A Web Service Communication Policy for Describing Non-standard Application Requirements

Web services are not really suitable for implementing applications with non-standard communication requirements, such as e.g. applications with data streaming and/or realtime requirements, applications depending on the transfer of large files, and legacy applications with complex message exchange patterns. This paper presents a communication policy for Web services based on WS-Policy, which enables the description of real-time and data streaming requirements, of file transfers, and of protocols and clients used by legacy applications. It is used in addition to the WSDL description of a service, and thus complements the service description by exposing the protocols used by the applications for the various requirements. By investigating a video-on-demand application, several limits of Web service technologies and the benefits of using the communication policy to describe such requirements are illustrated.