Quality-of-Service Testing - Specifying Functional QoS Testing Requirements by using Message Sequence Charts and TTCN

With the upcoming use of multimedia systems, quality-of-service (QoS) architectures and QoS testing have become a research topic. QoS testing refers to assessing the behavior of a system performing monitoring of negotiated QoS parameter values. QoS testing extends OSI conformance testing since non-functional properties have to be tested, too. We identify requirements for a QoS test specification language and evaluate existing languages against these requirements. We propose the combined use of TTCN (Tree and Tabular Combined Notation) and MSC (Message Sequence Chart) for specifying functional QoS testing requirements. In our approach we use MSC for a high-level overview of the test system components and their respective interactions that are defined in a TTCN test suite. For specifying non-functional requirements, e.g., time constraints, we elaborate on a real-time version of TTCN.