Dynamic Selection Of Redundant Web Services

In the domain of Web Services it is not uncommon to§find redundant services that provide functionalities§to the clients. Services with the same functionality§can be clustered into a group of redundant services.§Respectively, if a service offers different§functionalities, it belongs to more than one group.§Having various Web Services that are able to handle§the client s request suggests the necessity of a§mechanism that selects the most appropriate Web§Service at a given moment of time.§§This book presents an approach, Virtual Web Services§Layer, for dynamic service selection based on§virtualization on the server side. It helps managing§redundant services in a transparent manner as well as§allows adding services to the system at run-time. In§addition, the layer assures a level of security since§the clients do not have direct access to the Web§Services. §§Several selection techniques are applied to increase§the performance of the system in terms of§load-balancing, dependability, or execution time. The§results show which techniques are appropriate when§various QoS criteria of the services are known and§how the correctness of this information influences on§the decision-making process.