George Prezerakos

Demand for value added services creates significant revenue opportunities for operators that decide to open their networks to external service providers. This process is practically feasible only if standardized interfaces to core network operations are utilized. This way the cost and complexity of the development and integration process is reduced, as well as the service administration overhead, which is distributed

Intelligent Network is one of the most successful communication concepts world-wide. The survival of this concept into the next century largely depends on the deployment of interactive multimedia services which in turn must be supported by an adequate network infrastructure. In this paper a staged service specification and development philosophy is proposed which blends a multimedia oriented IN service architecture with B-ISDN transport capabilities. The outstanding feature regarding this approach is that, while it originates from the existing narrowband single media reality, it additionally provides detailed evolutionary steps towards future services running over the emerging high speed public networks. An enhanced IN/B-ISDN architecture is used as the starting point for the provision of core multimedia characteristics such as call/connection separation and co-ordination of multiple calls within a session. Consequently, the way by which the service prose description can serve as a means for the decomposition of a multimedia service into discrete functional stages is presented. The available options regarding the distribution of the identified functionality among the IN network nodes are examined next, followed by the definition of service specific information flows across the various interfaces. The results from this specification work are used for the production of a formal service description in SDL. This description is mapped to a library of object oriented service building blocks utilised by a service creation environment for the production of the actual service logic program. Selected parts of new multimedia services (Video on Demand) as well as existing multimedia services, originally targeted at TCP/IP environments (Video Conference), are presented in order to demonstrate an implementation viewpoint with respect to the proposed methodology. Finally, the advantages of the specification and design approach discussed in this paper are justified through comparison to other existing approaches in the same field.

The paper targets the specification process of context- aware end-user services targeted at mobile systems beyond 3G based on two key concepts. A personalization device that enables services to adapt to a variety of terminals, networks and user preferences and a distributed brokerage framework that orchestrates service related resources by implementing adaptive policies for inter-broker message exchange. Both concepts are