While fiberoptic cables carry data at the speed of light over the Internet backbone, the equipment that directs Internet traffic--the switches and routers that get data to the right places--still requires inefficient conversions of optical signals to electrical signals and back again. Keeping data in the optical domain during routing and packet switching would remove a major bottleneck, but requires fundamentally new networking technology. Researchers at the University of California, Santa Cruz, are part of the first large-scale project to tackle this issue.
Led by Lucent Technologies and its research and development arm, Bell Laboratories, and funded by a four-year, $12.5 million grant from the Defense Advanced Research Projects Agency (DARPA), the program aims to develop a high-capacity router based on all-optical technologies. The research team includes collaborators from UCSC, Lehigh University, and Agility Communications.
Anujan Varma, professor of computer engineering at UCSC, is working on developing the system architecture and algorithms for the new optical router technology. Bell Laboratories is responsible for the underlying optical device techologies. The proposed optical router is called the Integrated Router Interconnected Spectrally (IRIS).
"The IRIS system will be very different from current routers," Varma said. "It is quite a huge undertaking, but if it succeeds it will fundamentally change the nature of data communications."
With the volume of Internet traffic roughly doubling every year, the routers that process all that traffic will eventually have to have much higher capacities than those currently available. The high-capacity routers now on the market are bulky, expensive, and power-hungry, and building even higher-capacity routers with existing technologies will be difficult, Varma said. The IRIS program is taking a completely novel approach to the problem.
The work of Varma's group on the system architecture will help guide the team's technology development efforts by defining precisely the requirements for the optical devices. Most of the funding will go toward the development of the optical device technologies. Varma's group will receive about $750,000 of the DARPA grant.
A big concern for Varma is how the new system can be made compatible with the current Internet infrastructure.
"There is a big gap between the two technologies, so compatibility is a major challenge," he said.
There are even greater challenges on the technology development side. Many new optical technologies have been developed in recent years, but they are not yet at the point where they can be used to build the kind of system envisioned for IRIS, Varma said.
Data storage, in particular, is a critical problem for an optical router. A router needs to have internal memory where data are temporarily stored before being forwarded to a new destination. That is very hard to do optically, but researchers at Bell Laboratories have developed photonic integrated circuits that can, in effect, keep optical signals circulating around within the chip.
"The capacity is limited, but it is a good starting point," Varma said.
The IRIS program aims to have a small working prototype in four years. But it could be 10 to 20 years before a fully optical high-capacity router is ready for the market, Varma said.
"This is such a long term effort that industry is not going to fund it, so this is where government funding is needed," he said.
DARPA also plans to fund a second group to work on the same problem. The Internet itself grew out of an earlier DARPA program (ARPANET), and the agency is known for funding innovative and creative research projects.
Varma is well known in the networking industry for his research in the areas of high-speed switching and routing, optical networks, traffic scheduling, and congestion control. An earlier project in which he worked with researchers at UC Berkeley and Stanford led to a successful prototype of an optical switch.
"That was similar to what we are doing now, but on a smaller scale," Varma said.
He has also worked with Bell Labs researchers on previous projects, and the IRIS team includes one of his former students, Dimitrios Stiliadis. Stiliadis earned his M.S. and Ph.D. degrees in computer engineering at UCSC and is now a Distinguished Member of the Technical Staff at Bell Labs.
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Note to reporters: You may contact Varma at (831) 459-3505 or varma@soe.ucsc.edu.
