Quality of Service Engineering deals with the management and control of dis­ tributed applications coping with multiple media. Controlling concludes the discriminating of qualities obtained and qualities specified. Thus, this-is a kind of verification. Since qualities describe how things have to be done, the verifi­ cation of qualities depend on the running environment. Conformance between a specification and its realization is· necessary but not sufficient. In the OSI framework conformance verification methodologies - by testing - have almost maturely been developed. Quality verification methodologies - by controlling - are lacking. Thus, we have to investigate into the requirements of the new mul­ timedia and high speed communication technology. These technologies are the means by which new systems and services will be built. The actual verification of the Quality of Service (QoS) depends from the embedding system and thus can only be checked during system operation time. In order to understand and to identify verification mechanisms and architectural observation or control points, a generic QoS model is enyisaged. The new model is based on the basic concept of continuity respectively of processes in order to model continuous behaviour, i.e. streams adequately.
['Jan de Meer', 'Son T. Vuong']
The Challenge of QoS Verification