The demonstration involved sending two video streams—one marked for priority service and the other unmarked and routed as usual—over the Internet from Berkeley to Argonne in Illinois. Sharing an intentionally congested path, the priority-marked stream moved at eight frames per second, while the standard version transmitted just one frame per second.

The test was a key milestone in the development of a broad set of capabilities called "Differentiated Services" which are considered necessary if the Internet is to be able to provide different levels of service on demand to its network customers.

Typically, Internet users encounter a wide variety of cybertraffic conditions, ranging from free-flowing traffic to peak-hour jams to complete stalls. With Internet traffic growing by 400 percent annually, such congestion is increasing, leaving many users wishing for a more reliable level of service. The current quality of service, called "best effort," often leaves room for improvement.

Differentiated services will replace "best effort" by providing specialized services for Internet users who are willing to pay for it. One means of providing differentiated services is through a technology called "class-based queuing" developed at Berkeley Lab. The idea is similar to reserving a first-class, business class or coach seat on a commercial airline.

The new differentiated services technology is expected to demonstrate to industry how different levels of quality of service can be implemented and deployed on a practical basis. The technology is also expected to make it significantly easier to send audio and video signals across the Internet.

Achieving this improved level of service is essential to the work of the Department of Energy, which is pioneering the use of various technologies to allow scientists at more than 30 DOE national labs to share access to some of the nation's most advanced research facilities. Having connections that can disrupt real-time research collaborations in such fields as biomedical research or environmental restoration can result in both human and financial costs. Reliable connections allow researchers around the nation to make effective use of the some of the world's top scientific facilities.

The DOE already has one of the fastest and most reliable "backbone" networks of the Internet—the Energy Sciences Network, or ESnet. Scientists at Berkeley and Argonne regularly rely on ESnet to conduct collaborative research in structural biology, materials science and physics.

"For more than a decade, DOE computer scientists have helped develop technologies that have brought the Internet to the level it is today, and differentiated services is another key step toward tomorrow's network capabilities," says C. William McCurdy, head of the Computing Sciences organization at Berkeley Lab.

Although the idea of differentiated services is simple, coming up with the enabling technology was more difficult. Because the Internet is actually made up of millions of interconnected networks, the technology had to be able to scale up to work across the entire system. Hardware also had to be adapted to differentiate between different levels of priority for Internet traffic.

The link between Berkeley and Argonne uses new software to recognize specially marked data packets so that the various networks and Internet routers will give them priority over packets which are not similarly labeled. In limited tests last November, Lab computer scientists successfully proved that the priority-marked packets were routed through points of congestion, while similar data in unmarked packets were lost.

The software for marking the priority packets was developed at Berkeley Lab. Using this software, a policy decision of whom to give priority to is translated into special router commands to mark the appropriate packets for priority delivery. This work, as well as class-based queuing and many of the original key ideas for differentiated service, stems from research done by Van Jacobson and his Network Research Group at Berkeley Lab.