Synthesize information you need to know about CDN?

1. The mechanism of action of CDN

CDN is a term familiar to people who work with a website. You can understand it as follows:

'Content delivery network (CDN) is a global network of servers that store copies of static content within websites and distribute them to multiple PoP (Point of Presence) servers.'

From PoP, data will continue to be sent to end-users. Through the CDN, the copy of the content on the nearest server will be returned to the user when they use the website.

For websites that do not use CDN, the data will be stored at a central server and distributed from there. Therefore, the response time of the website depends a lot on this server. For websites using CDNs, the data is returned to website visitors from the nearest server location in the network. No traffic congestion will occur.


2. Benefits and drawbacks of using CDNs


  • Improve user experience, facilitate SEO: optimize bandwidth, speed up access and data transmission
  • Reduce the bandwidth and storage capacity for the root server, save money compared to buying more bandwidth at the host. CDN expands its reach globally, making the website more responsive.
  • Increase the security of the website, prevent attacks. Because the CDN core infrastructure is now protected by the Firewall. Most CDNs are built using a distributed architecture, so it is capable of mitigating any DDoS attack. Thanks to the real IP hiding feature, the CDN will contribute to secure your IP address, preventing attackers from finding your IP.


  • If the CDN server is not located near the user's location, the speed of your website at the location of the customer will be slower than normal.
  • Some common forms of CDN
  • Pull HTTP / Static: After declaring the domain name of the website, it is necessary to use the CDN or the IP of the server. The PoP will automatically access the website and save a copy of the static content inside. You can then access the file on the website with the provided CDN path or use your own domain name for the CDN.
  • POST/PUSH/PUT/Storage CDN: directly upload the content to be distributed via CDN to the server via popular protocols such as FTP or HTTP. This method will save you the server's storage space.
  • Streaming CDN: CDN distributes streaming content (live video streaming) from the server to users. This will save the bandwidth for the original streaming server.


3. When to use CDN

  • Website server located away from users
  • Customer visits to a large website, need to use a lot of bandwidth
  • There are many visits from different countries
  • Use Load Balancing FailOver technique.


4. Note when using CDN services

  • PoP system: choose CDN services that support PoP in countries with the most users.
  • Price and payment method: pay as much as you want, pay fixed by month, year, or quarter


5. Other

  • Which website should use CDN: CDN is suitable for all websites, from websites for normal business introduction purposes. Websites with a lot of user traffic are encouraged to use CDNs.
  • CDN helps speed up websites by speeding up displaying CSS, Javascript, images, and videos as quickly as possible.
  • Should choose reputable CDN services to ensure 100% safety.
  • Difference between VPN and CDN: VPN helps to hide the identity of the end-user. The VPN uses another computer as the access point to the website's server. This makes it possible for users to access blocked content in their location. This content will not be blocked at the VPN server.
  • The difference between CDN and hosting: Hosting is considered a warehouse of goods and services serving the needs of customers. CDN is a transit station to deliver goods to customers faster.
  • CDN is compatible with all devices: computers, tablets, mobile phones
  • Depending on the supplier, each CDN will have different formats


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