On measuring the complexity of an estelle specification

Software metrics are useful quantitative indicators to assess and predict software quality attributes; a commonly measured attribute is software complexity. The main drawbacks of these metrics are: they can only be calculated after a major development effort has been committed to producing the source codes; they cannot provide early feedback during the specification phase; and subsequently it is expensive to make changes to the system, if so indicated by the metrics. Formal Description Techniques (FDTs) enable formal specification to be systematically analyzed. They should also make it possible to assess software quality attributes like maintainability and reliability, and to predict the development or maintenance cost/effort early in the specification phase of the formal protocol development life cycle. To date, little work has been devoted to this area. In this paper, we describe how the complexity of an Estelle specification can be measured. The Sliding Window Protocol specified in Estelle is used as an example to illustrate our approach to measuring the complexity of an Estelle specification. The Management Decision Support System (MDSS), which integrates software measurement into the formal protocol development, is also described in this paper.