The CDN is a content delivery network where by you would have your websites static content served via the shortest route available thus decreasing web page loading time and increasing responsiveness.
Let’s say we have a server located in France and this is our web server. When someone visits your website, your server will provide your visitors with the content.
If the visitors are visiting from France or in Europe the websites will load fairly fast as its geographically close to your server location. If the visitors are visiting from America or Asia the data regarding your website has to travel further before the visitor sees the web content. This means that these visitors will take longer to load your web content.
With the use of the CDN the static content will be served locally on the geographic location’s node. Let’s say we have a website with content that keeps changing such as a breaking news and every few minutes the page is being updated with new information.
If the server is based in France and the current visitors are based in Europe, the loading speed is 10 seconds. Visitors in America and Asia would load the same content in 15 seconds. The CDN would keep a copy of the web page content to the CDN network on the American node and Asia’s node. Subsequent visitors will get the data served from this node, their loading speed would be 8 seconds and it would only request the data difference from the original website to its cached version. This would drastically reduce the loading speed of the web page even through the visitor is geographically distant from the source server.
The numbers used are only examples of the CDN there would be a number of factors which would determine the performance of the CDN.
There are 2 types of CDN, one type is for web storage where by you share large volumes of data such as images or videos. Typically multimedia would slow down the loading speed of an website as it takes time to load the large content. The web storage CDN will cache the multimedia across multiple locations thus ensuring the data loads in the fastest time frame as possible.
The other type of CDN is for the whole website itself rather than just having CDN, you would store everything on the website to the CDN cache.