AN INTRODUCTION TO ET-LOTOS FOR THE DESCRIPTION OF TIME-SENSITIVE SYSTEMS

Enhanced Timed-LOTOS, called ET-LOTOS, is an extension of LOTOS allowi ng the modelling of time-sensitive systems (i.e. systems whose behavio ur is influenced by the passing of time). It is the basis of the timed extension of LOTOS currently developed by ISO (1995). The purpose of this paper is to present ET-LOTOS in a tutorial style and show its app licability. The detailed study of the formal semantics is addressed in another paper. A collection of small but realistic, examples illustra tes a wide variety of time-sensitive protocol mechanisms. These exampl es are used to introduce and justify the extensions of our language. F inally, the basics of the formal semantics are given and a comparison is made with other timed formalisms.