A simulation model supporting time and non-time metrics for web service composition

A next generation network (NGN) exploits advanced multiple broadband, quality of service (QoS)-enabled service technologies. The NGN is aimed at users and service-related functions, including web services. Recently, web service composition (WSC) has become a new approach for overcoming many difficult problems confronted by B2B e-commerce, inter-organization workflow management, enterprise application integration etc. Due to the uncertainty of the NGNs and various web services, the performance of the WSC cannot be ensured. How to model it and predict its performance becomes a difficult problem for WSC. In this paper, we propose a novel performance simulation model for WSC, called STPM ⁺. The STPM⁺ model can support modeling and simulating the time and non-time QoS metrics. Based on the stochastic timed colored Petri net, the STPM⁺ model can simulate and predict multiple QoS metrics, such as cost, reliability, reputation and so on. To examine the validation of our STPM⁺ model, we have designed and realized a visual performance simulation tool, called VisualWSCPE. Based on VisualWSCPE, we have fulfilled some simulation experiments. The experiment results demonstrate the feasibility and efficiency of the STPM⁺ model.