CDN: content distribution network or content delivery network, primarily for web site provides access to accelerate function, make content transmission faster and more stable

IDC: Internet data center, hereinafter referred to as IDC room, for each type of site, enterprises, media provide large-scale, high quality, safe and reliable specialized server hosting, server rental, network bandwidth and other services, the use of the existing Internet communication lines, bandwidth resources, to establish a standardized telecom professional computer room environment, for the enterprise, the government provides the server hosting, rent and related value-added full-service,

IDC can be said to be the basis of CDN, without IDC is no CDN

For now IDC in China has eight nodes, and a few spare node, these are the core backbone network, branch, through these nodes in each region was set up by three carriers (telecom, unicom, mobile),

Some relatively small company self-built room, these room rack, bandwidth, lines, are all related to the performance of the machine room

The level of Internet data center is divided into A, B and C

A level of fault tolerance type
Basically, the banking system by grade A standard room much do
B
Government departments, large enterprises according to the customer request design according to class B
Class C
Institutions and education department according to the relationship of class C design CDN and IDC