 Enablers are the main tools for the service network, creating value beyond voice. Semantically, also the often-used term 'middleware' has a flavour of enabler, by offering API, service handling and end-to-end protocols (e.g. XML) to the applications. The service layer can also be regarded as a promoter of business contacts via telecom on behalf of direct contacts or contacts via other media. It participates in the contacts as an enhancing middleman. Many presentations do not show the traffic flow between the server in the service network and the client. Such flow has been included in the reference model, and also a hint regarding the interaction between service network and terminals. In fact, there are strong dependencies between the terminals and the service network, creating needs of combined application development. Figure 9.3 gives an example of the server-rich structure of the service network and also the traffic flow referred to above. Understanding Changing Telecommunications - Building a Successful Telecom Business Content & application Telecom business provider Operations Back-end Content = $$ systems User support Application support Business support General Application Management Authentication, (CAS) framework support authorization Provisioning, Common billing, SCS, service enablers directory CRM, etc. Provisioning center Enablers Deployment Operation and Maintenance CAS = Customer administration Acc. and billing Location Presence Messaging Application Etc. system proxy General framework, middleware Figure 9.4 The spider role of the service network based on an OMA structure Whereas Chapter 8 primarily is a technique integrator in this book, Chapter 9 is an overall integrator. Chapters 2 and 4 become especially important now because of the spider role of the service layer and its main component, the service network. As mentioned before, the service network is a product of the converging telecom, datacom and media industries. The first stage was the functions of the ISP, as the tele- com intermediary be