You wake up one day intending to buy a bottle of Bordeaux, the famous French wine, to celebrate an important anniversary. Wherever you live, you will certainly not drive to Bordeaux to get it, but you will go to the closest wine shop. The CDN is the network of the local stores which provide web content to millions of people. And like a bottle of wine, if the web content is available nearby, it will be faster delivered to the customer.
A CDN’s goal is, therefore, to minimize the physical distance between the user and the website content in order to reduce the latency, the time frame between the page loading request and its show on the screen. This happens thanks to multiple and geographically distributed PoPs (Points of Presence, the single local shops) which store part of the website’s main server content, especially the static one.
Let’s a make a simple example.
CDN’s popularity is quickly spreading. Any time we go on the internet, we deal with their transparent presence: nowadays, in fact, more than 50% of the websites are using them, including Facebook, Netflix and Amazon.
Do I need a CDN?
Your website needs a Content Delivery Network if its web audience is located in many different countries. Without a CDN, the main server (called origin server) must respond to every single user interaction with the website. This would create a significant traffic to the origin and, therefore, loading times and chances for failures would be exponentially higher.