Attacker Independent Stability Guarantees for Peer-2-Peer-Live-Streaming Topologies

Live streaming systems based on application layer multicast (ALM) technology provide an effective and scalable way for content dissemination. Especially push-based systems, maintaining an explicit distribution topology, represent a promising approach. Compared to a classical client-server content distribution and in contrast to other ALM systems, they introduce only low additional transport delay and jitter. However, these systems are vulnerable towards random node failures or intended attacks. In this article, we select packet loss as a natural damage measure and show that there exists an attacker- independent concept of optimal stability of streaming topologies in push approaches. We are able to identify such optimally stable topologies by minimizing an upper bound on the sequence of damages any attacker may achieve on a topology. Furthermore, we show an easily constructible subclass of these topologies and present the unexpected result that deciding membership in the complete class of optimally stable topologies is a co-NP-complete problem.