How To Unclog The Internet? Put It In Reverse

Christopher Carothers, assistant professor of computer science, received a Faculty Early Career Development (CAREER) Award from the National Science Foundation to study reverse computation in the simulation and modeling of large-scale networks such as the Internet. Carothers, a Rensselaer faculty member since 1998, was awarded $375,000 over five years.

When used in large-scale systems, reverse computation -- literally running a program backward -- will allow network managers to backtrack to the source of congestion. Bandwidth demand and availability are doubling, but so-called "killer applications" such as Napster and SETI@home (where people enlist their home PCs in the search for extraterrestrial life) create intense Internet bandwidth demand and create Internet congestion.

Current techniques require managers to explore all possible paths to the congestion, a time-consuming effort. Carothers believes reverse computation will help network managers find trouble spots before congestion occurs. His techniques could decrease processing time by at least a factor of 10 if not more, depending on the complexity of the system, and aid in the rapid design of future network systems.

"Using this reverse technique will give us more than the 'best guess' scenarios we currently have when designing networks and simulation experiments," Carothers said. "We will also have the capability to quickly rule out events that are not connected to congestion."

The CAREER Award, aimed at young faculty members actively engaged in research and education, is one of the NSF's most competitive and prestigious awards.

Rensselaer Polytechnic Institute, founded in 1824, is the nation's oldest technological university. The school offers degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research and teaching. The Institute is especially well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.