The impact of dynamic adversarial attacks on the stability of heterogeneous multimedia networks

Modern large-scale multimedia networks, such as the Internet, are characterised by heterogeneity due to the versatile nature of their communication subsystems. We focus on heterogeneous multimedia networks where individual greedy, contention-resolution protocols are simultaneously running (composed) over different network queues. A question that arises in such multimedia systems concerns the possibility of developing design criteria in order to evaluate stability degradation under adversarial attacks that change dynamically network link capacities/slowdowns. A packet-switched network is stable if the number of packets in the network remains bounded at all times against any adversary. We consider the Adversarial Queueing Theory framework, where an adversary controls rates of packet injections and determines packet paths. The adversary is enhanced to include manipulation of link capacities/slowdowns. Within this framework, we show the impact of dynamic adversarial attacks in network stability under various protocol compositions and dynamic adversarial attacks trying to characterise stability in terms of network topologies for simple-path trajectories. The examined network topologies have been proved forbidden for stability when network link capacities/slowdowns are fixed. Our results indicate that the composition of protocols under dynamic adversarial attacks leads a network to worst instability behaviour than using a single protocol or a composition of protocols with fixed network link capacities/slowdowns.