Design of a Contract-Based Web Services QoS Management System

A QoS (Quality of Service) contract is an agreement between the web service provider and the web service user that specifies the level of service quality. Web service users can be assured of the level of the service quality specified by the QoS contract. A quality management system is used to enforce QoS contracts.The QoS management system supports various management functions such as the creation and deployment of the QoS contract, registration of web services, conformance monitoring to see if the service quality provided conforms to the contract, and notification of contract violation. We propose a QoS management system architecture for the contract-based web service in this work. Under this architecture, the management system utilizes agents to monitor the web services quality and manages the service quality by notifying the service provider and user of the service contract violation. Furthermore web service users can see QoS information by contacting the QoS server of the system.