On the relevance of network topologies in distributed video-on-demand servers

Distributed Video-on-Demand Servers (DVS) are proposed as a solution to the limited streaming capacity and null scalability of large-scale centralized systems. Server interconnection topology plays an important role in Video-on-Demand systems' performance. This paper presents an analysis of different topologies and their influence over storage management and distribution, delivery policies performance, refusing requests occurrence, network consumption and scalability. To accomplish the proposal study, we have designed a complete simulation framework for DVS systems. Experimental results obtained under different workload conditions allow us to draw two important conclusions: First, a better connectivity implies a lower mean request service distance and lesser network requirements, improving multicast policies efficiency. Second, topology regularity is essential, as it allows a greater traffic balancing and provides more alternative routing paths. The analysis of global results shows that hypercube presents the best trade-off among all the evaluated metrics, providing a gradual and unlimited scalability for the D VS system.