CIO — When customers visit one of Terra Lycos’s websites, they don’t get every object on the pages straight from the online service company’s global Web portal. Instead, a content delivery network (CDN) provider?Akamai Technologies?serves up the images and streaming media from caches (or edge servers, as Akamai calls them) dispersed around the globe. Some localized news even arrives automatically based on which server is nearest to the customer. The result is a lighter load on Terra Lycos’s servers and faster performance for users. But changes to how companies create their pages are forcing CDNs to reevaluate their services.
The original idea behind Akamai and other CDNs was pretty straightforward: Deploy large, often-requested files at the so-called edge of the Internet, where customers could retrieve them quickly. "Back in the days of the bubble, customer experience was the big priority," says Vince Russo, chief architect at Terra Lycos in Waltham, Mass. "But it also helps us reduce the load to our data centers and the number of servers needed." In fact, when Lycos started caching its images with Akamai about three years ago, Russo cut his collection of image servers by more than half.
Studies by Giga Information Group have confirmed that CDNs can offer enterprises a significant return on investment, and a reduction in infrastructure costs sounds pretty good during a recession. Unfortunately for CDNs?and their customers?filling repeat requests is getting trickier. "Websites have gotten so much more complicated over the last years," says Joel Yaffe, a New York City-based analyst with Giga. "It’s not just static content. Now more and more it’s dynamic content, with Web servers asking for complicated information."
Today, Web servers often build pages on the fly, using content tailored to a customer’s location, type and other ever-changing criteria. It’s a time-consuming process, and one that many companies would like to avoid.
"Companies consider repeat requests an annoying burden on the infrastructure," says Neal Goldman, an analyst with The Yankee Group in Boston. "If somebody keeps asking you the same question over and over again, someday you’re going to post an FAQ and say, ’Go there, I wrote it down.’ Then you’ll have more resources available to handle nonstandard requests. The question is, How much of that process can you cache?"
The World of CDNs
Both ISPs and companies serving up websites have long used caching to speed up content delivery. Usually, popular content such as homepages and "heavy" files such as graphics and streaming media are placed in a cache for quick access closer to the customer. And customers find the services valuable: The three largest cache providers?Cacheflow, Inktomi and Network Appliance?have combined revenues of approximately $350 million.
