High Concurrency and Large Traffic Topics---5. CDN Acceleration

High Concurrency and Large Traffic Topics---5. CDN Acceleration

1. Summary

One sentence summary:

CDN is to add several more node servers, and choose the server closest to the user to serve the user. If it is implemented, you can use the functions provided by Alibaba Cloud and Tencent Cloud. It is simple and convenient, and my mother no longer has to worry about me.

 

1. What is CDN?

Content Delivery Network: The full name of CDN is Content Delivery Network, that is, Content Delivery Network

Principle: Find nearby nodes to provide services to users

 

Avoid bottlenecks and links on the Internet that may affect the speed and stability of data transmission as much as possible, so that content transmission is faster and more stable
. A layer on the basis of the existing Internet formed by placing node servers everywhere in the network The intelligent virtual network
CDN system can redirect the user's request to the service node closest to the user in real time according to the network traffic and the connection of each node, the load status, the distance to the user and the response time and other comprehensive information.

 

2. What are the advantages of using CDN?

Access speed: Local Cache acceleration improves the access speed of enterprise sites (especially sites with a large number of pictures and static pages).

Cross-operator network acceleration: ensure that users of different networks have good access quality: such as North China Unicom, South Telecom

Intelligent and automatic Cache server selection: Remote access users intelligently and automatically select Cache servers according to DNS load balancing technology

Reduce remote access pressure: automatically generate a remote mirror (mirror) cache server of the server, read data from the cache server when remote users access, reduce the bandwidth of remote access, share network traffic, and reduce the load of the original site WEB server, etc.

 

3. What kind of CDN can effectively prevent hacker intrusion?

Widely distributed CDN nodes plus intelligent redundancy mechanism between nodes

 

4. What is the relationship between the CDN node server and the original server?

Mirror: The CDN node server is equivalent to the mirror of the original server, which caches the data of the original server

 

5. How does the CDN node server work?

If the node server has it, return it directly to the user, if not, pull a data image from the original server, cache it and return it to the user

 

6. How does CDN work (the difference from traditional access)?

Traditional access: the user enters the domain name in the browser to initiate a request --> resolve the domain name to obtain the server IP address --> find the corresponding server according to the IP address --> the server responds and returns data

Access using CDN: User initiates a request --> Smart DNS resolution (judging geographic location, access network type, and selecting the server with the shortest route and the lightest load based on IP) --> Get the cache server IP --> Return the content to User (if there is one in the cache) --> initiate a request to the origin site --> return the result to the user --> store the result in the cache server

 

7. What are the applicable scenarios of CDN?

Massive Static Assets: Accelerated distribution of a large number of static assets in a site or application, such as CSS, JS, images and HTML

large file download

Live streaming sites, etc.: Compare bandwidth consumption

 

8. Implementation of CDN?

BAT, etc. all provide CDN services

LVS can be used for Layer 4 load balancing

Available Nginx, Varnish, Squid, Apache TrafficServer for Layer 7 load balancing and caching

 

9. How to do reverse proxy?

Use squid reverse proxy, or reverse proxy such as Nginx

 

 

 

 

2. The content is in the summary

 

 

 

 

Reprinted in: https://www.cnblogs.com/Renyi-Fan/p/11047890.html