Toward QoE-aware Optimum Peer Cache Sizes for P2P Video-on-Demand Systems

This paper explores the effect of varying peers' local cache sizes on user perceived video quality in Video-on-Demand p2p streaming. First, we ascertain the relationship between the average video distortion on peers and peer cache size. Second, we analyze the aggregate access network usage of uplink bandwidth for different peer cache sizes. Finally, we measure the p2p server bandwidth usage as the peer cache size is changed. After finding analytical fits to these three functions we compute the optimal peer cache size that minimizes the total cost of p2p VoD video streaming. Our extensive simulations highlight the key role peer cache sizes play in the interplay between the video quality delivered to users and the amounts of p2p server and peer bandwidth usage. Subsequent data analysis provided in this work presents a framework for computing an optimum operating point for p2p VoD systems in terms of server and peer bandwidth required.