中文摘要：

分析比较了目前DHT网络中基于虚拟服务器（virtual server）的负载平衡算法，根据节点间间距的分布概率，建立了基于虚拟服务器的DHT网络负载分布数学模型，详细分析和计算了DHT网络中单虚拟服务器问题（SVSP）发生的概率，提出了一种基于虚拟服务器拆分的负载平衡算法（VSSLBA），仿真实验验证了理论推导的正确性与算法方案的有效性。

英文摘要：

The method using virtual servers for balancing the load in DHT-Based P2P systems was studied. The load distribution in DHT-based overlay network using virtual servers were modeled, the occurrence probability of single vir- tual server problem （SVSP） was analyzed and computed in details, and a novel VS-split load balancing algorithm （VSSLBA） was proposed to deal with the SVSP by splitting virtual server into small ones. Simulations verify the cor- rectness of orobabilitv analysis and the oerformance of VSSLBA.