4. DELIVERY NETWORK OVERVIEW The Internet delivery challenges posed above (and in more detail in [27]) illustrate how difficult it can be for enterprises to achieve acceptable levels of performance, reliability, and cost-effective scalability in their Web operations. Most of the bottlenecks are outside the control of any given entity and are inherent to the way the Internet works—as a loosely-coordinated patchwork of heterogeneous autonomous networks. Over a decade ago, Akamai introduced the Content Delivery Network (CDN) concept to address these challenges. Originally, CDNs improved website performance by caching static site content at the edge of the Internet, close to end users, in order to avoid middle mile bottlenecks as much as possible. Since then the technology has rapidly evolved beyond static web content delivery. Today, Akamai has application delivery networks that can accelerate entire web or IP-based applications, media delivery networks that provide HD-quality delivery of live and on-demand media, and EdgeComputing networks that deploy and execute entire Java J2EE applications in a distributed fashion. In addition, service offerings have matured to meet additional enterprise needs, such as the ability to maintain visibility and control over their content across the distributed network. This means providing robust security, logging, SLAs, diagnostics, reporting and analytics, and management tools. Here, as with the content delivery itself, there are challenges of scale, reliability, and performance to be overcome.
