Explanation of CDN Working Principle

When a user visits a content URL, the local DNS system will resolve it, and finally hand over the domain name resolution to the CDN dedicated DNS server pointed to by CNAME.

The DNS server of the CDN returns the IP address of the CDN's global load balancing device to the user.

The user initiates a content URL access request to the CDN's global load balancing device.

The regional load balancing device will select a suitable cache server for the user to provide services. The selection basis includes: judging which server is the closest to the user according to the user's IP address; judging according to the content name carried in the URL requested by the user Which server has the content required by the user; query the current load situation of each server to determine which server still has the service capacity. Based on the comprehensive analysis of the above conditions, the regional load balancing device will return the IP address of a cache server to the global load balancing device.

The global load balancing device returns the IP address of the cache server to the user.

The user initiates a request to the cache server, and the cache server responds to the user request and transmits the content required by the user to the user terminal. If there is no content that the user wants on this cache server, and the regional balance device still assigns it to the user, then this 

server will request the content from its upper level cache server until it is traced back to the origin server of the website To pull the content locally.

CDN is a strategically deployed overall system, including distributed storage, load balancing, network request redirection, and content management. Content management and global network traffic management are the core of CDN. By judging the user's proximity and server load, CDN ensures that the content serves the user's request in an extremely efficient manner.

Local Cache acceleration improves the access speed of corporate sites (especially sites containing a large number of pictures and static pages), and greatly improves the stability of the above-mentioned sites.

The mirroring service eliminates the impact of interconnection bottlenecks between different operators, realizes network acceleration across operators, and ensures that users in different networks can get good access quality.

Remote access users based on DNS load balancing technology, intelligently automatically select Cache server, choose the fastest Cache server, and speed up remote access

The remote mirror cache server of the server is automatically generated, and the data is read from the cache server when remote users access, reducing the bandwidth of remote access, sharing network traffic, and reducing the load of the original site WEB server.

The widely distributed CDN nodes and the intelligent redundancy mechanism between nodes can effectively prevent hacker intrusion and reduce the impact of various DDOS attacks on the website, while ensuring better service quality.