Daily Archives: October 16, 2008
The Microsoft CDN study
The Microsoft/NYU CDN study by Cheng Huang, Angela Wang, et.al., 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 Perhaps it’s simply been temporarily withdrawn pending its presentation at the upcoming Internet Measurement Conference.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.
MediaMelon and CDN overlays
MediaMelon has launched, with what they call their “video overlay network“.
I haven’t been briefed by the company yet (although I’ve just sent a request for a briefing), but from the press release and the website, it looks like what they’ve got is a client that utilizes multiple CDNs (and other data sources) to pull and assemble segments of video prior to the user watching the content. The company’s website mentions neither board of directors nor management team, though the press release mentions the CEO, Kumar Subramian.
I’ll post more when I have some details about the company and their technology, but I’ll note that I think that software-based CDN overlay networks are going to be a rising trend. As the high-volume video providers increasingly commoditize their CDN purchases, the value-added services layer will move from CDN-provided and CDN-specific, to CDN-neutral software-only components.