was a low-cost computing platform for those who wanted to write programs. Like the Internet, the PC was immediately seen as valuable by a small user community that sustained its market. But it was not until the invention of the spreadsheet application that the popularity of PCs would rise rapidly. Similarly, in the networking world, the World Wide Web dramatically increased the popularity of the Internet, whose size went from roughly 200,000 computers in 1990 to 10 million in 1996, to a projected 100 million in 2001. Although the inventors of these applications were technically sophisticated, they were not part of the research community that invented the underlying disruptive technology. These examples illustrate an important caveat: It is hard to know up front what the “killer app” for new enabling technologies will be, and there are no straightforward mechanisms to identify and develop them. With any proposed technology innovation, one must gamble that it will be compelling enough to attract a community of early adopters; otherwise it will probably not succeed in the long run. This chicken-and-egg-type problem proved a significant challenge in the Active Networks program (as did failure to build a sufficiently large initial user community from which a killer application could arise).
There is a tension between experimentation on a smaller scale, where the environment is cleaner, research is more manageable, and the results more readily interpreted, and experimentation on a very large scale, where the complexity and messiness of the situation may make research difficult. A particular challenge in networking is that many of the toughest, most important problems that one would look to a disruptive networking technology to solve have to do with scaling, so it is often important to push things to as large a scale as possible. One-of-a-kind prototypes or even small testbed networks simply do not provide a realistic environment in which to explore whether a new networking idea really addresses scale challenges.
This suggests that if the research community is to attract enough people with new application ideas that need the disruptive technology, there will be a need for missionary work and/or compelling incentives for potential users. Natural candidates are those trying to do something important that is believed to be very hard to do on the Internet. One would be trustworthy voting for public elections; another, similar candidate would be developing a network that is robust and secure enough to permit organizations to use the public network for applications that they now feel comfortable running only on their own private intranets.
While focused on the disruptive ideas that could emerge from within the networking research community, workshop participants also noted the potential impact of external forces and suggested that networking (like any area of computer science) should watch neighboring fields and try to assess where disruptions might cause a sudden shift in current practice. The Internet is certainly subject to the possibility of disruptive events from a number of quarters, and many networking researchers track developments in related fields. Will network infrastructure technologies—such as high-speed fiber or wireless links—be such a disruption? Or will new applications, such as video distribution, prove a disruptive force? Workshop participants did not explore these forces in detail but suggested that an ongoing dialogue within the networking research community about their implications would be helpful.