MTV gets 'edgier' with Akamai service

Content delivery networks may have made their name by speeding the transport of static content from the edge of the Internet, but that's not enough anymore.

Today's Web sites are more sophisticated, and network managers are looking for ways to boost performance not just of static content, but also of dynamic, personalized content and applications.

That's what prompted MTV Networks, a division of Viacom in New York, to expand its relationship with Akamai. The entertainment company had used Akamai Technologies' FreeFlow service since the spring of 2000 to bring static content closer to end users. But as MTV's Web sites became increasingly dynamic and more requests traveled back to origin servers for personalized information, the ability to cache static content became less of an issue.

"We came to the realization that we were caching requests that were the least problematic for us to serve - or for anybody to serve - and paying a significant premium. That wasn't where the value was," says Nick Rockwell, MTV Networks' senior vice president of online technology. "The value was in serving the difficult [personalized] requests," such as telling logged-on users they had e-mail waiting.

About 14 months ago, MTV looked at an offering from Akamai called EdgeSuite, one of the first services to support dynamic content delivery when it was introduced in October 2000.

MTV implemented EdgeSuite across more than a dozen Web sites, including mtv.com, nick.com, vh1.com and tvland. com. An integral part of EdgeSuite - the piece that Rockwell says is providing the most benefit to MTV - is a markup language created by Akamai and other industry members called Edge Side Includes (ESI).

The HTML-based language, which has been proposed to the World Wide Web Consortium as an industry standard, defines fragments of Web pages, allowing them to be assembled and updated at the edge of the Internet. With ESI, companies can set rules within Web pages, alerting the cache when it is necessary to retrieve fresh information from an origin server and when cached content can be used. Then new content from origin servers can be combined with cached content so that an entire Web page can be assembled at the network's edge - no need to retrieve complete pages from origin infrastructure.

"As we targeted higher-value requests for caching, we needed some real sophisticated processing on the assembly at the edge to do it effectively," Rockwell says. "There are so many cases where individual bits of content or objects, depending on the circumstances, were or were not cacheable."

With ESI, caches can be told how to understand those circumstances. On the MTV Web sites every page has at least one small element that has the potential to be personalized, which means that no page can be fully cached in the traditional manner because the cache must first determine if personalization is necessary.

MTV worked with Akamai to code its sites and use ESI to set up the framework that would tell caches how and when to cache content, and when to go back to its ATG and Netscape servers at the origin.

Users who log on to an MTV site get a cookie. The ESI code within the site tells the cache to look for that cookie. If the user is not logged on and there is no cookie, it can deliver a cached copy of the page. If there is a cookie, it will tell the cache what fragments of the page need to be updated.

On the Nickelodeon Web site, nick.com, users can play games and rack up points. A toolbar shows logged-on users how many points they have. If a user is not logged on, the point tally isn't displayed, personalization isn't necessary, and the page can be delivered directly from the cache.

"That's an example of a small element on the page that renders the entire page uncacheable for any logged-on user because it's never going to be the same for any two users," Rockwell says.

Without ESI, the entire Web page would have to be created at the origin for a logged-on user. With ESI, the fragment of the page containing the toolbar would be updated, sent from the origin, and then inserted into a cached copy of the page and delivered from the edge.

Rockwell wouldn't be specific about cost savings resulting from using EdgeSuite and ESI, but said infrastructure demands have been reduced significantly. More importantly, he says, performance is improving. Mtv.com experienced a 100% boost in performance in handling the big spikes in traffic that followed the MTV Movie Awards in June, compared with the same event last year.

As for drawbacks, Rockwell says using ESI has simplified certain parts of his infrastructure but complicated others. "Now we have to think about cacheability on a per-component basis," he says. "We have to get our metadata right or we'll have unintended consequences like stale content."

In addition, ESI is another markup language that his engineers must learn. Eventually, Rockwell says, he'd like to use Akamai as a more natural extension of his infrastructure by deploying servlets at the edge. Akamai is moving in that direction and has announced that it is developing support for Java 2 Platform Enterprise Edition and .Net processing at the edge.

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