Although the interoperability among systems can be achieved through the use of well-de ned interfaces to services, communication between the blocks of SOA needs to be done so that at least some form of quality of service may be offered to the client of the service, be that a Web client, another service or a set of services. The architecture model proposed in this book should enable better provision of quality of service among the messages exchanged among applications. The main focus of the WSARCH, which makes it different from other architectures, is the fact that it is an architecture...