Research And Design Of A Composite Web Service Reliability Analysis Tool Based On Simulation

Along with the standardization of Web services composition language and the widespread acceptance of composition technologies, Web services composition is becoming an efficient and cost-effective way to develop the modern business applications. Web services’ application fields are growing very generally, have been gradually penetrate into the banking system, military command systems, aviation management systems, etc. So no matter the system Web services or application of Web services must have a high reliability. Once appear faults, it will cause irrparable damage. As Web services are implement by different providers, they are isomerism and indeterminate. The traditional approaches for software reliability evaluation cannot be used. Simultaneously, more and more fault tolerant mechanisms are applied in Web services composition, which is improved the reliability of Web services composition. The evaluation of Web services composition is not accurate without considering of the fault tolerant mechanism effects.Aimed at the current state of composite Web services’ reliability research, this research first analysis the Web service composite language standard Business process execution language(BPEL), and then the BPEL is transformed to a simple reliability evaluation–oriented of the Web services composition dependency tree(FTWS-CDT) is derived by some mapping rules and composite arithmetic. WS-CDT can made the expression of composite Web services more simple and can present more complex structures. Next the reliability process of the component service and services connection undergo the various fault manage strategies of the fault tolerant mechanism are analyzed. Based on WS-CDT, the reliability of Web service compositions is evaluated and the sensitivity analysis of component service and connectors by using the simulation approach. Also, we will recommend best fault-tolerant strategy for the user.At the end, experiments are shown to present this tool can predict the reliability of the composite Web services accurately and rapidly. Use this tool, we can analyze how the services connection and the operational profile influence on the system. At the same time realize the service component reliability sensitivity analysis, find the key service. The reliability analysis tools can provide service designers consider fault-tolerant mechanism of Web service composition method of reliability evaluation and it will be a new way to prediction, explore the Web service reliability analysis.