论文标题
在IPv6和ECS时代重新审视DNS解析器的比较性能
Revisiting Comparative Performance of DNS Resolvers in the IPv6 and ECS Era
论文作者
论文摘要
本文重新讨论了互联网用户可用的DNS分辨率服务的性能问题。尽管几项先前的研究解决了这一重要问题，但重要的发展，即IPv6最终获得了吸引力，并且通过主要DNS解决方案服务将EC扩展到DNS，但在这些新现实中需要重新评估。我们发现，DNS分辨率服务在其查询响应时间中在某些位置的数量级差异很大。我们还发现，就DNS延迟而言，已建立的解析器（Google DNS和OPENDNS）远远落后于相对新移民（Cloudflair和Quad9），并追踪了大幅度降低缓存命中率的原因，我们进一步追踪了在回答器平台内的缓存共享。此外，我们发现，公共解析器在很大程度上缩小了ISP解析器的差距，该差异以延迟衡量的CDNS的客户对边缘服务器映射质量。最后，在大多数位置，我们在解析器生产的客户到CDN-边缘服务器映射的延迟中观察到IPv6处罚。此外，这种罚款虽然通常很重要，但仍未超出Happy Eyeballs算法所采用的典型阈值，而偏爱IPv4通信。解析器。因此，在这些位置的双堆叠客户可能会出现次优性能。
This paper revisits the issue of the performance of DNS resolution services available to Internet users. While several prior studies addressed this important issue, significant developments, namely, the IPv6 finally getting traction and the adoption of the ECS extension to DNS by major DNS resolution services, warrant a reassessment under these new realities. We find that DNS resolution services differ drastically -- by an order of magnitude in some locations -- in their query response time. We also find established resolvers (Google DNS and OpenDNS) to lag far behind relative newcomers (Cloudflair and Quad9) in terms of DNS latency, and trace the cause to drastically lower cache hit rates, which we further trace to less cache sharing within the resolver platform. In addition, we find that public resolvers have largely closed the gap with ISP resolvers in the quality of CDNs' client-to-edge-server mappings as measured by latency. Finally, in most locations, we observe IPv6 penalty in the latency of client-to-CDN-edge-server mappings produced by the resolvers. Moreover, this penalty, while often significant, still does not rise above typical thresholds employed by the Happy Eyeballs algorithm for preferring IPv4 communication. resolvers. Thus, dual-stacked clients in these locations may experience suboptimal performance.
