What is a CDN?

A Content Delivery Network (CDN) is a network of servers that help speed up your website by caching essential files and making them available locally to visitors all around the world.

Besides speeding up your site, a CDN can also increase its security, stability, and reliability. In this article, we’ll walk you through how a CDN works and why you should consider one for your site.

How does a CDN work?

To understand a CDN’s function, keep in mind that it takes time to send your website over long distances. If your server is located far away from a visitor, the site will load slower than for a visitor in the server’s local area. A CDN solves this problem by moving website data closer to all web users.

The network of servers that make up a CDN are specifically set up to quickly send data to web users. The CDN itself sits between visitors and websites to reduce the time they need to wait for a website to load.

Nodes in the CDN are spread all over the world, meaning that all web users have a node in their vicinity. Each node can then quickly deliver the most important parts of your website. As an example, this means that a user located in the US can retrieve a website from a local node in North America instead of waiting for it to load from a server in Europe.

Let’s break down how a CDN works, step by step:

1. A person in Los Angeles visits your website, which is located on a UK server.
2. The visitor’s browser sends a request to the website server.
3. The server responds by sending all the files, visuals, and texts associated with the site to the visitor’s computer. The distance results in the site taking 3.2 seconds to load.
4. At the same time, a copy of the files from the website server is sent and cached by a local CDN node in Los Angeles.
5. Now a new visitor in San Francisco arrives at your site. Instead of again having to load the files from your server in the UK, they are downloaded from the local CDN node in Los Angeles. The website now loads in 1.3 seconds for this visitor.

Why you need a CDN

According to a study from 2020, a website that loads even 0.1 seconds faster can see positive results in its number of page views and conversion rate.

Many websites take three, five, or more seconds to load, and there are many different reasons a website may be slow. It may be that it gets too much traffic, is not optimised, or because its server is too far from its visitors. A good CDN can solve all these issues to improve your website. Here we share some of the biggest benefits of using a CDN.

Helps manage traffic peaks

Traffic to your website may go up and down and buying an expensive hosting package to handle traffic peaks that only occur a few times a year can end up being a waste of money. A CDN can help your website deliver images and big files to relieve the load on your website on the most intense days. With a CDN, you can host a big sale on your online store with neither your site crashing nor having to pay extra for hosting.

Makes your website faster

A CDN can immediately speed up your website by sending files from a server that is physically closer to your visitors. Some CDN services also optimise your website to make it faster. They can, for example, offer compression of images and use new web technologies to make server connections more efficient.

Improves security

A CDN can act as a gatekeeper between your visitors and your website. Attacks and harmful behaviour can be stopped before they reach your website. A CDN can, for example, stop criminals from leaving spam comments or damaging your website in other ways.

Protects against DDoS attacks

A Distributed Denial of Service (DDoS) attack is a way for criminals to take websites offline. These types of attacks involve criminal server networks sending out large amounts of traffic to a website until its server becomes overloaded and goes offline. DDoS attacks can be used to punish website owners or as a means of extortion.

Since a CDN is a network with large resources, it can handle massive traffic. It makes it possible to effectively block a DDoS attack and ensure a website is available even in the most demanding situations.

Keeps your website online

Besides coordinated attacks, websites can go offline for many other reasons. For example, your hosting provider could stop working for a short time. In this situation, a CDN can display a saved version of your website. This saved version may have limited functionality and may go offline through longer interruptions. Regardless, it still helps provide your visitors with a more reliable experience and gives you reassurance that your website will stay up through short interruptions of service.

Optimises with new web features

Besides saving files from your website to deliver to visitors, a CDN can also change files and optimise how visitors’ browsers receive your website. For example, some CDN services can compress images from your website, or create special mobile-first pages that load faster. These changes are made to the files that are saved in a CDN, meaning you don’t need to make changes to your website yourself. However, it is worth noting that these optimisation features often cost extra since they go beyond what a CDN typically offers.

Does every website need a CDN?

A CDN is not a requirement for running a fast and secure website. If you have a simple website that lacks large images, doesn’t get a large volume of visitors, and mainly receives traffic from local visitors, you most likely don’t need a CDN. While a CDN is always beneficial, it’s not necessary to pay for this additional service if you only have basic needs and a low-traffic site.

Get started with a CDN

The easiest way to get started is to use a CDN that is included in your hosting package. At one.com, we offer a free CDN for all WordPress users. With our Performance Cache plugin, you can manage and clear the saved files of your CDN right from your WordPress dashboard and get the benefits of a worldwide CDN service.

If you want to use a third-party CDN for your website, you will need to manually make changes to some settings on your domain. These changes can be difficult to make, but if you have a hosting provider with good customer service, they can usually help you with any questions.

There are CDN services that are free of charge. These usually have limited functionality and performance but also offer paid versions. A free example is Cloudflare CDN. Examples of paid CDN services are Bunny CDN and Keycdn.

You can choose a CDN service and test it for a short period. If you want to replace it, it is often as easy as activating it in the first place. You only need to change some settings for your domain, and you rarely need to make any changes to your website. You can find instructions on how to activate your CDN at your CDN provider.

To summarise, a CDN can make your website faster, more secure, and more reliable. A CDN is especially important for large websites with varying traffic volumes, where the website must always be online. We hope this article has helped you understand if you need a CDN and how you can get started with one.