What is a CDN? An Easy Overview(2021)

Ajay Ohri


What is a CDN? CDN or the content delivery network refers to a group of servers that are distributed geographically and which work in sync to offer quick internet content delivery.

The CDN allows quick asset transfer that is needed to load the content on the internet. These include the JavaScript files, HTML pages, images, and videos, etc. The CDN networks have seen a growth in their popularity, and the majority of the web traffic today is served with the CDN. A CDN that is configured properly also protects the website from malicious attacks.

The CDN meaning is not the same as the web host. The CDN does not host any content and this is why it cannot replace the proper hosting of a web. However, it does help the cached content at the edge of the network that improves the website’s performance. Many websites are not capable of meeting their performance needs through the traditional services of hosting, which is why they opt for the CDN.

Using the cache to reduce the bandwidth of hosting, CDN helps to prevent any kind of interruption in the services and improves security too. CDN also helps to solve some pain points that come with the traditional methods of web hosting.

  1. What is a CDN?
  2. How does a CDN work?
  3. Benefits of using a CDN

1) What is a CDN?

So what is a CDN? The content delivery network or CDN is a platform of servers that are highly distributed. They help to minimise the delay in loading the content on the web page. This it does by reducing the physical distance between the user and the server. It is this that lets you get the same content quality from anywhere in the world without any slowdown of the loading time.

If there was no CDN, then the content origin servers would have to respond to every single request of the end-user which would result in significant traffic. This would decrease the speed and lead to chances of failure if there is a peak in traffic or in case the load is persistent.

The CDN responds to the request of the end-user in the origin place and in the close network and physical proximity of the end-user. The CDN helps to offload the traffic from the contents server which in turn improves the experience of the web, and this benefits the end-user and the provider of the content.

2) How does a CDN work?

The majority of traffic on the internet is served with CDN or the content delivery network. The CDN helps to reduce latency which is the time delay in submitting a request for any web page and the web page to fully load on the device. This it does by reducing the physical distance that the users request needs to travel.

CDN has a cache version of the website content in various geographical locations across the world. This is known as the points of presence (PoPs).

The PoPs have their own caching server and this is responsible to deliver the content to the location of the user. The user agent is basically the device that runs the web browsers and makes a request for the content needed to render the web page as is needed. Every request for the content will lead the end-user to get mapped to a CDN server that is optimally located.

The server then responds to the cached version of the files requested. If the file does not get located then it looks for the content on other servers in the CDN platform and then sends the response to the user at the end. If the content is not available or is stale, then the CDN will give a request proxy to the original server and then store the fetched content to the server for any future requests.

The website content delivery is the common use of the CDN, but it is not the only kind of content that the CDN delivers. The CDN can deliver many varieties of content like audio streams, HD and 4K quality videos, games and apps, and many more. Basically, any data that is capable of being digitised can be delivered through the CDN form.

3) Benefits of using a CDN

There are many benefits of CDN to use which depend on the size and the needs of the property of the internet. However, the primary benefit of CDN users can be broken down into four major components.

  • It improves the load time of the website. This is done by distributing the content close to the website visitors by using the CDN server nearby. The visitor gets to experience a fast page load time. CDN thus reduces the bounce rate and increases the time that people spend on a website.
  • It reduces the cost of bandwidth. The main expense for a website is the cost of bandwidth consumption. CDN makes use of optimization and caching through which it is capable of reducing the data amount that can be provided by an origin server which reduces the cost for the website owner.
  • CDN increases the availability of the content and also its redundancy. Because of large amounts of hardware and traffic, the normal website function can be interrupted. CDN with its wide distribution network can handle a lot of traffic and withstand the failure of hardware better than many of the origin servers.
  • CDN can help to improve website security by offering various kinds of optimisations.


You now understand what is a CDN. CDN is an easy way to increase website speed and also lowers its latency. CDN thus offers efficient, fast, and secure content delivery to users from across the world. CDN helps to deliver content faster, and with the visitors’ attention growing shorter by the day, CDN makes it possible to hold on to the visitor for long. With businesses going online and coming together to connect, shop, and share, there is a range of user needs. These include content delivery of various types, adjusting the content for various devices, and securing the data and the end users’ presence online. The CDN lets the business to overcome these various challenges of delivery.

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