Conformance Testing of Complex Services Exemplified with the IMS' Presence Service

Testing of network elements on conformance to their respective protocol specification has become a common phase during the development process. For this purpose, special programming languages, such as TTCN-3, as well as tools are available. In the context of testing complex communication architectures on conformity, further difficulties were revealed. When testing hybrid network elements with multiple interfaces and different protocols, new testing methods are needed. Systems under test have to be stimulated on all interfaces with emulated network elements, which have to be controlled and synchronised. This paper considers the requirements, design, implementation and application of testing methods for complex communication architectures. We developed an executable set of test cases for IP Multimedia Subsystem's Presence Service, as prominent example for a complex communication architecture. It is our plan to use these developed test cases as an input for ETSI's work on the conformance and interoperability standardisation process for IMS. This paper is based on a current research project funded by the government of Lower Saxony within the AGIP Programme and a co-operation with the University of Glamorgan, Wales and Testing Technologies IST, Berlin as commercial partner.