Software architecture of an X.400 electronic mail system

Abstract

This paper describes the development of a prototype electronic mail system. An outline of the systems' architecture is followed by an account of design process. Special attention is given to a number of aspects (services) that are not part of the CCITT X.400 recommendations, such as online configuration management, system recovery, message recovery and reliability. Important characteristics of the architecture are described, including its modularity, flexibility and the ability to interface to non-OSI networks and services.