Protocol Tracing

Tools for performing automated analyses of data communication protocols are frequently based on symbolic execution algorithms that search the behavior of finite state machine models. The symbolic execution algorithms, however, are inherently restricted in the size of the models that they can handle. They work well for models that generate up to 100,000 system states. Beyond that the time and space complexity problems prevent effective analyses. A simple model, that would lend itself to faster symbolic execution, is often too restrictive for adequate modeling of real life problems. Extending the model to include, for instance, variables and value passing expands the state space to be searched by orders of magnitude, far beyond the scope of an unmodified symbolic execution algorithm. We will discuss an experimental protocol tracer that specifically aims to battle the complexity of larger protocols. Computer Networks and Simulation, Vol III, North Holland Publ. Co. 1986