CDN Content Delivery Network内容分发网络

A content delivery network or content
distribution network (CDN)
is a globally distributed network of proxy servers deployed
in multiple data centers.
The goal of a CDN is to serve content to end-users with high availability and high performance. CDNs serve a large fraction of the Internet content today, including web objects (text, graphics and scripts), downloadable objects (media files, software, documents),
applications (e-commerce, portals), live streaming media,
on-demand streaming media, and social networks.

The term CDN means many things to different people and is an umbrella term that covers a lot of different types of content delivery services. Video streaming, software downloads, web and mobile content acceleration, licensed/managed CDN, transparent caching,
and services to measure CDN performance, load balancing, multi-CDN switching and analytics and cloud intelligence. It’s a complex ecosystem with a lot of vendors both large and small and some CDN vendors cross over into other industries like security and WAN
optimization.[1]

Content owners such as media companies and e-commerce vendors pay CDN operators to deliver their content to their end-users. In turn, a CDN pays ISPs, carriers, and network operators for hosting its servers in their data centers.