New chair for computer science

Larry L. Peterson has been named chair of the Department of Computer Science. He succeeds David Dobkin, who was appointed dean of the faculty.

Larry Peterson is the new chairman of the Department of Computer Science. Photo by Frank Wojciechowski

Professor Peterson's research activities include optimizing the congestion control algorithm used in the Internet; improving operating system support for high-speed networks; designing new directory services used to discover network resources and services; developing new protocols for group communication; and building scalable Internet routers that can be dynamically configured to support new functionality.

He is one of the founders of PlanetLab, an experimental global network of computers that is expected to become a testing ground for a future generation of the Internet.

An overlay network

PlanetLab is designed to allow researchers to develop and test powerful new types of software that are not confined to a single computer but run on many computers at once, treating the global network, in a sense, as one large, widely distributed computer.

Once fully developed, such a network could yield many benefits, from faster downloads to more powerful search engines. A person watching an online video, for example, might receive it from many computers that work together to avoid congested parts of the Internet. Software that scans the entire Internet for malicious behavior would catch problems before they could be detected by a single computer at one particular site.

"If I can observe the behavior of the Internet from multiple vantage points, I can see what the traffic looks like, where the losses are and where the congestion is," Professor Peterson said.

In its initial stages, PlanetLab is expected to be most useful as a vehicle--open to any researcher in industry or academia--for testing globally distributed applications.

Previously, researchers relied on network simulation, or a cluster of computers in a single room or building. With PlanetLab, which is built onto the Internet as an "overlay" network, researchers have a real-life testing ground that would be impossible for any single institution or company to create, Professor Peterson said.

"The Internet is much flakier than a controlled machine room," he said. "And it's just not practical for any one researcher to have hundreds of machines spread all over the world."

The PlanetLab project began in March 2002 when researchers from several institutions met to discuss the idea. The founding group included David Culler of Intel and the University of California at Berkeley, Tom Anderson of the University of Washington, and Professor Peterson.

Corporate support

Intel, the world's largest computer chip maker and a manufacturer of networking products, provided seed grants of equipment to set up a network of nearly 200 computers hosted by 75 international institutions. The technology firms HP and Google also are joining the project and will commit resources to it.

Princeton University recently committed to hosting a formal consortium of PlanetLab users and developers. The University will provide administrative and technical support as the system grows toward a goal of 1,000 nodes worldwide.

"PlanetLab is unlike any other collaborative research effort I've been involved in," Professor Peterson said. "It has an energy much like that which existed in the earliest days of the Internet.

"Researchers are using PlanetLab as a platform for advancing their individual research agendas, but at the same time they are looking for opportunities to contribute to PlanetLab's core infrastructure.

"If I had to put my finger on the key idea in the architecture, it's that we have designed PlanetLab to provide a level playing field for innovation, and the research community has responded in force."

David Tennenhouse, vice president of the Corporate Technology Group and director of research at Intel, said Intel is excited to be a part of this global collaboration.

"PlanetLab researchers are going to unlock a new era of innovation on the Internet, bringing new services within milliseconds of their users around the world, and affecting the design of smart servers and embedded storage and network processors," Mr. Tennenhouse said. "We are simultaneously creating the engines of future Internet growth and learning about the new products that will be required to make them tick."

Patrick Scaglia, vice president and director of the Internet and Computing Platforms Research Center at HP Labs said HP is extremely excited about joining PlanetLab.

"It's a perfect example of collaborative research," he said. "Neither we, nor Intel, nor Berkeley, nor Princeton could create alone the next generation Internet that will be born in PlanetLab."

Internet evolution

PlanetLab researchers believe the project will help the Internet evolve beyond a simple structure for transmitting data from place to place and toward a system that can manipulate the data before and after it travels. It is a first step toward an Internet that has processing power built into the infrastructure of the network.

Because it is so decentralized, the Internet cannot change overnight. But if PlanetLab demonstrates value, companies that sell Internet hardware might begin to work aspects of the system into their products, Professor Peterson said.

PlanetLab is known as an overlay system because it builds on the basic infrastructure of the Internet.

The Internet itself began as an overlay system on top of the phone system and still depends in large part on wires and cables that were first designed for telephone communications.

"PlanetLab is plainly an idea whose time has come," said Vinton Cerf, one of the founders of the Internet and now senior vice president for architecture and technology at MCI. "While it is too early to tell what is likely to be discovered, it seems inescapable that this platform will furnish opportunities for innovative experiments."

Teaching tool

Professor Peterson said PlanetLab already has become a valuable teaching tool for both graduate and undergraduate students who study networks.

Courses at several universities have been built around the project, and he is teaching one this fall. Other Princeton researchers involved in the project are assistant professors Vivek Pai and Randy Wang.

"I'm very excited by the PlanetLab initiative," said Maria Klawe, dean of the School of Engineering and Applied Science. "It is a unique collaboration between academia and industry that has already produced a powerful tool for both teaching and research. I am particularly proud of Larry Peterson's team, which has been responsible for defining the architecture and building the key pieces of technology.

"Princeton is now stepping forward to create an academia-industry consortium to take PlanetLab to a significantly larger scale with enhanced core tools and technologies. This exemplifies the kind of leadership that our School of Engineering and Applied Science aspires to achieve."

Professor Peterson received his undergraduate degree in 1979 from the University of Nebraska at Kearney, and his master's degree and Ph.D. in computer science from Purdue University in 1982 and 1985, respectively.

He is a coauthor of Computer Networks: A Systems Approach, a networking textbook. He recently served as editor-in-chief of the ACM Transactions on Computer Systems, and has been on the editorial board for ACM/IEEE Transactions on Networking, the ACM Transactions on Embedded Systems, and the IEEE Journal on Selected Areas in Communications.

Professor Peterson joined the Princeton faculty in 1998 from the University of Arizona, where he was professor and head of the computer science department. There, Professor Peterson was recognized for his teaching abilities by being awarded the Distinguished Teaching Award for the College of Science at the University of Arizona in 1995.