Yuhui Chen; Romanovsky, A.; IT Professional Volume 10, Issue 3, May-June 2008 Page(s): Digital Object Identifier /MITP Improving the Dependability of Web Services Integration Reporter: 廖宇祥 Date:

Outline Introduction Web Services Dependability WS-Mediator Approach WS-Mediator Framework Evaluation Conclusion 2

Introduction This paper propose an approach to improve the dependability of Web services integration. Using an off-the-shelf mediator architecture to support resilience-explicit dynamic Web services integration. 3

Web Service Web services offer advantages over conventional distributed computing middleware platforms. Implement capabilities and functionalities via computer networks, especially the Web. 4

Web Service cont. XML SOAP WSDL UDDI 5

Web Services Dependability Some of those services are dynamically discovered via UDDI. Research on the topic typically focuses on ensuring these services’ dependability and the communication between clients and service providers. 6

WS-Mediator Approach 7

WS-Mediator General Architecture 8 The WS-Mediator is an architectural solution deployed on a distributed infrastructure between a set of clients and Web services that they access. In Web services, the distinction between a client and a service provider is blurry.

WS-Mediator General Architecture 9 Dynamic Reconfiguration The dynamicreconfiguration component is handling service-execution procedures. The faulttolerance mechanisms fault-tolerance techniques, which can vary when adapted to particular application scenarios.

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Service Policies 11 When a client invokes the submediator, three kinds of information are assembled in the SOAP message embedded SOAP messages an execution policy a global-execution policy

Resilience-Explicit Computing 12 It’s a critical concept in the WS-Mediator approach. The resilience metadata generated by the monitoring mechanism is used for resilience-explicit dynamic reconfiguration.

WS-Mediator Framework 13 Implemented a Java prototype of the WS-Mediator to validate the approach’s applicability. Consists of the remote submediator and Mediator-Elite components.

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Evaluation 15 deployed a Java WS-Mediator framework on three Blast Web services: EBI VBI DDBJ

Evaluation cont. 16 The recovery block execution mode

Evaluation cont. 17 the N-version programming execution mode

Conclusion 18 The evaluation experiments have demonstrated the potential of our WS-Mediator system. modeling a detailed overall architecture of the WS- Mediator system and its components. We envision deploying a general WS-Mediator system for public access and evaluation as well as integrating the WS-Mediator system into a real-world e-Science application.

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