Cost-effective distributed architecture for large-scale video-on-demand

In spite of the attractiveness of video-on-demand (VoD) services, their implementation up to the present has not been as widespread as could have been desired, due to centralized VoD systems having a limited streaming capacity and poor scaling. One-level proxy-based systems have been proposed to increase system capacity, but their scalability is still limited by the main net bandwidth. To achieve a scalable large-scale system (LVoD), we propose a hierarchical architecture, called double P-tree, based on a tree topology of independent local nets with proxies. To decentralize the architecture and facilitate the system´s growth, the functionality of the proxy has been modified in such a way that it works at the same time as caching for the most-watched videos, and as a distributed mirror for the remaining videos. Moreover, the double P-tree topology interconnects local networks in order to improve connectivity and efficiency. The evaluation of this new architecture, through an analytical model, shows that the double P-tree architecture is a good approach to the design of flexible LVoD systems, without the need for using a complex server or high-bandwidth networks.