Bandwidth constrained tree construction for live streaming systems in P2P networks

The traditional client-server architecture widely adopted on the Internet is not adequate to meet the increasing user loads and bandwidth demands in live streaming systems especially for multimedia content delivery. Peer-to-peer P2P) overlay networks provide excellent system scalability and high resource utilization, which make it an attractive solution to this problem. This paper considers a hybrid hierarchical P2P overlay network structure that consists of both super and normal peers. The media streaming architecture is built upon a tree structured network of super peers and the tree construction process has a significant impact on the overall system performance. We construct network cost models and formulate a Bandwidth Constrained Tree (BCT) construction problem, which aims at maximizing the number of peers that satisfy a specified bandwidth constraint. We prove that BCT is NP-complete and propose optimal algorithms in two special cases and a heuristic approach in a general case. The performance superiority of the proposed method is illustrated by an extensive set of experiments on simulated networks of various sizes in comparison with existing greedy and degree constrained algorithms.