IMCReo: interactive Markov chains for Stochastic Reo

The study of composed software and its properties is in itself a great challenge. Bringing quantitative aspects into the picture increases the complexity of the analysis and entails the need for reconciling both the classical and the stochastic analyses. The quest herein is to provide constructs for composition of building blocks and semantic models thereof which enable both analyses and allow for modeling and verification. Stochastic Reo offers constructs for component and service coordination and provides means for specification of stochastic values for software connectors. Interactive Markov chains (IMC) on the other hand, are a stochastic, compositional, extension of classical models of concurrency, integrating classical and stochastic aspects. This paper discusses how IMC can be effectively used as a compositional semantic model for Stochastic Reo, avoiding to resort to a separate automaton model, often lacking full compositionality, as intermediate semantics. A tool chain integrating available tool support for IMC, is described and applied in the analysis of a case study dealing with performance and resource allocation of a mediation system.