CDN: The Definition and How it Works

Content Delivery Network (CDN) is essential for all modern-day websites and applications. The content that you access via your phone or laptop on any website or app, images, videos, or any other kind of content, is likely to be delivered to you using CDN solutions. As you know, the internet is a collection of networks. 

There are web servers deployed in these networks that cater to the users’ requests. But, when a web server is located in one single location, it becomes challenging to handle multiple workloads, which affects the website’s performance. 

Hence, to stabilize the load on infrastructures and provide content faster to the end-users, CDNs are deployed in data centres. Continue reading to have a better idea of CDN and how it works.

 CDN: The Theoretical Definition

Content Delivery Network or CDN is a group of geographically distributed servers deployed at various data centres to speed up web content delivery. The main aim of CDNs is to bring the data closer to users’ locations and provide faster performance, high availability, and security to websites distributing their content via it. 

CDNs are the backbone of businesses that attract massive web traffic. Video streaming platforms like Netflix, e-commerce giants like Amazon, and social media giants like Facebook are prominent businesses that rely on CDN services to deliver their content to the end-users. 

Why is CDN needed?

Here’s an example to further give you better clarity on why you need CDN. Read on!

Suppose you own an eCommerce store in the US. 

You have a fantastic-looking website and have hosted it on a server located on the east coast of the US. All your files, textual content, javascript files, images, everything that loads on your website comes from your east coast server. 

One of your customers sits on the west coast of the US; when he browses through your website, every request from the users’ device goes to your server on the west, which is approximately 2000 miles away and fetches the data. 

Don’t you think this will take a few hundred milliseconds to load your website after all distance between the server and the user is the critical factor determining your page load time? Remember, Google Analytics says a website that takes more than two milliseconds to load negatively impacts the site’s user experience and, thus, the conversion rate.

Businesses that implement CDNs can gain in many ways, that include:

  • Faster content loading and response time in delivering content to users
  • CDN security, privacy, and integrity
  • Higher scalability and availability (as CDNs can integrate with cloud models)
  • Minimizes redundancy in content
  • Enhanced User experience (UX) 

How does CDN work?

As mentioned above, CDN is a geographically distributed network of servers; each is called a Point of Presence or PoP or an edge server. PoPs are responsible for storing and delivering your website’s content. 

Instead of fetching your site’s resources directly from your website server, CDN’s PoPs are used to deliver the data to the users directly. Dynamically, CDN management software calculates the PoP that is closest to the user and thus requests the content from the closest one.

Further, the requested PoP server communicates with the primary server to deliver new content that has not been previously cached to the user. Organizations opt for reliable CDN solutions to minimize the distance travelled by their content and provide faster performance, optimize bandwidth, and minimize timeout, jitter, and latency.

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