stems will be developed as a 'federation' of services at the point of execution. When it becomes possible to utilize services to create new ones the power of networking will be fully exploited. This will enable alternative software components to be substituted between each use of a system. Understanding Changing Telecommunications - Building a Successful Telecom Business Business processes, customer applications Authentication Payment Evolving standards Authorization Transactions Web service Proprietary Existing standards below solutions part of service layer, in this Publication and discovery - UDDI context Service description - WSDL Messaging - SOAP transport-HTTP, FTP, SMTP IP networks Figure 3.46 Web services standardization Web services perform functions, which can be anything from simple requests to compli- cated business processes. Once a web service is deployed and published, other applications (and other web services) can discover and invoke the deployed service. The main web ser- vice area in the context of this book is shown in Figure 3.46. Clearly, it is positioned close to service enablers and middleware. This makes the area above IP a dynamic one, indeed. Examples of component services that are reusable building blocks are currency con- version, language translation, shipping and claims processing. The new era can be called 'software as a service', using service-oriented programming (SOP). SOP is a paradigm for distributed computing that supplements object oriented pro- gramming (OOP). Whereas OOP focuses on what things are and how they are constructed, SOP focuses on what things can do. The way to work is roughly like this (for web services): The developer - Create application logic, generate a service description and register it in the publication and discovery library. The user - Call the service from the discovery library. The software is then transported as a simple XML-based protocol to let applications exchange information over HTTP. Insert the application logic into a process flow. To boost 