Design and implementation of a converged open messaging architecture for next generation networks

This thesis presents a research project on multi-channel messaging for Next Generation Networks (NGNs), covering miscellaneous aspects of convergence. It describes an architecture on top of an IP Multimedia Subsystem (IMS) for implementing an Instant Messaging (IM) service based on the Session Initiation Protocol (SIP) that allows an easy and straightforward integration of various heterogeneous messaging protocols to deliver continuity of service with legacy networks. The Internet Engineering Task Force (IETF) introduced "SIP for Instant Messaging and Presence Leveraging Extensions" (SIMPLE) as a protocol suite that constitutes an open and interoperable standard for instant messaging and presence. Relying on this set of specifications, the Open Mobile Alliance (OMA) has developed an application enabler (SIMPLE IM) that defines a complete architecture and framework in order to enable interactive communication capabilities over an IP-based infrastructure. OMA Converged IP Messaging (CPM) specifies the successor enabler which provides a transparent and seamless approach of interworking between disparate messaging services in the Telecommunications and Internet domain while leveraging standardized functionalities from existing enablers. The drafted framework of CPM has been the fundamental design pattern for the system layout realized within this work. For this thesis developed, the converged messaging architecture extends the previous mentioned SIMPLE IM enabler with several components. Interworking Functions (IWFs) represent the protocol adaption logic between SIP and the specific messaging protocol whereas an Interworking Selection Function (ISF) is responsible for delivering the messages towards the appropriate IWF. In addition, an Application Control Function (ACF) will be introduced which exposes the messaging features to external functional components like Value-Added Service (VAS) applications. Furthermore, this thesis outlines the integration into a NGN infrastructure and the benefits and open issues arising from this concept. A broad overview of the specification and standardization landscape is given as well as the interconnection between existing and ongoing standards that are relevant for this research topic. In addition to basic considerations it is intended to also deal with the practical prerequisites which inform the system design. As a p roof-of-concept, the Converged Open Messaging Server (COMS) has been developed, implementing the designed architecture. COMS is integrated and validated on the Open SOA Telco playground provided by Fraunhofer Institute FOKUS. The paradigm demonstrates the feasibilities in multiple use case scenarios including messaging convergence and the interaction with other telecommunications enablers and messaging protocols, just as innovative context-aware approaches which enable the users to experience a variety of personalized services seamlessly across different platforms and technologies.