Improving stability for peer-to-peer multicast overlays by active measurements

The instability of the tree-like multicast overlay caused by nodes' abrupt departures is considered as one of the major problems for peer-to-peer (P2P) multicast systems. In this paper, we present a protocol for improving the overlay's stability by actively estimating the nodes' lifetime model, and combining the nodes' lifetime information with the overlay's structural properties. We use the shifted Pareto distribution to model the nodes' lifetimes in designing our protocol. To support this model, we have measured the residual lifetimes of the nodes in a popular IPTV system named PPLive [PPLive. http://www.pplive.com], and have formally analyzed the relationships between the distribution of the nodes' lifetimes, ages and their residual lifetimes under the shifted Pareto distribution model. We evaluate the overlay construction strategies, which are essential in improving the overlay's stability in our protocol, by comparing them with a number of other strategies in simulation. The experimental results indicate that our proposed protocol could improve the overlay's stability considerably, with informative but not necessarily accurate lifetime model estimation, and with limited overhead imposed on the network as well as negligible sacrifice regarding the end-to-end service latencies for the nodes on the overlay. (C) 2007 Elsevier B.V. All rights reserved.