Benefits of using a CDN

Content delivery networks (CDNs) are collections of web servers that are distributed across multiple locations around the world in order to deliver content more efficiently to users. The goal of a CDN is to serve content to end-users with a high availability and high performance.

When a user makes a request to your website that is hosted in, say, New York, while they are based in Germany, the internet tubes must connect from the user’s location in Germany to the data center in New York. This means your users will need to make a round trip across the world in order to retrieve a file from your server.

Since static files such as images, JavaScript and CSS don’t change very often, there is no reason that they can’t be served to the user by another server that is geographically closer to them. It’s a shorter distance to travel, and this means quicker response times.

The benefit of using a CDN extend far beyond just faster response times; using a CDN additionally reduces the amount of bandwidth that is consumed by your website. It also increases the number of files that a browse can download in parallel. Most browsers only allow you to download three or four files at a time from one domain. Using a CDN will enable the user’s browser to download more files in parallel, increasing response time.

The most popular commercial CDNs are: Amazon Cloudfront, Rackspace (using Akamai network) and Windows Azure.