Design and Verification of Distributed Multi-media Systems

Performance analysis of computing systems, in particular distributed computing systems, is a complex process. Analysing the complex flows and interactions between multiple threads over a distributed set of processing nodes is a non-trivial task. The problem is exacerbated by the addition of continuous system functions that are time dependent, such as communication between components in the form of multimedia streams of video and audio data. Quality-of-Service (QoS) specifications define constraints on such communications and describe the required patterns of data transfer. By making use of these specifications as part of the performance analysis process it is possible to add significant confidence to predictions about the correct (required) operation of a distributed system. This paper presents a method for designing distributed multimedia systems, including the specification of QoS, using the ODP framework and UML and describes a technique for verifying the QoS specification against the designed functional behaviour of the system using Timed Automata.