AERO: Adaptive Emergency Request Optimization in CDN-P2P Live Streaming

Live streaming platforms employ advanced mechanisms to guarantee continuous and scalable video playback to large user bases. One such mechanism is CDN-P2P streaming, where servers are hosted on content distribution networks and client resources are used to help disseminate content in a peer-to-peer overlay. In CDN-P2P streaming, a peer that is about to miss the playback deadline of a content piece issues an emergency request to the CDN. Emergency requests allow the retrieval of nearly missed pieces and guarantee continuous playback. We show that emergency requests deliver a chunk close to its deadline and leave no time for dissemination through the peer-to-peer overlay, decreasing scalability. We present AERO, a mechanism that dynamically adjusts the rate at which CDN-hosted servers seed content pieces into the peer-to-peer overlay as a function of network conditions. Our evaluation of AERO under diverse conditions shows it reduces emergency requests, guarantees efficient peer-to-peer dissemination, and provides significant server upload bandwidth savings.