CDN — Content Delivery Network

What is a Content Delivery Network (CDN)?

A Content Delivery Network (CDN) is a system of multiple servers and storage (CDN nodes) that accelerates the delivery of Web pages, audio, video and other Internet-based content to users. The CDN nodes replicate the content provider's files in servers, called "caching servers" or "edge servers," located in geographically dispersed data centers. Most CDNs are third-party services; however, large companies may develop their own "enterprise CDN". As of 2018, Akamai, Google, Cloudflare, Microsoft, Rackspace, Amazon and Limelight are among the largest third party CDN providers.

CDN nodes are installed in various locations to assist each other in fulfilling end-user content requests to optimize the service delivery process. The number of nodes participating in a CDN varies with respect to the network architecture and bandwidth required. Strategically placed edge servers lower the delivery time and decrease load on public and private peers, backbones and interconnects, while satisfying content requests at the edge of the network to reduce content access latency.