CDN or content delivery network is a selection of geographically distributed servers, whose use offers the ability to speed the delivery of web content by taking it closer to the user.
CDNs were created to allow for the quick loading of internet content by caching content on a server closer to the user, including text, graphics, scripts, and media files to software downloads, documents, portals, eCommerce, live streaming media, on-demand video streaming media, and social media sites.
CDNs can also provide websites with increased protection against malicious attacks and security concerns like distributed denial-of-service (DDoS) attacks.
It is important to remember that a CDN does not host content and cannot replace the requirement for actual hosting, it does help cache content at the network edge, which improves website performance. With many websites being accessed globally, investing in a CDN can help improve the user experience greatly, over traditional hosting services.