Gold class Internet

• Article 2 of 77
• Information Age, November 2000
• View the original article online

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Database performance can also be hit in unexpected ways. HFC Bank was getting particularly poor back-end performance on its branch-based, on-line credit-check system, but only on searches coming from particular geographic areas. It turned out the areas had particularly large Latino populations and searches on the name Rodriguez, even with a qualifying initial, were producing lists of names hundreds of entries long. By requiring more qualifiers, the back-end performance was improved.

Companies that have started out with relatively small hits on their sites have found their servers unable to cope with demand as it increases and have had to use load-balancing to improve performance. This uses multiple web servers and a load-balancer, which is either hardware-based or software-based. Windows 2000 Advanced Server and Datacenter Server have load-balancing capabilities, as do Linux, Solaris and most versions of Unix. Hardware-based load-balancers are available from ArrowPoint, Alteon, F5 Networks, HydraWeb and Radware among others.

The load-balancer sits between a network’s routers (which direct traffic to the right area of the network) and its servers and distributes the requests among the servers. An intelligent balancer is able to determine how much the servers’ resources are being stretched and can direct a transaction request to the server with the least load. MCI, BT and Dow Jones use HydraWeb’s load-balancer to monitor how well applications are coping before deciding whether to pass them any more requests.

An added advantage to companies using load-balancing is that whenever an old server starts to be outpaced by the demands placed on it, it can remain online and another server added, doubling the web serving capability. And if one of the servers breaks down or needs maintenance, a reduced service remains rather than a complete outage. According to Donkin, with a static site, “load-balancing is the most useful thing you can do.” And Crosby adds that “load-balancing is another area that can cause problems. But just by changing the configuration, you can see some fairly dramatic results.” Another good point: the servers don’t all have to be on the same network but can be on a WAN (wide-area network: two or more networks connected together. Typically, the connection between the two is slower than the networks themselves) or the Internet. Radware’s WSD-NP, for instance, can redirect requests from clients across the Internet to servers physically nearer to them.

At Virgin’s two latest online venture, Virgin Cars and Virgin Wine, switches from Alteon provide web traffic load-balancing, but they also improve the performance of the firewalls by distributing packets between them for processing, enabling traffic to be processed by both firewalls equally. “We’ve been able to increase the resilience as well as the performance of front-and back-end systems that are critical to our online operations,” maintains Richard Shearn, IT director at Virgin Cars.

Companies with global web sites have also had to modify their operations for the benefit of their overseas customers. Traffic doesn’t travel from the client directly to the server and back again. It hops from node to node on the Internet. The further away the client is from the server and the more congested the Internet, the more hops traffic has to make to get there and back.

One way to solve this problem is to use the services of a content delivery network such as Akamai. Akamai has several thousand servers around the world with identical content. Requests for content on sites such as apple.com and cnn.com are redirected to an Akamai server close to the client, so the client is served more quickly, simply because of its proximity to the server.

The Content Bridge Alliance, a group of companies with similar aims to Akamai, is working on standards to make their own servers interoperable with each others’ in order to have a greater number of local points of presence than Akamai.

“Bandwidth. It’s always bandwidth,” says Mercury Interactive’s Gareth Heaton, who helps maintains the company’s own site. In his experience, the problem isn’t the network itself or even the web pages. It’s either the link to the Internet from the company network or the internet itself not being able to cope with the amount of traffic on them. It’s impossible to serve up 100,000 simultaneous connections over a 56k modem. And even on dedicated lines, there’s a problem getting data into and out of a network fast enough, particularly if there’s streaming video or audio on the site: the bandwidth consumption of these applications, which require far more consistent streams of traffic than their HTTP counterparts, is phenomenal if any quality is to be attained.

But sometimes, the bandwidth problem is caused by the ISP rather than solved by it, maintains Andy Crosby. “An ISP will supply with what it can get away with, rather than what’s actually purchased because it’s actually fairly difficult for a web site designer to test the bandwidth of its connection. I had one client who had purchased a 2Mb pipe. We tested it and he was getting 500k. We phoned the ISP and they said they’d see if they could fix it. A couple of minutes later, they were getting 2Mb.”

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