Quality of Service in Networks and Distributed Systems

Distributed multimedia systems are becoming more and more important in many situations of our daily life, for instance in office applications (video conferencing), learning environments (tele-teaching and tele-learning, virtual universities), or entertainment (online games, video-on-demand). Usually, some of the media types used in such an application have specific requirements on their transmission and presentation. The notion of Quality of Service (QoS) plays a central role when discussing about how to fulfil these requirements of multimedia applications. Distributed multimedia systems need QoS support in order to function properly. Moreover, other applications such as certain simulation systems need QoS functionality as well. For this reason, research in QoS has increased significantly during the past few years. For an end-to-end QoS, which is in most applications necessary (user to user), support has to be provided in all components of the participating systems, i.e., the end system components, the communication system and the application. Accordingly, there has been active QoS research in network hardware (switches, routers), protocol software (RSVP, RTP etc.), operating systems (CPU scheduling), user interfaces, etc. Today, some of the basic technical issues are understood, but a significant amount of work is still necessary. Furthermore, additional research is devoted to (partially) non-technical issues such as pricing for QoS, but also new technical developments such as Active Networks. This seminar concentrated on these new issues. In 30 talks and a number of panel discussions, the following topics were covered: QoS Architectures/QoS Management, Integrated and Differentiated Services, Multicast and Routing Issues for QoS, QoS in Mobile and Wireless Environments, Pricing and Accounting for QoS, QoS in Heterogeneous Networks, Active/Programmable Networks and QoS, QoS in Middleware, User Level QoS, and Adaptive Applications. This report gives an outline of all talks and thus provides a good overview of the current state of the art in QoS research.