Abstract :
Complex protocols are used to coordinate remote activities in computer networks. To insure proper operation, formal techniques of protocol definition and validation have been proposed, and developed to the point that they can be applied to actual protocols. However, much work remains to be done in order to cope with protocols of ever-increasing complexity; in particular, those coordinating the activities of many interacting entities. The characteristics that determine the applicability of the different specification and validation techniques to a protocol will be discussed. We will define the "topology" of a protocol, and treat also protocols that are intended to work in a variety of configurations, as well as configurations which may change in time (i.e. "evolving topologies"). Finally, based on this new general point of view, a short survey of specification and validation techniques will be presented, and the extensions needed to handle complex protocol characteristics will be discussed.
