What is CDN?

Submitted by ruo on Wed, 06/07/2017 - 13:16

CDN stands for content delivery network or content distribution network.The main function is cache content in different location and use load balance technology to let user to get the content from the most suitable cache server. For example, for users in China, we let them visit nodes in China and users in Europe, visit nodes in Europe.Through close-by visit to faster website loading time.

Differences between CDN and traditional website visiting

Traditional website visiting path:


  1. Input domain name-resolution server to get IP address accordingly
  2. send request to the server
  3. returning data

With CDN


  1. Input domain name-resolution server to get CNAME accordingly
  2. Resolution the CNAME and get IP address of cache server.
  3. send request to the IP address of cache server
  4. returning data

Unlike traditional network access, CDN network has a Cache layer between users and server, which guide user’s request to the most suitable cache server nodes instead of source serve to faster access.

CDN's work flow

  1. User send request
  2. Resolution via intelligent DNS(according to user’s geographic location,Access network type find the cache server which has shortest route to user and lightest load)
  3. get cache server’s IP
  4. check if the cache server has target data
  • If Yes :returning data to user
  • If No: send request to source server, then save data in cache server and finally returning data to user

In a word, the working principle is realize the choosing of most suitable node through authoritative DNS and reduce resource server’s stress through cache.

Application of CDN


  1. Static page:Pictures, small file, blogs 
  2. Downloading large files: download software, watch videos or hosting images website.
  3. Speed up Dynamic website: living website
  4. Speed up application: app 

If you have any question please feel free to contact us. We're glad to help you. Especially for people who have overseas website and want to improve user experiences in China. We can provide CDN avoid the ICP license problem.

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