Understanding Inter-AS Traffic Generated by CDNs with Different Resolving Services

摘要

Content Distribution Networks (CDNs) allowing clients to fetch resources from widely distributed servers,are prevailing on today’s Internet.To measure the performance of large-scale CDNs,it requires comprehensive probing from large numbers of geographically distributed probing points.This paper proposed an approach to measure and estimate the performance of CDNs.In particular,this paper focused on Akamai CDN.The measurement shows that Akamai's traffic turns from intra-AS to inter-AS when clients switched from local resolver to Google Public DNS or OpenDNS.Furthermore,the measurement found that more than 95％of the traffic traveled at least three AS hops when Google Public DNS and OpenDNS are used,which is discrepancy relative to the scenario when using local resolvers that majority of the traffic remain intra-AS.