关键词: P2P网络，搭便车行为，负载度，备用节点表，均衡控制算法

Abstract: In unstructured peer-to-peer network>we need to find hubs to restrain "free-riding" behavior. In this paper,based on referring previous connection numbers from hubs, we took nodes’power difference into account, also introduced the concept about load degree and those nodes holding high load degree are called overload nodes. Then a load balance control algorithm was proposed, in which load from overload nodes is shifted to light-load nodes. Simulation resups shows the algorithm can effectively balancing nodes' load and load distribution is more balanced,so the algorithm can effectively restrain "free-riding" behavior and helps to maintain and improve network performance.

Key words: Peer-to-Peer, Free-riding behavior, Load degree, Backup node table, Balance control