A Flexible and Dynamic Failure Recovery Mechanism for Composite Web Services Using Subset Replacement

Today businesses are very complicated and intricate and they provide a variety of services; these huge numbers of services cannot be provided by an individual web service and hence we require a collection of web services which can deal with these complex services. In this paper a mediator (broker) is developed who will make the interaction between service providers and service requesters more intelligible. Execution of composite web services deals with execution of all the individual web services. Hence, it is very likely that the composite web services are liable to failure than their individual or atomic counterparts. At the time of execution of these composed web services, even if an individual service fails or becomes inapproachable, it results in non-function of the entire composed web services. In this situation of total non-function the entire process is to be re- executed. Therefore, for this purpose we require a mechanism to ensure that the web services which have failed are replaced rapidly and effectually for smooth functioning of the whole business. The thesis is thus aimed at developing a dynamic fault tolerance mechanism which will replace the subset containing failed web services with QoS based equivalent subset. This thesis will thus have the ability to reconfigure the failed web services at runtime and recover them from failure.