Formal description techniques

Early in the development of OSI, it was recognized that formal description techniques (FDT´s) would be required to accomplish the goals of OSI. This paper is a brief history and a report on the status of the work of ISO/TC97/SC16/WG1 ad hoc Group on Formal Description Techniques. The group comprises three subgroups: the first working on architectural concepts; the second, on an FDT based on extended finite-state machines; and the third, on an FDT based on temporal ordering of interaction primitives. An overview of the techniques developed by each of these groups, as of December, 1982, is presented.