378 Copyright © 2010, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 16 Trust and Stability in Heterogeneous Multimedia Networks Dimitrios Koukopoulos University of Ioannina, Greece INTRODUCTION Nowadays, there is a necessity for the develop- ment of fast and reliable large-scale communica- tion platforms for the distribution of commercial multimedia products. Within this context, it is im- portant the presence of a trust relationship among all the entities that cooperate (vendors, consumers, network infrastructure). However, in a distributed system or a network, the entities involved in a trust ABSTRACT In this chapter, the author views trust as the confdence in the association of a stable network execution to the effcient distribution of multimedia products in the fnal user. A network is stable under a greedy protocol (or a composition of protocols) if, for any adversary of injection rate less than 1, the number of packets in the network remains bounded at all times. The author focuses on a basic adversarial model for packet arrival and path determination for which the time-averaged arrival rate of packets requiring a single edge is no more than 1. Within this framework, the author studies the property of stability under various compositions of contention-resolution protocols and different packet trajectories trying to char- acterize this property in terms of network topologies. Furthermore, the author enhances the adversary allowing the monitoring of network link capacities/slowdowns. Within this context, the author shows how the stability properties of network topologies change when network link slowdowns/capacities can change dynamically. Interestingly, his results indicate that a composition of protocols leads to worst stability behaviour than having a single unstable protocol for contention-resolution. This suggests that the potential for instability incurred by the composition of protocols may be worse than that of some single protocol. Consequently, this study could help on the design and maintainance of trustworthy heterogeneous multimedia systems. DOI: 10.4018/978-1-61520-682-7.ch016