A Method for Applying LOTOS at an Early Design Stage and Its Application to the ISO Transport Protocol

We propose a method applicable to the design of large and abstract LOTOS specifications. More precisely, this method explains how to generate a constrain-oriented specification which is an adequate abstract and modular starting point of a complex design process leading to implementation. It is illustrated on a substantial part of the ISO Transport Protocol class 4 which is considered as a complex and stable case study. Having proved the feasibility of the method on this protocol, it was then used to specify (parts of) the new transport protocol TPX of OSI95.