Abstract: This paper analyzes request distribution characteristics of two different services on Internet, DNS and keyword services. And it describes correlations between DNS, keyword services and WWW, obtaining a conclusion that all request distributions of DNS, keyword services and WWW follow Zipf law. Relying on unique resources advantages of China Internet network information center (CNNIC), this paper verifies this conclusion by using actual request distributions of two applications, and introduces its great importance for research.

Key words: Zipf law; DNS; Keyword services; Cache

摘要： 分析了Internet 上DNS 和关键词服务两种不同服务请求分布各自特性以及二者与WWW 请求分布的相互关系，得出DNS、关键词服务与WWW 请求分布都遵从Zipf 定律的结论。借助于中国互联网络信息中心（CNNIC）独一无二的资源优势，通过统计分析两个实际应用系统在一定时间段内的请求分布，验证了该结论，并探讨了其重要的研究意义。

关键词: Zipf 定律；DNS；关键词服务；缓存