← Back to Glossary

What is a Content Delivery Network (CDN)?

by Iwan Price-Evans on Web Application Firewall • May 13, 2022

A content delivery network (CDN) is a type of distributed computing system that allows multiple computers to work together to serve web requests. A CDN replicates and caches static data in multiple locations and serves data from the server closest to the client.

What Are The Advantages Of Having A CDN?

A CDN is an essential part of any modern website because it speeds up the loading times of websites. Serving content from the server located nearest the client reduces latency because latency is related to geographic distance.

Using a CDN means that visitors will see your site load faster, which makes them more likely to stay on your site longer.

What Types Of Content Can A CDN Cache?

CDNs are useful for caching static content – that means content that does not need to be personalized to the client.

Static content includes images, audio and video files, static page HTML, CSS files, and JavaScript files.

What Are Some Things That Should Not Be Cacheable?

There are some things that should not be cached because they are dynamic and constantly changing. These include databases, user account information, and pages with A/B or multivariate testing enabled. If these files are cached, then they will not update with changes made to the original source. This means that the cached version of the file will never reflect the latest version of the file.

What Are Some Other Ways To Speed Up Page Load Times?

One of the biggest benefits of using a CDN is speed. Caching static content such as HTML, CSS, JavaScript, and image files reduces the load times of websites. In addition, when a user requests a resource, the CDN server closest to the user will respond first. This speeds up the process of delivering the requested resource.

You can also speed up page load times by compressing images, combining CSS and script files, and offloading intensive tasks like SSL termination. You can use a web accelerator to do this automatically.