Coordination of multimedia services and applications in mobile, heterogeneous network environment

The Internet architecture is flourishing through its ability to provide broad variety of electronic services like electronic messaging, telephony, or audio/video conferencing and on demand services. Multiple services display common characteristics, especially in cases of coding of audio and video media, in order to cover the requirements of different users (consumers and providers of media contents) and of various access-network technologies. Micro/macro IP mobility and wireless IP technologies pave the way towards the integration of today’s Internet with the next generations of mobile telephone systems into All-IP communication architecture. In order to achieve harmonization, future generations of networks and services need to address the increasingly important challenges of cross bridging of networks, wireless access, mobility management, Quality of Service (QoS) provisioning for different kinds of applications and multimedia-supporting services. Current protocols and mechanisms for providing QoS cover predominantly single facets of the global QoS management. However, QoS is a system aspect that crosses all components and layers of a distributed multimedia system. Consequently, the control mechanisms for service management turn to be increasingly complex with the growing system heterogeneity and the service users and providers should be prepared to dynamically exchange and evaluate possible system configurations in different network environments and scenario situations. The complexity of the system configuration however shall not be delegated to the human users as the average user of multimedia applications lacks the knowledge to perform such configurations or is unwilling to spend the time for manual system adjustments. Furthermore, network and service providers wish to have possibly exact management of the services which can be guaranteed only having suitable automatic controls. Hence, automatic negotiations of system configurations and scenario-dependent configuration decisions can enable the comfortable deployment of novel multimedia services on the Internet that have the flexibility to adjust themselves without human intervention to different environment and application scenarios. In addition to providing an advanced description-model that covers the different facets of the multimedia communications and scenarios, an optimisation of the control-data and its successful transfer is also a significant research task. The minimization of the response times of the services under adaptation conditions through appropriate signalling represents an important aspect of the overall QoS for the multimedia applications. Current investigations address predominantly the adaptation of the human-perceivable media as it represents the greater load for the services. However, the suitable adaptation of the control data and its appropriate transfer over a wide variety of networks represents an additional challenge for the next-generation services, as the proper QoS for the control information can improve further the adaptation behaviour of the multimedia services, introducing also alternative adaptation possibilities that cannot be covered by the media streaming alone, e.g. through network content adaptors or through sessionand service-mobility scenarios. The results presented in this thesis were motivated through several research projects. Of special importance for this work and for the presented investigations were the EU-funded projects MIND and DAIDALOS and the DFG-funded project AKOM. However, the views expressed in this thesis are those of the author and are not necessarily representative for the projects. The major topic of this work is the specification and the implementation of the End-toEnd Negotiation Protocol (E2ENP). The protocol represents a novel and flexible approach to manage and coordinate multimedia services in mobile and heterogeneous network environments, different from the currently existing static service-coordination methods on the Internet. Significant parts of this work are devoted to the optimisation of the control signalling