The full name of CDN is Content Delivery Network, that is, content distribution network. Its basic idea is to avoid bottlenecks and links that may affect the speed and stability of data transmission on the Internet as much as possible, so as to make content transmission faster and more stable. The CDN system can redirect the user's request to the nearest service node according to the network traffic, the connection of each node, the load status, the distance to the user, the response time and other comprehensive information of each node in real time by placing node servers on the network to form an intelligent virtual network on the basis of the existing Internet. Its purpose is to enable users to obtain the required content nearby, solve the Internet congestion, and improve the response speed of users when visiting websites.
When you worry about the speed of opening your website, you find that some large websites have access to hundreds of thousands or millions or even hundreds of millions of users every day, and different users are distributed in the networks of various operators across the country. With such a large number of visits and such a wide coverage, they can still maintain a very fast page access speed, The secret is that these websites all have a large, stable, efficient and technologically advanced CDN (content distribution network).
CDN means content distribution network and acceleration, so website CND service is website acceleration service.
CDN acceleration principle
CDN accelerates the caching of website content at the edge of the network (the place closest to the user's access to the network), and then routes or guides the user's request to the cache server nearest to the user's access to the network or the access effect through the scheduling system when the user accesses the website content. The cache server provides content services for the user; Compared with direct access to the origin site, this method shortens the network distance between users and content, thus achieving the effect of acceleration.
Features of CDN
1. Local acceleration improves the access speed of enterprise sites (especially sites with a large number of pictures and static pages), and greatly improves the stability of the above sites
2. The image service eliminates the impact of the bottleneck of interconnection between different operators, realizes network acceleration across operators, and ensures that users in different networks can get good access quality.
3. Remote acceleration Remote access users automatically select cache servers according to DNS load balancing technology, and select cache servers to speed up remote access
4. The bandwidth optimization automatically generates the remote mirror (mirror) cache server of the server. When remote users access, they can read data from the cache server to reduce the bandwidth of remote access, share network traffic, and reduce the load on the original site's WEB server.
5. The widely distributed CDN nodes of the cluster against attacks, together with the intelligent redundancy mechanism between nodes, can effectively prevent hacker intrusion and reduce various D D. The impact of O.S attacks on websites, while ensuring better service quality.
