Component-Based Software Engineering is quickly becoming a mainstream approach to software development. At the same time, there is a massive shift from desktop applications to embedded communicating systems (e.g. PDAs or smartphones): it is especially the case for multimedia applications such as video players, music players, etc. Moreover, embedded communicating systems have to deal with open aspect: applications may come or leave the system on the fly. A key point of these systems is its ability to rigorously manage Quality of Service due to resource constraints.