Despite progress in model engineering, modeling large distributed systems is still a long and complex task. This paper outlines a methodology based on UML to make the modeling of a set of related systems simpler. A generic component-based framework specifies the commonality and variability of these systems at high-level of abstraction both from structural and behavioral viewpoint. Then, models of specific systems are derived from the coarse-grained generic framework. A case study in the field of QoS management systems illustrates this approach.