Evaluating QoS parameters for ranking Web service

With the increasing number of functionally similar web services available on Web, the trustworthiness of published QoS information and reputation for Web service discovery for simple or complex task has been a challenging issue for the practitioners. The QoS includes a number of non-functional parameters such as price, response time, availability, reliability and reputation. The QoS of composite service can be achieved by fair computation of QoS of every component service invoked. Invoking a low quality component service can slow down the overall performance of the composition. Most of the existing approaches do not consider the broker´s rating during monitoring of Web service. In this paper, a QoS evaluation and monitoring mechanism with some new QoS parameters Access Rate and Overall Aggregated Effective Quality of Service (OAEQoS) are proposed. The evaluation of proposed parameters is performed at the trusted third party broker´s operating environment during new service registration to assure the quality of service. The broker can assign rank from the value of OAEQoS parameter. With the help of proposed parameters, the broker publishes the services with their overall quality score that can help service consumer to retrieve best services.