) to packet switching, has great significance not only for the Internet but also for many other fields such as traffic control, logistics, manufacturing and transportation. In all these applications queueing theory leads to significant reduction of waiting times.”

“The global nervous system of the world”

Even before the successful transmission of 1969, Kleinrock had outlined his vision of a “permanently available” future network, open to everyone and as “invisible” as electricity. Nowadays, he is convinced that the Internet’s impact will run deeper still: he predicts an everyday environment “full of cameras, sensors and small wearable devices,” that are continuously gathering and sending data on us all: “When I enter a room, the room will know it, and I’ll be able to ask it where I left my book or keys,” he predicts. “The Internet will become the global nervous system of the world.”

Of course this technology will not be without its drawbacks in matters like security or privacy. “Unfortunately loss of privacy is a done thing, we give up our privacy the moment we open an email account or start carrying a cell phone.”

Information and Communication Technologies jury

The jury in this category was chaired by George Gottlob, Professor of Computer Science at the University of Oxford (United Kingdom), with Ramón López de Mántaras, Director of the Artificial Intelligence Research Institute of the Spanish National Research Council (CSIC) acting as secretary. Remaining members were Rudolf Kruse, Head of the Department of Knowledge Processing and Language Engineering at Otto von Guericke University Magdeburg (Germany), Mateo Valero, Director of the Barcelona Supercomputing Center (Spain) and Joos Vandewalle, emeritus professor in the Department of Electrical Engineering (ESAT) at KU Leuven (Belgium).