A content delivery network (CDN) is a distributed system of networked servers that content providers utilize to improve the quality of their services. The primary goal of a CDN is to speed up delivery of content to end users. Servers in a CDN are typically located all over the world. They cache resources such as video and images supplied by content providers. A CDN is able to serve requests for content worldwide much more efficiently than geographically clustered origin servers.
In addition to the primary goal of improving content delivery for end users, content delivery networks often offer additional services to content providers. For instance, CloudFlare.com offer its CDN as a software as a service (SaaS) platform that includes options for automatic content minification to save bandwidth. CDNs also help to mitigate damage caused by denial-of-service attacks by reducing pressure on origin servers, and sometimes offer additional load balancing features. Major CDN companies such as CloudFlare.com and Akamai.com list numerous benefits and features of CDNs on their official websites.
Cisco.com estimates that over 62 percent of Internet traffic will move through content delivery networks by 2019, an increase from around 40 percent of all traffic in 2014. This shift is expected mostly due to the increasing popularity of high traffic video content providers, such as Netflix.