Intelligence on top of the networks: SIP based service control layer signaling

In order to support the integration of heterogeneous networks and diverse access devices, we have developed a server architecture that provides integrated telecommunications and data services spanning heterogeneous networks. The server architecture interfaces to the networks via adaptation units to provide a network independent service control on top of the networks. We have structured the architecture according to the principles of the TINA service architecture in a user control part, a service control part and a communication control part. We have adopted the IETF session initiation protocol (SIP) to serve as a service control layer signaling protocol. Our session control protocol (SesCP) supports the setup and control of complex multimedia communication services and provides flexibility in order to support a wide range of new services. In particular, SesCP provides signaling mechanisms that support different levels of the service description, starting with the service called `called-by-name´ and finally coming to a precise connection description that is realized in the networks. SesCP also supports the negotiation of service description parameters