Abstract: Traditional peer-to-peer media streaming system constructs overlay in application level and has little knowledge about the real network topology.This tends to increase average peer receive delay.A new topology-aware algorithm TaP2P is proposed and implemented in this paper.By dynamically adjusting peer’s relative position to the source peer，data is transferred to peers sequentially according to their distance to the source.Simulations show that this method is efficient in reducing average peer receive delay.

Key words: media streaming peer-to-peer network, multicast tree, topology-aware

摘要： 传统流媒体传输对等网在应用层构建覆盖图（overlay），其逻辑结构可能与网络物理拓扑不匹配，造成节点接收延迟大，网络利用效率不高。针对此问题，提出一种拓扑感知的对等网组织算法，称之为TaP2P（Topology-aware Peer-to-Peer），根据节点到数据源的距离动态调整节点在覆盖图中位置，使数据转发路径符合网络物理拓扑。模拟实验表明该算法有效降低了节点平均接收延迟。

关键词: 流媒体对等网, 组播树, 拓扑感知