CDN name is Content Delivery Network, namely, content distribution networks. The idea is likely to affect as much as possible to avoid bottlenecks and link data transmission speed and stability of the Internet that allows faster transmission of content , more stable. By placing a layer of intelligence throughout the network node server constituted the basis of the existing Internet virtual network , CDN systems in real time based on the connection , network traffic and load status of each node and the user's distance and response time comprehensive information on the user's request to redirect the user from the nearest service node. Its purpose is to enable users to get close to the desired content , Internet network congestion to resolve the situation , improve the response speed user access to the site.

Content Delivery Network (CDN) is a new web content service system , and the IP network construction, and efficiency requirements of the application to access the contents , the order and content of the quality requirements and provide content distribution and service . From a broader perspective , CDN represents a network built based on high quality, high efficiency , with a distinct order of the network application network service model .

Simply stated , the content delivery network (CDN) is a strategic move by the overall system , including distributed storage , load balancing, redirection and content management four elements of network requests , and content management and overall network traffic management ( Traffic Management) is the core of CDN . By determining user proximity and server load , CDN ensure that the content in an extremely efficient way to provide services to the user's request .

Overall, the content service based cache server , also known as proxy cache (Surrogate), which is located at the network edge , away from the user just " hop " (Single Hop) away. Meanwhile, the proxy cache content provider origin server ( usually located in the CDN service provider's data center ) a transparent mirror . This architecture enables CDN service providers to represent their clients, that content providers to provide the best possible end- user experience, and these users will not be tolerated any request response time delays .

CDN popular understanding is site acceleration , CPU load balancing can solve cross-operator , cross-regional , server load capacity is too low , the bandwidth is too small and so slow to bring the site to open other issues .

1 , an enterprise web server in Beijing , is a telecommunications operator , in the Guangdong Unicom users to access the corporate website , as trans-regional , inter-carrier reason , the site will open speed slower than Beijing local telecommunications access speeds many customers easily lead to the enterprise customer churn.

2 , a server site performance is relatively poor, with limited carrying capacity, sometimes faced with bursty traffic , overwhelmed , a direct result of a server crash , the site open, especially during the festive season electricity supplier website , because this situation can not open website , accounting for the loss of sales in vain are rising to 60 %.

3 , small businesses hire virtual hosts , because with several sites share a single server , each site of the limited bandwidth , the bandwidth is too small often leads to flow a little more than one website open very slow speed , even open.