Development of complex communications protocols using Estelle

During the decade that has elapsed since its standardization by ISO, the Estelle formal description technique has been successfully applied to the development of various communications protocols. We present in this paper a protocol engineering methodology that has resulted from the use of Estelle in several projects, involving the specification, validation, performance analysis and implementation of real-life, complex protocols. The methodology is based on the support offered by the Estelle development toolset (EDT). It gradually evolved, in parallel with the continuous enhancement of EDT, aiming to provide a protocol engineering environment that consistently supports the entire development process. We outline in the paper the principles of the methods and illustrate them with examples of their application to the development of an innovative transport protocol with multicast and multimedia capabilities.