quality of communication-based systems presents the research results of students of the graduiertenkolleg `communication-based systems to an international community. to stimulate the scientific discussion, renowned experts have been invited to give their views on the research areas: formal specification and mathematical foundations of distributed systems using process algebra, graph transformations, process calculi and temporal logics performance evaluation, dependability modelling and analysis of real-time systems with different kinds of timed petri-nets specification and analysis of communication protocols reliability, security and dependability in distributed systems object orientation in distributed systems architecture software development and concepts for distributed applications computer network architecture and management language concepts for distributed systems.