An overlay management strategy to improve QoS in CDN-P2P live streaming systems

With the tremendous growth in demand of live video streaming services over Internet, content delivery networks (CDNs) get overloaded. The CDN-P2P live streaming systems are being deployed to reduce the stream delivery load of CDNs. The inherent peer churn and heterogeneity in upload contribution of peers make it challenging to maintain the quality of service (QoS) in these systems. To deal with this challenge, we propose an overlay management strategy that organizes peers in the overlay based on their serviceability, which we define based on stability, stream chunk availability, upload and download capacities of peers. Peers are arranged in a hybrid tree-mesh overlay at the edges of CDN. The peers with higher upload capacity are part of an extended CDN tree to facilitate stable seeders. A part of the upload capacity of the existing peers is reserved to form virtual sources that provide startup chunks for quick playback. The peers joining the mesh overlay select partners with highest serviceability to ensure better streaming quality. They also adapt the topology by replacing partners based on serviceability and upload capacity utilization to maintain QoS during churn. Overall, the proposed serviceability-aware overlay management strategy (SOMS) enhances the QoS and upload capacity utilization of peers while dealing with heterogeneity in upload contribution and peer churn. Comparison with the existing CDN-P2P systems shows that the upload capacity utilization of peers is improved by 30%, while the startup delay and streaming quality are improved by 20% and 25%, respectively.