中文摘要：

内容分发网络CDN根据网络的实时环境，对用户请求的内容进行合理的分发，可以有效避免网络拥塞，优化用户体验。CDN已经成为网络基本架构中非常重要的部分。针对CDN的测量，对于分析CDN网络性能、优化CDN网络结构进而提升服务质量都有重要的意义。然而，由于缺乏有效的测量方法，以及中国大陆网络基础设施服务的复杂性，针对中国大陆CDN测量的研究还比较欠缺。提出一种基于HTTP代理服务器作为测量源的CDN测量技术，通过对中国大陆的主要CDN服务商进行广泛深入的测量，获取到不同CDN服务商的节点分布，并分析了CDN节点的部署策略、负载均衡以及不同CDN服务商的节点调度策略。

英文摘要：

Content Delivery Networks（CDNs） are arranged for efficient delivery of the user＇s requests＇ according to the real-time environment of the network, avoiding network congestion effectively as well as optimizing the end-user experience. CDNs have become a critical part of today＇s Internet. Measurements of CDNs are required for understanding CDN performance and analyzing its architecture optimization, which aims to improve the quality of service. Due to the complexity of the network infrastructure in mainland China, researches on measurement and performance analysis of CDNs in mainland China are relatively few. We propose a novel CDNs measurement method based on the HTTP proxy that we use as vantage points. After extensively measuring the CDNs in mainland China, we obtain CDNs nodes distri- bution. Finally, we analyze the deployment strategy, load balancing, and node scheduling policies of different CDNs service providers.