A content delivery network (CDN), in its simplest terms, is a collection of website servers that are deployed across multiple locations. When a user visits your website, the content delivery network will determine which of these servers will deliver content to them fastest. The overall goal is to lessen the strain on your main website server and allow faster performance for all of your users.

What is Stored on a Content Delivery Network?

There are a number of elements to any given website—from raw hypertext and scripts to rich multimedia and dynamic database data. With the explosion in video, Flash elements, online gaming and streaming media, the bandwidth demands of large, multimedia-centric websites have grown exponentially. This is the type of content that is typically offloaded from the core website server and placed on a content delivery network. The content stored on a content delivery network includes HTML, Flash, music files, images, PDFs, videos, podcasts and other items that tend to consume a vast amount of bandwidth.

Content delivery networks are not typically able to store dynamic database results. This information will usually be kept on the central website server.

What are the Benefits of a Content Delivery Network?

With a content delivery network, all of your high bandwidth files and media is mirrored on a number of different servers. This allows faster delivery than if you had a single website server on a single network backbone. For instance, if your network backbone had a 10 GB per second capacity, any requests that exceed this speed would have to queued up or lost. For each server you add, you can increase your overall network speed. For example, with a CDN, you could have ten servers, each on a network backbone with 10 GB per second, which would allow you to deliver content to the entire Internet at 100 GB per second.

Content delivery networks also introduce greater reliability for your content. With a single website server, one denial of service attack, power outage or other technical issue can bring your entire site down. But with a content delivery network, if one of your servers fails, the others can pick up the slack.

What are the Drawbacks of a Content Delivery Network?

As with all advanced and premium website server services, the primary drawback with a content delivery network is price. For most websites and personal blogs, a content delivery network is prohibitively expensive. The benefits simply don’t justify the costs. But for very large sites that rely on delivering high quality, on demand media to millions of users, a content delivery network is an absolute must. For example, YouTube, which delivers over 100 million videos a day, locates its most popular content on a content delivery network.

Summary

For websites that host high bandwidth content, a content delivery network can help them reduce server load, increase speed and performance and ensure reliability. Content delivery networks are inherently expensive, though—so much so that it’d be imprudent to give a ballpark figure. To get an idea of whether a CDN is worth your money, you should contact a few different CDN hosts and have them make an offer. But also make sure you weigh out your options against a dedicated server, cloud hosting and other website server solutions as well.