Object-oriented design of a message handling system protocol

This paper presents a specification and object-oriented modelling technique for a distributed application. The object-oriented specification of a distributed application provides a natural mapping of the system components onto objects and supports the implementation of reusable software components. The application is the X.400 message handling system defined in its 1988 version in the context of the reference model for open systems interconnection. The BOOCH object-oriented analysis and design method has been used to facilitate the mastery of the notation and the process of object-oriented design by understanding the fundamental elements of the object model such as abstraction, encapsulation, modularity, hierarchy, typing, concurrency and persistence