By Francois Le Faucheur, System Architect, Cisco Systems
With the CDN World Summit coming up this week in London (Oct 26-28), it seems a good time to describe something that’s been a working passion of mine: CDNI, where the “I” stands for “Interconnect.”
What’s CDNI? It’s a new working group within the Internet Engineering Task Force (IETF), co-chaired by myself and my colleague Rich Woundy, Senior VP/Software and Applications for Comcast. The working group mission is to develop standards for the interconnection of CDNs run by different operators, so they can inter-operate and collectively provide a multi-footprint CDN — thereby pooling resources that are owned and operated by multiple operators.
It’s all about how to link up the world’s CDNs, so that they can exchange information and work collectively. Just like the Internet was about linking up the world’s IP networks.
The notion of interconnecting or “federating” networks run by different operators so as to offer global services is not new. Such activity has been defined and successfully deployed before for other technologies, such as fixed telephone networks, mobile phone networks and short message services.
Even the more specific concept of “federating” content delivery networks (CDNs) isn’t necessarily new and has been talked about in the past. However, the stars seem to be aligning now so that it can become a reality: Content providers are looking for large scale delivery services with enhanced and predictable quality; service providers are deploying CDN infrastructure within their respective footprints, and standards are now being developed by the IETF working group.
It turns out that a fully featured CDN federation requires interconnection of CDNs in multiple dimensions, which are all addressed by the IETF CDNI. First, it requires interconnection of request routers, so they can achieve effective redirection across CDNs.
Second, it requires exchange of content distribution metadata so that content provider distribution policies can be enforced consistently across CDNs. Third, it requires a control protocol across CDNs so that important actions (such as purging of content items from cache) can be triggered across CDNs.
And finally, it requires exchange of logging/reporting information so that essential applications such as accounting and billing, reporting and analytics can be performed over a CDN federation.
The IETF CDNI effort kicked off as an official working group last July, in Montreal, Canada. Three documents have already been progressed to the status of “working group” document: A problem statement, a requirements document, and a compilation of use cases. In addition, many other individual Internet-Drafts proposing technical solutions for the actual CDNI protocols have been submitted to the working group and are under review. It’s safe to say that this is a very (very) active group!
If you’re interested, click here for information about the status, charter and all active Internet-Drafts of the IETF CDNI. Our next meeting is November 13-18 in Taipei, Taiwan.
Until then – stay tuned for a lot of activity around this subject at the CDN World Summit! Yes, I am hinting at something. If federated CDNs are up your alley, you won’t want to miss Scott Puopolo’s keynote on October 26! Check out http://cdnworldsummit.com/ for the keynote schedule!