The Microsoft CDN study

The Microsoft/NYU CDN study by Cheng Huang, Angela Wang,, seems to no longer be available. Perhaps it’s simply been temporarily withdrawn pending its presentation at the upcoming Internet Measurement Conference. You can still find it in Google’s cache, HTMLified, by searching for the title “Measuring and Evaluating Large-Scale CDNs”, though.

To sum it up in brief for those who missed reading it while it was readily available: Researchers at Microsoft and the Polytechnic Institute of New York University explored the performance of the Akamai and Limelight CDNs. Using a set of IP addresses derived from end-user clients of the MSN video service, and web hosts in Windows Live search logs, the researchers derived a set of vantage points based on the open-recursive DNS servers authoritative for those domains. They used these vantage points to chart the servers/clusters of the two CDNs. Then, using the King methodology, which measures the latency between DNS servers, they measured the performance of the two CDNs from the perspective of the vantage points. They also measured the availability of the servers. Then, they drew some conclusions about the comparative performance of the CDNs and how to prioritize deployments of new locations.

Both Akamai and Limelight pointed to flaws in the study, and I’ve done a series of posts that critique the methodology and the conclusions.

For convenience, here are the links to my analysis:
What the Microsoft CDN study measures
Blind spots in the Microsoft CDN study
Availability and the Microsoft CDN study
Assessing CDN performance

Hopefully the full PDF of the study will return to public view soon. Despite its flaws, it’s still tremendously interesting and a worthwhile read.

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Posted on October 16, 2008, in Infrastructure and tagged , , . Bookmark the permalink. 3 Comments.

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