The Hostway Blog

Host Location Series Part 5: The benefits of CDN for website speed

By Gail Seymour

As Internet speeds increase, visitor patience decreases. Accustomed to broadband connections, we expect a site to come up on our browser faster.

The Importance of Page Download Speeds

In 2000, a survey by Bouch, Kuchinsky, and Bhatti "Quality is in the Eye of the Beholder: Meeting Users' Requirements for Internet Quality of Service" suggested the average visitor would wait 8 to 10 seconds for a site to load before hitting the back button and looking elsewhere.

By 2006, another survey commissioned by Akamai Technologies "Retail Web Site Performance: Consumer Reaction to a Poor Online Shopping Experience" suggested this had dropped to around 6 seconds. "A study on tolerable waiting time: How long are Web users willing to wait?" by Fiona Nah even suggested a 2-second threshold.

Websiteoptimization.com notes, “Slow Web pages lower perceived credibility . . . and quality,” whereas, “Faster Web sites are actually perceived to be more interesting . . . and attractive.” Longer load times also reduce sales and profits. In 2007, tests on Amazon.com showed a 1% decrease in sales for every 100ms increase in page load time--that’s 10% for every second.

In light of these figures, it’s easy to see how important the location of a Web server becomes. While it’s a straightforward issue to address if you are a locally focused business, the nature of the Internet means the majority of Web sites have an international audience.

Improving download speeds with a CDN

As we discussed in previous articles in this series, when a user visits your site, they generate a request for information from your server. This request is passed through a series of routers until one is found that recognizes the IP address of your server, then forwarded through yet more “hops” to reach your machine. We discussed in this context the importance of hosting your website close to the Internet backbone to minimize the number of hops required to serve your site to users.

A CDN takes this idea further, by caching your data on a series of connected servers strategically located around the world and effectively eliminates some of the hops required to reach your site from different countries.

It’s a bit like software download sites that offer you a choice of server location so you can choose the nearest to you, only the CDN calculates the quickest route and serves the content without the user having to make a conscious decision.

CDNs don’t simply make decisions based on location, though. They monitor the network speeds and availability of multiple connections and calculate the most efficient delivery route in real time. They might also serve multiple files included in your page, such as images, audio and video files, from different servers simultaneously to increase speed.

Other Advantages of CDNs

Besides reduced download times due to shorter delivery routes, CDNs offer other advantages:

  • Because your data is housed on several distributed platforms, it’s less vulnerable to downtime due to power outages, server failures, or anything else. If one server is down, or experiencing heavy traffic, requests are simply rerouted to the next available server automatically.
  • The network of servers has access to vastly increased bandwidth, and so can process unexpected bursts of traffic. You may have to ask your Web host to increase your allowances, but your site’s capacity can be increased with a simple request. In addition, unlike a server upgrade on a standard hosting platform, the increase may be temporary, meaning you have to pay only for the increased resources when you need them, rather than committing to a more expensive package than you need most of the time.

There are other ways to optimize download speeds, such as removing nonessential elements and limiting scripting and multimedia content. Often, it’s the functionality of the scripted elements of the site, or the interactive multimedia, that attracts your visitors in the first place, though. In which case, removing them would do more harm than good.

If your website is media heavy, carries a large ecommerce catalog, or offers software downloads, and is international in scope, you might consider using a Content Delivery Network (CDN).