What Is A CDN?

Date First Published: 18th April 2022

Topic: Computer Networking

Subtopic: Network Services

Article Type: Computer Terms & Definitions

Difficulty: Medium

Difficulty Level: 5/10

CONTENTS

Benefits Of CDNs
Examples Of CDNs
History

Learn more about what CDN is in this article.

Short for a content delivery network, a CDN is a group of servers distributed in different geographical locations that are designed to provide fast delivery of internet content, such as HTML pages, stylesheets, JavaScript files, images, videos, and other content by caching as well as protecting websites against cyberattacks, such as DDoS attacks. Small CDNs are located in a single country and large CDNs are located in different data centres all around the world.

Over half of internet traffic is delivered by CDNs. Popular websites, such as Amazon, Facebook, and Netflix use CDNs. CDNs are also invisible. Users will never know that a website is using a CDN unless they perform a WHOIS lookup.

Note:

CDNs are not the same as web hosts, since they do not actually host the website content. CDNs are networks of servers that are combined together to deliver content quickly and securely and improve the performance of a website. Most websites that struggle to fulfil their needs by web hosting services opt for CDNs.

Benefits Of CDNs

They improve website loading times – Since CDNs cache website files, they overall reduce the amount of bandwidth used for a website. Most web hosts, especially free ones provide users with a limited amount of bandwidth per month. CDNs have the ability to reduce the amount of data that a web server must provide due to caching. As a result, faster website loading times mean that more people will visit it. In addition, hardware enhancements, such as the use of solid-state drives helps data reach the users quicker.

Note:

Cache temporarily stores a copy of resources, such as files in order to make pages load quicker.

They improve website security – CDNs, such as Cloudflare provide protection for websites against DDoS attacks by hiding the real IP address of the server, preventing it from being targeted, detecting unusual traffic spikes from certain IP addresses, and blocking IP addresses. In addition, they can also provide TLS/SSL certificates to encrypt communications between the web server and device.
They reduce latency. Since CDNs are globally distributed, they reduce the distance between the users and website resources. CDNs enable users to connect to a geographically closer data centre rather than wherever the web server of a website is located and since they automatically choose the best server for each user, it is unnecessary for users to manually choose the best location. For example, visitors in the United Kingdom requesting to view content that is hosted on a server located in the United States will have to deal with higher latency than if the CDN stored the content on a United Kingdom PoP (Point of Presence), since the requests will have to travel across the Atlantic Ocean.

Examples Of CDNs

Common CDNs include:

History

CDNs were introduced in the late 1990s with the aim of reducing bottlenecks on the internet. Over a period of time, the size, features, and technology of CDNs have grown. The first CDN was launched by Akamai in 1998.

More than 3000 companies began to use CDNs by 2004 and in 2008, Amazon launched their CDN, called AWS CloudFront. A major CDN that is used by millions of websites called Cloudflare was founded in September 2010.