Content Delivery Networks
A Content Delivery Network (CDN) allows content to be delivered from alternative physical locations. By using the geographical location of the user, a piece of content can be delivered via a server that resides in their country.
There are immediate benefits. For example, take an image that is used in a web page that is being viewed by someone in London. It will arrive far more quickly if it is being delivered by a server in London than if it has to come from a server on the west coast of the USA such as in California. Not only that, but the traffic cost will be substantially lower.
For example, the Abraxor website has a Content Delivery Network attached. This reduces lag times from around 140ms to less than 3ms for users in London if the content is placed on our Internet Edge connection. Not only that but loading up a sample image of around 36KB has been reduced from anywhere between 1 and 1.8 seconds down to around 0.2 seconds.
There are several ways that CDNs are implemented. Often this will involve giving servers a virtual IP that allows the request to be routed to the closest physical server.
- Akamai Technologies - one of the oldest providers
- Amazon CloudFront - a new player building on their success in other areas of their technology infrastructure
- Level 3 Communications - one of the largest communications and Internet backbones in the world