Web Services-based Middleware for QoS Brokering of Media Content Delivery Services

Powerful computers and affordable digital media ap- pliances result in a rapid growth of possibilities in the field of multimedia applications. There has been a significant increase in creation and use of multimedia content. Nowadays everybody can be treated as a potential creator and user of multimedia content. In order to deliver multimedia services to end-users, many parties are integrated and a series of Web services is accessed. A Web service in the composition can become unreachable by a number of circumstances, which requires run-time actions to replace it by another compatible Web service. A Web service can also perform less well than guaranteed, which also requires action in order to fulfill QoS requirements. To answer these requirements, we designed a broker middleware offering dynamic selection and composition of Multimedia Content Delivery services and automatic load balancing of these services over the available application servers. Since users want fast and reliable connections and they do not really care what is happening in the background, the broker platform transposes all services in a transparent and similar fashion, hiding for the users if it concerns a simple or composed service and thus simplifying required user interactions. The broker architecture intercepts all service requests and makes sure those requests are redirected to the best provider server, even in the case of composed services. The architecture will also allow the automatic fulfillment of QoS requirements, such as response time, availability, quality and price.