Assessing the scalability of component-based frameworks: the CADENUS case study

This paper proposes an approach to scalability analysis of component-based systems. A theoretical model of the orchestrated behavior of a system's components is developed and potential bottlenecks are identified. The model is derived by performing an analysis of the average number of messages that each involved entity has to deal with, i.e. receive, elaborate and possibly forward. By appropriately setting the various model parameters, it is possible to evaluate a system's behavior in a number of different scenarios. The model itself is based upon a queuing network paradigm, whereby each component is associated with a "service centre" characterized by specific values of both the message arrival rate and the service time: based on such values, the utilization coefficient of the service centers is computed and the potential bottlenecks are identified. The queuing network model is also exploited to evaluate the performance of the overall system under various configurations. The proposed approach is introduced and developed by taking the CADENUS system as a running example. CADENUS is a component-based framework designed and developed within a recent IST project, whose main goal resides in the provisioning of Premium IP services by means of an effective application of the so-called mediation paradigm.