Ontology-Based QoS Queuing Model for Selection of Web Services Servers

Finding an appropriate Web service is the best chance due to lack of semantics in the protocols used to specify and publish them. UDDI and WSDL do not provide grounds to find appropriate web services at the required accuracy and Quality of Service (QoS). This article discusses a Semantic Search Agent (SSA) approach that discovers appropriate web services according to their semantic description. QoS requirements and input/output information of the fetched Web services are compared against client requirements. A QoS broker-based scheme is considered as basis of a broker/dispatcher model which incorporates a multi-class queuing model. We augmented the model with semantic technologies, discussed implementation, and exemplified its use. Performance of the system in terms of throughput and response times was analyzed and simulated. Both set of values for a sample system configuration was found almost identical, also identifying request levels causing saturation.