中文摘要：

Chord协议是使用分布式散列表（DHT）技术最简单的环状拓扑结构的p2p模型，但是目前对Chord协议的改进，存在着增大路由表和节点状态信息维护开销过大的问题．提出了一种折衷的改进算法，将Chord环分成区域，每个区域选取一个超级节点．通过区域超级节点层次化定位方法，在不增大路由表和节点状态信息维护的情况下，提高了系统的定位效率．实验模拟结果表明节点路由表只需维护O（logk）其它节点信息（k为区域数量），就可大大降低平均查询路径长度．

英文摘要：

Chord protocol is the simplest ring topology of the p2p model with the use of distributed hash table （DHT）. In order to improve the lookup efficiency of Chord, many approaches are explored to reduce the average lengths of lookup path to a constant by increasing the routir/g table size and maintaining too much state information of nodes. It is proposed a regional lookup algorithm based on super - node that addresses these problems. It is shown how to divide the Chord ring into many regions, and located with super - node in a hierarchical way. Results from theoretical analysis and experiments show that the improved lookup algorithm achieves higher efficiency and each node maintains only O（logk） routing information with k regions.