DNS对CDN流媒体服务质量的影响

The Impact of DNS on CDN Streaming Performance

为了提供高质量的流媒体服务,内容发布网络(CDN)利用域名解析系统(DNS),将用户重定向到附近的内容服务器。近年来,域名解析系统的发展,尤其是基于IPAnycast的域名解析系统的兴起(例如,Google Public DNS,Open DNS),必将对CDN网络的内容发布机制造成影响。同Web、Email等其它Internet服务相比,流媒体服务对网络资源有较高的要求,DNS对其影响更加明显。本文首先阐明基于IPAnycast的域名解析系统对CDN网络内容发布模型的冲击,然后分析其影响流媒体服务质量的各种因素,最后通过实验来比较当使用不同域名解析服务时CDN网络承载的流媒体的服务质量。

To provide high quality streaming service, content distribution network （CDN） exploits the domain name system （DNS） to redirect users to the close-by content servers which are widely worldwide distributed. In recent years, the development of domain name system, especially the rising of IP Anycast based domain name system （e.g., Google Public DNS and Open DNS）, will definitely impact the content distribution mechanism of CDN. Compared with other Intemet services, streaming service requires relatively more network resource. The influence from DNS will be more obvious. This paper firstly states how IP Anycast based DNS impact the redirection of CDN networks, analyzes the factors that impact the QoS of streaming service, and f＇mally compares the QoS of CDN streaming service when using different DNS resolving service.