The full name of CDN is Content Delivery Network. The basic idea of CDN is as much as possible to avoid the bottlenecks and obstacles being possibly affecting the speed and stability of the data transmission in the internet, so that the data transmission can become faster and more stable. Through placing node servers throughout the network, a layer of intelligent virtual network can be formed on the basis of the existing internet. Through the layer of intelligent virtual network, CDN system can redirect the users’ request to the nearest serve node in a real-time way, according to a pack of comprehensive information including the network flow and the connections of each nodes, load conditions, user distance and response time. The purpose is to let users obtain the required content in the nearest way, solve the status of the Internet network congestion, and improve the response speed of the users’ access to the website.

Building CDN can bring the following advantages:

（1）Local Cache accelerates. This increases the access speed of the enterprise sites (especially those containing a large number of pictures and the static page sites) and greatly enhances the stability of the above kinds of sites.

（2）Mirror service. This eliminates the effects caused by the interconnection bottlenecks between different operators, puts into effect the acceleration of the inter-operator network and ensures users of different network be all able to get good access quality.

（3）Remote acceleration. This provides the remote access user with intelligent and automatic selection of Cache server according to DNS load balancing technique. The remote access speed increases by selecting the fastest Cache server.

（4）Bandwidth optimization. This automatically generates the remote Mirror cache server of the server, so the remote access user can read data from the cache server, thus the remote access bandwidth is reduced, network flow is shared and the load of the original station WEB server is lightened.

（5）Cluster anti-attack. The broadly distributed CDN nodes and the intelligent redundancy mechanism among the nodes can effectively prevent hacker attacks and reduce the effects by various DDOS attacking the website, and meanwhile can ensure good service quality.

Sugon has the most complete and longest product line in the industry, and has assisted Blue Telecommunications, the largest company in CDN industry, to build its CDN service network. Sugon has possessed rich solutions and experiences.