The Impact of FIFO Compositions with Other Protocols on the Stability of Multimedia Networks Facing Dynamic Adversarial Attacks

Abstract

Multimedia packet-switched communication networks, such as the Internet, are heterogeneous in their nature due to the usage of different protocols for resolving packet conflicts on network queues and the existence of multiple types of network links. The efficiency of multimedia communication depends on the variety of contention-resolution protocols that are simultaneously running (composed) over different hosts and the capacities of links. We are mainly interested in FIFO compositions with other protocols because FIFO is widely used in packet-switched networks for best effort services due to its simplicity. A very natural question that arises in such common settings of multimedia networks concerns the degradation of network stability under adversarial attacks that change dynamically network link capacities. A packet-switched network is stable if the number of packets in the network remains bounded at all times against any adversary. We adopt an enhanced adversarial framework, where an adversary controls packet injection rates, packet paths and network link capacities. Within this framework, we study the impact of specific compositions of FIFO with other protocols on the network stability. Interestingly, our results suggest that such protocol compositions may lead a network to worse instability when it faces adversarial attacks that dynamically change link capacities than adversarial attacks with unit capacities or when a single content-resolution protocol is used. We feel that this study could help on the design of trustworthy multimedia networks.