Scalable federated broker management for selection of web services
Standard specifications of Web Services are mainly concerned with Web Service publishing and discovery. However, there is no standard regarding Web Service selection, which is very crucial for providers and clients. It will support clients in selecting Web Services based on required Quality of Web Service (QoWS) and support providers to remain competitive. Most of solutions on Web Service selection are very often based on a central component to make the selection decision, do not scale to the growing number of clients and Web Service providers, and/or lack trustworthiness. The objective of our approach is to support clients in selecting, and monitoring appropriate Web Services while increasing scalability, trust and reliability of Web Service selection. We propose a framework based on a federation of cooperative brokers. Each broker in the federation manages Web Services within its domain of expertise, and cooperates with its peers to select appropriate Web Services. We describe the federation management operations and our cooperative brokers QoS-aware selection algorithm. We propose certification and monitoring of Web Services as well as monitoring of brokers. The implementation and the experiments we have conducted evaluated the performance of our approach. The obtained results show that: the load is shared and distributed among brokers, a large number of client requests with different QoWS requirements were served, the architecture can scale up in order to include other brokers and/or other Web Services, and selection is guaranteed, trustworthy as it is supported by monitoring.