Evolution and challenges of DNS-based CDNs

DNS-based server redirecting is considered the most popular means of deploying CDNs. However, with the increasing use of remote DNS, DNS-based CDNs face a great challenge in performance degradation. To address this issue, encouraging progress has been made in both industry and research communities. In this article, state-of-art solutions for the remote DNS problem are discussed at first. Next, privacy concerns about DNS-based CDNs, including client location as well as redirection privacy, are identified and a representative solution is summarized. Finally, the solution is compared to those in prior works under different measures, and a discussion on DNS-based CDN applications is provided. A model is also established to deepen the understanding of CDN performance. We believe that this survey will shed light on the application of DNS-based CDNs, and it is expected to provide design guidelines to CDN service providers.