A content delivery network (CDN) is a group of geographically distributed servers that speed up the delivery of web content by bringing it closer to where users are. Data centers across the globe use caching, a process that temporarily stores copies of files, so that you can access internet content from a web-enabled device or browser more quickly through a server near you. CDNs cache content like web pages, images, and video in proxy servers near to your physical location. This allows you to do things like watch a movie, download software, check your bank balance, post on social media, or make purchases, without having to wait for content to load.
You could think of a CDN like an ATM. Having a cash machine on practically every corner makes it fast and efficient to get money. There’s no wait time in long bank lines, and the ATMs are placed in many convenient locations for immediate access.
CDN services were created to solve the problem of network congestion caused by delivering rich web content, such as graphics and video over the internet — much like a traffic jam. Getting content from centrally located servers to individual users simply took too long. CDNs have now grown to include everything from 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 actors and security concerns like distributed denial-of-service (DDoS) attacks.