Application of CDN in game field

One 、 What is? CDN ？

CDN（Content Delivery Network）, namely Content distribution network , It is a distributed network group composed of multiple edge server nodes . The use of Global load balancing Technology points users' access away from users lately It works normally Streaming media server On , The streaming media server directly responds to the user's request .

Two 、 Why use CDN ？

Actually use CDN Technology can bring our game customers better Gaming experience , Because we all know , Before use CDN When it comes to technology , Every resource request will request the source Host The server , If in High concurrency scenario Next , Source Host The server will bear more pressure , There is even the possibility of downtime .

So use CDN Technology mainly has the following functions ：

• Share the source station pressure ;
• Avoid network congestion ;
• Accelerate website content distribution , Speed up resource access .

3、 ... and 、CDN Application scenarios

1、 Static file distribution

• Picture file ;
• CSS file ;
• JS file ;
• …

2、 Big file download

• Game packages ;
• Upgrade package ;
• Application updates ;
• …

3、 Audio and video on demand

• transcoding ;
• decode ;
• Storage ;
• …

The above scenarios are applicable to the game （ Of course, it's not limited to games ）、 Movies 、 News media and other fields .

Four 、CDN Accelerate the principle

Suppose the accelerated domain name is www.zhurse.com

1、 Customer access www.zhurse.com

• Local DNS analysis ;
• Returns the name of the domain name CNAME Domain （www.cdcd.example）;

2、 Local DNS towards CDN Of DNS Scheduling system requests www.cdcd.example The parsing record of , And assign the best CDN Node IP Address , And then back to the local DNS.

3、 Local DNS obtain CDN Of DNS The scheduling system returns the best CDN node IP After the address , And put the best node IP Address returned to user , Users get the best CDN Node IP Address .

4、 Users to the best CDN node IP Address initiates an access request to the resource .

• If the best CDN The node has cached the resource , The requested resource will be returned directly to the user , The request ends .
• If the best node does not cache the resource or the cached resource has expired , Then the node will initiate a request for the resource to the source station . After obtaining the resources of the origin station, combined with the user-defined cache policy , And cache resources to CDN The node then returns to the user .

Summary

For static resources , Such as images 、 video 、 Files in the website （html、css、js）、 Software installation package and other files , Use CDN Technology can see obvious effects .

For dynamic resources , Such as asp、jsp、php、perl Wait for the documents , Use CDN It doesn't work , in other words CDN Cache acceleration of is not suitable for accelerating dynamic content （ That is, dynamic content that changes in real time cannot be cached ）

therefore , For dynamic resources , We can use Speed up the whole station Technical means to achieve （ Such as route optimization 、 Transmission optimization ）.