Content delivery networks (CDNs)

A content delivery network (CDN) is a type of cache that stores copies of digital files in multiple geographic locations. The aim is to reduce latency, improve performance, and increase availability by serving files from the nearest servers to the end user.

CDNs are implemented as geographically-distributed networks of servers. They are widely used to deliver static web content such as HTML pages, JavaScript bundles, stylesheets, images, and video. When a user requests such content from a website, a CDN will redirect the request to the nearest server in its network, reducing latency (download times) for a better user experience.

There are two types of CDNs: pull-based and push-based. Pull-based CDNs pull objects out of object storage only when those objects are requested and the existing cache, if any, is stale. Push-based CDNs are pre-populated with objects from the origin server.