The design of complex and reliable IT systems is a challenging engineering problem. In contrast to traditional engineering disciplines, predictability cannot be guaranteed at design time and a posteriori analyses are mandatory for ensuring correctness and estimating runtime performances. This report presents a system design methodology based on BIP - Behaviour, Interaction, Priority - component framework. BIP is a component model providing strict separation between behaviour of components and their coordination, an enhanced expressiveness for encompassing heterogeneous execution and interaction and finally, a rigorous operational semantics and a general execution model. The BIP design methodology represents a first significant step towards constructive and predictable system design. It favors a correct-by-construction design process, formalized as a sequence of semantics preserving model transformations, which lead progressively from a model of the application software to an implementation by taking into account execution platform constraints.