LEN KLEINROCK on the Origins of the Internet: "This is login"

Petrie: But your design is based on your simulation?

Kleinrock: The simulation served to show the accuracy of the independence assumption. The design procedure is based on an analytic fit to tariff data. It turns out that the design problem was really very simple; in fact, once you have the analytic fit, you can do an exact analysis for the channel capacity assignment.

Suppose you have so much total capacity. Where do you put it in a network to minimize the average delay? How many bits per second do you put in each lane? To do this, you should know the traffic matrix. Once you have that, my simplest formulation led to what I called the optimum square root channel capacity assignment, and I generalized that to far more complex formulations.

Petrie: How did you generate a workload in your simulation?

Kleinrock: In the simulation I chose a variety of workloads. They were randomly generated, uniformly generated, generated with hot spots, and all the rest. I tried a variety of streaming stuff. I tested over a whole range. And so my thesis, which was filed in 1962, became a book that was published by McGraw-Hill in 1964. Recall that my first articles came out in 1961. I actually started work on packet switching in 1959. I mention the date because that's before other work that has been given credit for the invention of packet switching. I looked at the pure analytical case and had the exact formulation, and an analytic solution proved correct by simulation.

I also studied the effect of slicing things up into small pieces. This time-slicing algorithm showed the effectiveness, i.e., the gains in response time, that you get from "packetization." Of course, the word packet was not used in the data network field until the late 1960's when Donald Davies coined it for this application.

Petrie: But it was published; when was the article published?

Kleinrock: The first article was in RLE Report, Research Laboratory for Electronics Report in July of 1961. That predated everybody else's stuff. My thesis was handed in December of 1962.

Petrie: How much of your analysis eventually made it into the design of Arpanet?

Kleinrock: Well that's the other part of the question, because we started this conversation with you saying I had developed my ideas 10 years before Arpanet. The genealogy is this: I had some very well-known PhD classmates at MIT. One of them was Larry Roberts. Others included Ivan Sutherland, Tom Kailath, and Jacob Ziv.

Petrie: In the same class?

Kleinrock: Well the same group, going through together. I don't know who else you would know, but anyway, a powerful group of guys. You know, Claude Shannon, the father of information theory, was on my committee. It was a wonderful time. Larry Roberts, a very close friend of mine to this day, is a brilliant guy, and he did his work on picture processing. When I graduated I went directly to UCLA. My entire graduate education was fully funded by the MIT Lincoln Laboratory through their staff associate program. I worked for them in the summers. I also worked for them for six months after handing in my dissertation. They encouraged everyone to examine the market for research positions, just to see what's out there. They were very generous. As it turns out, I was offered this terrific job at UCLA. Lincoln Lab was sincere in their encouragement for new graduates to find the best positions possible, so I accepted the UCLA faculty position. Larry stayed on at Lincoln Lab. He was also a staff associate.

Now the name Licklider comes into the picture. Let me tell you about ARPA. Do you know the Sputnik story?

Petrie: No.

Kleinrock: In 1957 the Russians launched Sputnik, the first space satellite, and caught us with our pants down. The United States government said, "We can't ever let that happen again," so in 1958 they formed the Advanced Research Projects Agency. And they started doing work in a variety of areas, including some very early computer work. In 1963 they created an official office for computer research, the Information Systems Technology Office, ISTO. It's called ITO [Information Techniques Office] now.

J.C.R. Licklider was the first head there. He was the head before it was official. He was a visionary with a background in psychology. Now that time, the 60's, was the era of timesharing. Every time ARPA came to a new investigator and said we want you to do research for us, the investigator would say "fine, you want me to do computer research? Buy me a computer". So they bought him a computer. After a while, it got a little old, because every guy that got a computer made something special out of it. And every time a new one was bought, they wanted the capability of all those others. So Licklider conceived the idea of what he called "the galactic network." He actually used that word. He wanted to create a network whereby if you had some unique application, others could share it through a network. That was his motivation. He was the only one who had that long-term vision. Now of course I don't know if he foresaw what we have today. But he was thinking much further ahead than anybody else. None of the rest of us down in the trenches could see it.

Petrie: It seemed utterly impossible.

Kleinrock: You have to remember that PCs weren't invented yet. So Licklider wanted to have a network developed. He brought in a fellow named Bob Taylor to take over the office, and he stepped aside. But he influenced Bob to make a network happen. Bob Taylor hired Larry Roberts to come to the office and oversee his operation. This was in 1966. Larry said, "I'm going to get Len Kleinrock, since he knows just how to do this." So he brought me in, not to the office, but to the project, while I was at UCLA.

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