What is CDN ?

Website speed and load times can make or break the overall user experience. Data suggests that 25% of visitors abandon websites that take more than 4 seconds to load and that a 1-second delay reduces customer satisfaction by 16%! This is where CDN comes in. Created to be a transparent backbone of the internet, CDN improves website load times and provides faster content delivery.

Regardless of our awareness of it, we are constantly interacting with CDNs, from searches to online shopping, watching YouTube videos and consuming social media. Combined with its other powerful benefits, it has earned itself an undeniable place in the web and business ecosystem.

Read on to know more.

CDN or Content Delivery Network is a highly distributed group of servers that helps minimize delays in loading web pages and ensures faster delivery of internet content. It enables users across the globe to consume internet content at the same high quality without slow loading times.

CDN allows for seamless, quick, reliable, and secure transfer of assets necessary to load internet content, be it – HTML pages, JavaScript files, stylesheets, images, videos, live streams, 4K videos, software downloads, etc. Regardless of the type of content being consumed over the internet, the chances of a content delivery network being behind every character of text, every pixel of an image and every movie frame are high. A majority of web traffic is served through CDNs, including global majors like Facebook, Amazon, and Netflix.

Goal of Content Delivery Networks

The main purpose of content delivery networks is to reduce latency. Latency refers to the delay that happens between submitting a request for a webpage and the webpage fully loading on the user’s device, displaying the requested content. It is measured in milliseconds and is the total time taken for a site visitor to connect to the webserver, their request to be processed and for the server to start sending the data requested.

Latency is affected by many factors which are often specific to the website. However, one factor that affects latency across the board is the physical distance between the web server and the user. The CDN’s goal is to shorten this physical distance and improve page load times and website performance.

How does a CDN work?

At the core of content delivery networks is caching. Caching is the process of storing copies of content/ files in caching servers at multiple geographical locations on the network edge called Points of Presence (PoPs). Each PoP has multiple caching servers, and the PoP is responsible for delivering content to visitors within its proximity.

Each time a visitor makes a request for content, an optimally located server will be mapped and their request routed to that caching server. The caching server responds with the cached version of the webpage/ content/ files. If the files cannot be located, other servers in the CDN-platform would be searched before sending a response to the visitor. If the content is not cached, the platform acts as a request proxy to the original server and stores the fetched content for future requests.

Without a CDN, the visitor requests would be directed to the origin server itself. If there is a sudden traffic spike, the bandwidth could be completely used up and the website may crash or become unavailable.

How is it different from a Web Host?  

The CDN does not host content and cannot replace the need for proper web hosting but helps in relieving some of the pain points of traditional hosting, especially with respect to website performance. By caching content at the network edge, the CDN reduces hosting bandwidth, enhances security, and prevents interruptions in service.

Benefits of using a CDN

Increase website speed

Since web visitors are serviced by the PoP closest to their location, CDN improves website load times. With faster delivery of requested content, websites improve their user experience and minimize bounce rates.

Reduce bandwidth costs

CDN reduces the need for the origin server to provide data. Given that the bandwidth consumption cost of website hosting is a primary expense for websites, website owners save significantly by onboarding a CDN service.

Improve content availability 

Given their distributed nature and built-in redundancies, CDNs are better equipped to handle sudden traffic surges and hardware failure better than origin servers.

Strengthen website security

By ensuring that general web traffic does not directly access websites, CDNs prevent DDoS and other website attacks. When combined with a robust Web Application Firewall (WAF) placed at the network perimeter, it can help fortify website security.


Given its criticality, businesses must invest in CDN (unless they have a strictly localized website with users located in the same location as the origin server). Choose the right CDN providers to ensure that you have an always-available, high-performing, and secure website!