InformationWeek

Distributing and managing traffic among various servers and specialized devices is one of the most effective tactics for improving Web-site performance, according to Jupiter Communications research director Peter Christy. "There has been enormous progress in how you build big enough computer systems to run large, fast Web sites. You do it by using many systems and building a bigger system using traffic-management devices to distribute the load," he says.

Proven approaches to improving site performance include technologies such as load-balancing software that smooths out network traffic loads, the clustering of multiple servers so a single server failure won't crash a site, and the use of specialized accelerators to handle certain kinds of traffic and transactions. For example, a Secure Sockets Layer encryption accelerator can take over the burden of scrambling and unscrambling crucial and confidential information such as credit-card numbers or health-care records that are now part of many sites. This approach eases the load on the main Web server--and has prompted several vendors such as Intel and newcomer Netscaler Inc. to develop methods of accelerating certain types of Internet traffic and transactions.

"The SSL accelerator is an extremely valuable product--SSL brings servers to their knees," says Meta Group research analyst Peter Firstbrook. "If it takes me eight seconds to download a page in clear text and then I have to go to SSL to do transactions, it's 2.5 times longer. That means it's going to take 20 seconds to download that page."

When a site uses SSL to encrypt transmissions, the number of connections per second that server can handle drops dramatically. "The number of clients per second you can support drops from 357 to three," says Firstbrook. "By offloading to one of these SSL accelerators, you can pretty much get back to clear text speed."

Intel last year introduced an SSL accelerator that lets sites download pages 47 times faster, Firstbrook says. By year's end, Intel also intends to roll out NetStructure 7280 XML Director and 7210 XML Accelerator systems to facilitate the processing of Extensible Markup Language between business sites. While they don't directly accelerate XML documents, the Intel systems will perform a higher level of load balancing for XML documents, Firstbrook says. "Load balancers distribute traffic. But on the highest form, they distribute content, and Intel has taken that further to target specific things like XML tags and load-balance that," he says.

Another variation on that theme is offered by newcomer Netscaler, which has introduced Webscaler to handle the burden of maintaining connections to a host server. CashSurfers Inc., an online advertising company in Bakersfield, Calif., says the Netscaler hardware, which maintains the connections necessary for TCP/IP traffic between a Web site's servers and a customer's system, has boosted capacity. "For every page, you have many objects. Each of these objects needs to be retrieved from the Web site. There's a lot of overhead in opening or closing a connection," says Netscaler founder and CEO Michael Susai. "What this box does is transparently offload all the overhead associated with TCP/IP openings and closings."

CashSurfers sends out banner ads from its network of six clustered, dual-Pentium Web servers that run Windows NT, according to chief technology officer Noah Mapstead. CashSurfers placed the NetScaler box in-between the servers and its load balancing systems. But it also left some of the machines unconnected to NetScaler so performance could be compared. "The machines that aren't connected served 120 requests per second; the connected machines served about 240 requests per second," says Mapstead. "It adds up to a little over a billion banners a month. We can get twice the performance out of our machines that we normally would."

Another tactic growing in popularity is caching, a technique that stores large graphics or frequently requested data and images in a specialized device or network so they can be delivered more quickly. In the server room, Web operators can install a reverse proxy cache in front of the Web servers and store common images and other often-requested information in its memory. "A network reverse proxy cache can serve 500 Mbytes a second. All it's doing is caching popular stuff in its memory," says Jupiter Communications' Christy. "It's a good way to make sure you have enough capacity to handle some events."

Large sites take caching to the next level by using caching networks, which store images and other information on servers in data centers around the world. When a Web surfer in California tries to access a Web site in New York, caching services and networks will send that Web page from a server in San Jose, cutting down the transmission time and lessening the burden on the original network and main server.

Mark Noblitt, VP of technology for Freeshop.com, a direct marketing firm that offers free trials of products and magazines, uses a service from Akamai that he says has cut download times by 34%. "That's mostly from having the data closer to the user and an optimized communication method," he says. The other part about 'Akamaization' is that it removes additional calls to my organization for all the image calls," Noblitt says.

Akamai, which is about a year old, has enjoyed huge growth. "We have more than 4,000 servers in 45 countries on 160 different ISP networks," says David Goodtree, VP of strategy for Akamai. "We're deploying 50 to 100 new servers every week, and another country every week." The Akamai service will help a Web site run from two to 10 times faster, Goodtree maintains.

Based on monthly averages, Akamai charges $1,995 per megabyte per second of content. It runs a mix of Windows NT and Solaris on Intel systems, and plans to start providing caching of dynamic content, streaming media, and financial transactional applications.

There are similar services. Speedera Networks Inc., an Akamai competitor, offers an outsourced service that integrates content delivery and global traffic management. Speedera's Content Delivery Network supports content and applications online in a caching service similar to Akamai, but it also has a Global Traffic Management system to route traffic around downed parts of the internet. IndiaPlaza.com, an international E-retailer that sells more than 50,000 products, has been using Speedera's network for four months. CTO Davinder Luthra praises the results and plans to expand usage of the Global Traffic Manager. "Speedera helps eradicate inconsistent content delivery and presentation to create a uniform user experience, even if they are in Dubai," says Luthra.

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