Construction and maintenance of P2P overlays for live streaming

摘要

P2P live streaming requires low latency and low media discontinuity to provide users good quality of experience. When peers are connected to a large number of partners, the communication overhead increases and sophisticated overlay maintenance strategies are required to maintain undisrupted media distribution. In order to deal with these challenges, we present the Peer Classification for Partnership Constraints technique for building and managing P2P overlays for live streaming. The proposed algorithm defines classes of peers based on their contribution to video chunk distribution. Classes are used to constrain partnerships among peers. The number of potential partners in each class is constrained, avoiding competition for partnerships between high-cooperation and low-cooperation peers. Since each peer has a given number of slots dedicated to high-cooperation and low-cooperation peers, we guarantee that the network keeps operating, even when incorporating a considerable share of free riders. The strategy is simple, significantly reducing system complexity. Moreover, it can also be used in conjunction with other strategies devised in the literature for greater gains in efficiency. Experiments show that our Peer Classification for Partnership Constraints technique allows a streaming system to handle 50% of free riders under flash crowd events with low latency and discontinuity.