Active Networking Means Evolution (or Enhanced Extensibility Required)

A primary goal of active networking is to increase the pace of network evolution. Evolution is typically achieved via extensibility; that is, typical active network implementations provide an interface to extend network nodes withdyna mically loaded code. Most implementations employ plug-in extensibility, a technique for loading code characterized by a concrete, pre-defined abstraction of future change. While flexible and convenient, we argue that plug-in extensibility alone is not sufficient for true network evolution. Instead, we propose dynamic software updating, a technique that reduces the a priori assumptions of plug-in extensibility, improving flexibility and eliminating the need to pre-plan extensions. However, this additional flexibility creates issues involving validity and security. We discuss these issues, and describe the state-of-the-art in systems that support dynamic software updating, thus framing the problem for researchers developing next-generation active networks.