Life on the Edge
By Liz Garone
Edge delivery. Virtually unheard of less than a year ago, this buzzword has become one of the hottest in the Internet economy. Companies providing edge delivery (also known as "content delivery" or "Internet caching") services are pulling off skyrocket IPOs and becoming major names, seemingly overnight. Their founders, who responded to the problems created by growing congestion on the Internet as well as sudden, unpredictable spikes in Internet traffic owe a big thanks to an oversight on the part of the Internet's builders.
The companies and institutions that make up the Internet infrastructure may have built the most advanced series of high-speed networks ever, but they didnıt do a very good job of buttressing the points at which these networks come together. These network access points (NAPs) are the nodes at which ISPs can connect with each other. The two major ones are Metropolitan Area Ethernet (MAE) East in Washington, D.C., and MAE West, in Silicon Valley. The system still breaks down in these hot spots, where the private networks converge and much of the content on the Web must pass through in order to eventually make it to a user's computer.
"It's a lot like the highways," says John Katsaros, president of the Internet Research Group, a private consulting firm. "The packets [of information] get on paths to go to their destinations, and there are major intersections where the traffic meets. At those intersections, there are congestion problems when things get busy."
This is where content delivery service providers, with names like Akamai Technologies and Sandpiper Networks, have stepped in. They are finding ways around those points by taking content to the "edge" of the Internet.
Internet caching technology comes in a number of forms: software, hardware, services, or a combination of these. No matter what form it takes, it is essentially designed to do the same thing: to speed up access to frequently requested Web pages by storing a temporary copy of the content on a nearby or better-performing server.
Caching on to the benefits
"What caching is about is trying to deliver a better experience to the ultimate consumer of content," says Brendan Hannigan, an analyst at Forrester Research. "What these [content delivery] providers do is deliver a turnkey caching service so that content providers can subscribe to the service, and their content is blasted out to hundreds and hundreds of caches that these companies have located all over the world."
These services can provide three benefits if correctly implemented, according to Hannigan. First, the user experiences better download times. Second, the site isn't bombarded with constant hits from lots of users, so performance bottlenecks at the central source of content are alleviated. Third, when there are unusual spikes in demand for content, the providers can reroute the traffic. "Because they have such a distributed network of caches, they can load-balance those sites across their network of caches," says Hannigan.
Sandpiper Networks, now part of San Francisco's Digital Island, claims to have the longest-running content delivery network. They've been in business all of 24 months.
To do a good job, a content delivery network must do at least two things, according to Pat Greer, the company's director of streaming services. "One is that it distributes the content out toward the edges of the Internet so that people can perceive better performance from the Web site," he says. "The other is that it directs the users to the best server for them--not necessarily the best geographic server, but the best-connected server."
Greer emphasizes the need to look at factors like Internet topology, connectivity, and congestion, rather than just concentrating on the geography of the server when choosing the best place to send a user to retrieve content. This, he says, is what gives Digital Islandıs Footprint technology the edge over regular caching services.
"We look at the Internet on a minute-by-minute basis. We look at congestion and connectivity to different places," says Greer. "So, we might take your request and look and say, geographically, the closest server is Chicago but connection-wise and [for] speed of response, the best place to send you is Atlanta."
Caching in on currency
Akamai Technologies takes an approach similar to Sandpiper's but offers a larger network of servers and its own FreeFlow technology. FreeFlow allows sites to use caching to store static information--logos and graphics, for example--on one of its more than 2,000 servers in 100 networks in 40 countries, according to Andrew Lickley, an Akamai product manager.
Lickley is quick to point out that although Akamai uses caching as part of its services, the company is different from a traditional cache server. "The chief difference is that we're designed as a system [built from the] ground up for delivering Internet content. Our customers are the content providers, the actual Web properties," he explains. "Caching servers were originally designed to alleviate bandwidth at ISPs, and they're very good solutions for that." But they're not the best for providing the new content, according to Lickley, because cached content--especially things like news stories and weather reports--can get old fast. "We do cache content on our servers. However, weıre constantly checking for popularity and freshness," says Lickley. "It's built into the ARL."
The ARL is the Akamai Resource Locator, which is placed in front of the URL on those items that have been "Akamaized." When an end user requests a page from an Akamaized Web site, the components with ARLs are pulled together from the most efficient servers. An example of this is Yahoo's navigation banner; it stretches across the top of the page, as do 90 percent of AOL's ads, and all are Akamaized, according to the company.
This can speed up a site's performance anywhere from two to 10 times, according to Lickley. "What we offload is the heavy part of the Web page," he says. "By offloading that content onto our network, we allow Yahoo to concentrate on what they do well, which is creating content. We also allow Web sites to handle more transactions. The hidden benefit is their Web sites' not processing 70 to 80 percent of the Web page any longer, so they're free to handle more users and, thus, more transactions."
Caching the next wave
Lickley believes that it is only the tip of the iceberg for content delivery service providers and others interested in caching services. "Itıs a lot like the Gold Rush," says Lickley. "What we're doing is providing the picks and shovels. The more popular the Web becomes, the more properties there are, the more congested it becomes, the better it is for us. The more dot-coms that spring out of nowhere, the more customers there are for us."
Eventually, more and more sites will turn to caching or some other form of delivery, says Forrester's Hannigan. "Any major site would be bonkers over time not to be putting some of their content on to somebody elseıs server utilizing some of these services."