EdgeCache: An optimized algorithm for CDN-based over-the-top video streaming services

In this paper, we propose a model for video streaming systems, typically composed of a centralized origin server, several CDN sites, and edge-caches located closer to the end users. We comprehensively consider different systems design factors including the limited caching space at the CDN sites, allocation of CDN for a video request, choice of different ports from the CDN and the central storage, bandwidth allocation, the edge capacity, and the caching policy. We focus on minimizing a performance metric, stall duration tail probability (SDTP), and present a novel and efficient algorithm accounting for the multiple design flexibilities. The theoretical bounds with respect to the SDTP metric are also analyzed and presented. The implementation on a virtualized cloud system manged by Openstack demonstrate that the proposed algorithms can significantly improve the SDTP metric, compared to the baseline strategies.