How does the famous CDN acceleration service accelerate access and distribute content?

Hello everyone, I am Bernie, an IT pre-sales engineer.

This article briefly discusses the famous CDN content distribution service and how CDN achieves service acceleration. Welcome to read ~

We assume that somewhere on the earth, there is an Internet Content Provider. In another place, tens of thousands of miles away, there is a brother who suddenly wants to visit the website business.

Then, an astonishing scene happened: due to the long communication distance, the web page was stuck and even a picture took 2 or 3 seconds to load, not to mention loading a video.

Let me ask, can such a website still provide business access services to global users?

It is estimated that it can only provide services to users who are relatively close, similar to the operation of local services within a metropolitan area network.

What if the ambitious boss refuses to give up and wants to serve more users and make more money?

Some people may say: "Then build more resource pools, at least one central node and multiple edge nodes under it." Something like the following.

The idea is good, but where is the money?

The cost of building a resource pool is very huge. A single server costs about 100,000 (more than that for a good one), including network cables, switches, routers, IDC computer rooms, racks, electricity, and operation and maintenance manpower....

It will cost a lot of money!

However, the business still needs to be developed. We must move forward even when there are difficulties, and we must move forward even when there are none!

At this time, you need to know a little about CDN.

What is CDN?

There is a group of wealthy sponsors who saw the business opportunity of server leasing. Therefore, they spent a lot of money to build many resource pools in many countries around the world, or in many places in a certain country. Then, they leased some servers in these resource pools to bosses who needed to expand their business but did not have enough funds to build edge nodes.

These wealthy sponsors are CDN service providers.

The full name of CDN is Content Delivery Network. Simply put, it distributes the content of the central node to many edge nodes close to users, allowing users to access certain services nearby, speeding up access and improving the service efficiency of Internet Content Provider.

In CDN services, the central business node often belongs to an Internet company, and many edge nodes belong to the CDN service operator.

What can CDN do?

The core purpose of CDN is to rely on its natural advantage of being close to users. When users need to request a certain service, they will give priority to requesting the nearest edge node.

Usually, Internet service providers deploy dynamic resources on CDN. The so-called dynamic resources are resources that change frequently and are frequently requested, such as server time. In contrast, static resources are those types of resources that remain almost unchanged for thousands of years.

For example, if the central resources of a certain business are deployed in Shanghai, if a user in Lanzhou, Gansu wants to access the network, he will first access the node near Lanzhou. If the Lanzhou node has the resources he wants, it will process and return the result immediately.

If not, it will request data from the central node and return it to the customer. At the same time, the Lanzhou node will store the accessed data locally so that it can be directly read and returned to the user the next time a request is received.

What are the CDN operators?

As mentioned before, CDN operators need to build edge resource pools all over the country or the world, and provide professional operation and maintenance teams. It is a game for rich people, and the threshold is extremely high.

So what are the well-known CDN operators?

In China, the notable ones include Alibaba Cloud, Tencent Cloud, UCloud, Baidu Cloud, ChinaCache, Wangsu, etc., as well as the three major telecommunications operators (China Mobile, China Telecom and China Unicom).

Foreign CDN giants include CloudFlare, StackPath, Akamai, Fastly, CloudFront, Edgecast, CDNetworks, CacheFly, Keycdn and CDN77, etc. You can search Baidu for detailed information.

Summarize

The above is a brief introduction to the CDN network. CDN has a wide range of applications and can be used for large image files, small file downloads, live streaming, video and audio on demand, full-site acceleration, and security acceleration.

In addition, the CDN network also has load balancing and disaster recovery strategies. For example, if an edge node stops running due to an accident, it will automatically switch to another edge node that is relatively close to the user to provide efficient network services.

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