Nowadays, communication systems based on Internet Protocol (IP) are spread in a wide range of applications. Thereby, conventional communication systems are replaced by VoIP (Voice of over Internet Protocol) solutions. A further trend deals with the integration of new with already existing services into a uniform infrastructure based on the paradigm and discipline of a service-oriented architecture (SOA).

This diploma thesis deals with studying different solutions for integrating a VoIP service in the scenario mentioned above. Based on the findings and results, a reference implementation has to be realized.