CDN is the full name of the Content Delivery Network, that is, Content distribution Network, the CDN is to build on the existing Network based on intelligent virtual Network, relying on the edge server deployed in all over the world, and through the load balance center platform, Content distribution, dispatching function modules, such as required for the user to get to the nearest Content, reduce the Network congestion, improve user access the response speed and shooting, the key technology of CDN main Content storage and distribution of technology,