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Access to content is what next-generation networks are all about. Opinions vary, however, about the best way to make it happen.
Most casual observers know of just one business model for content distribution networks (CDNs)--Akamai's. In this model, content providers pay CDNs, which own no transport infrastructure, to have content replicated in servers located in datacenters closer to end-users than the origin servers.
This model has captured the imagination of Wall Street, and continues to draw the lion's share of the attention. There are, however, other models designed to further the interests of a different cast of characters. We set out to identify and examine various CDN business models, delving into questions of who distributes which content for whom, why, and who pays whom.
The Cast Of Characters
CDNs burst onto the scene in 1999 to address the fact that the Internet was not designed to handle large transmissions of Web content over long distances. Network congestion and traffic bottlenecks, exacerbated by burgeoning payloads of Web traffic, degrade individual website performance and compromise network performance.
CDNs address the problem by storing and serving content from many distributed locations rather than from a few centralized origin points-- thus bypassing network congestion. Using caching technology, CDNs store replicas of content near users, rather than repeatedly transmitting identical versions of the content from an origin server. The result accelerates and improves the quality of content delivered to end users, while lowering network congestion and bandwidth costs for ISPs.
The CDN stage is populated by a cast of five characters, each with its own needs and agenda. The CDN playbill includes:
* Content providers, who need to get their content to end-users.
* Hosting providers, whose Internet-connected datacenters house content providers' servers.
* Backbone carriers, who provide wide-area transport for ISPs.
* Access ISPs, who connect end users to the Internet.
* End users, who are consumers of content.
These five groups make up a content distribution value chain, the purpose of which is to connect consumers to purveyors of content. Note that there is overlap among access ISPs, backbone carriers and hosting providers. Some backbone carriers offer access and hosting services, and many access ISPs offer hosting services. But even when one provider assumes multiple identities, distinctions...