Uncovering ISO ROSE protocol errors using Estelle

One of the main objectives of ISO in developing FDTs is that protocol specified in them can be verified. However, standardized FDTs have been designed largely for specification purpose; success of using them for protocol verification has been rarely reported. We have developed a technique of translating Estelle specifications into Numerical Petri nets, which can then be verified by a proven automated verification tool, PROTEAN. The merits of our approach are that specifications are fully based on standard Estelle, and dynamic behaviours of an Estelle specification can be handled. In this paper, we present a success story of using Estelle and the techniques we have developed to uncover ISO ROSE protocol errors. We find that Estelle is an FDT capable of analysing and verifying real protocols and it is therefore important to the development of ISO protocol standards.