P2broadcast: A hierarchical clustering live video streaming system for P2P networks

摘要

This work describes a novel live video streaming system for P2P networks, referred to as P2broadcast. The video streaming service has bandwidth requirements to guarantee presentation quality. Therefore, a scalable strategy to quickly find a path from a media server to a client with abundant bandwidth is very important. A common approach in the literature is the bandwidth first (BF) scheme, which allows a newcomer to adopt a BF tree traversal scheme to find its parent peer on the P2P overlay tree to retrieve the media content. The BF scheme is likely to build a deep overlay tree, resulting in long start-up latency as the number of peers on the overlay tree grows. P2broadcast reduces start-up latency by organizing peers into hierarchical clusters and making the overlay tree become a 'short-and-wide' tree. The hierarchical clustering structure enables a newcomer to find its parent peer among the set of peers that are more likely to provide large available bandwidth only. Limiting the set of potential parent peers not only reduces startup latency but also improves the system availability. Additionally, unlike the BF scheme that only concerns available bandwidth, P2broadcast utilizes a cost function to evaluate the appropriateness of a potential parent peer. The cost function considers the depth of the newcomer on the overlay tree, making the overlay tree become a short-and-wide tree. In addition to start-up latency reduction, the short-and-wide tree feature also alleviates the service interruption probability due to the leaving or failure of a peer. Our simulation results show that P2broadcast greatly outperforms the BF scheme in terms of system availability, and achieves around 66% savings in start-up latency and 10% decrement in service interruption probability.