What is CDN, and how does it work?

Do you use Netflix or Disney+? Can you imagine distributing video content to every point in the world instantly? To be able to stream video to millions of users at the same time? It is a huge effort! You can’t do it with a single mega server. You will need a network of many, and those servers can’t be just connected in a single location. They need to be strategically distributed to different spots where the consumers are. Here comes the CDN and all its glory. It is the enabling technology that is currently killing the standard television. 

History of CDN

What is CDN?

CDN means content delivery network. It is a network of servers that cover a great geographical area, and the servers have very specific locations. The goal is to cover well the territory where the potential visitors come from. To have servers that cache data (code, images, videos, etc.) as close as possible to the visitors. That way the visitors will get better and faster service. The other good result of the CDN is load balancing that will reduce the stress on the primary server. 

Benefits of the CDN

  • Boost the speed. All queries that a visitor makes will travel a lot less. From the users’ computers, they must reach the first secondary server that has the data in its cache. Shorter distance means a faster result. 
  • Less bandwidth. Most of the queries of the visitors will be answered by the secondary servers. That means less traffic for the primary one. The primary still needs to communicate the information to the secondary servers, but it is still less bandwidth. Especially if we are talking about videos.  
  • Better uptime. Even if one of those cache servers is down, the answer could come from the next one. The worst case that the primary is down, the cache in the rest of the servers will still be available, and downtime might not be felt. 

How does CDN works? 

CDN works by using a vast network of servers with cache data to distribute content to the visitors. The CDN provider needs to choose wisely where they want to have their points of presence (PoP). They choose between the Internet exchange points (IXPs). Those are very important infrastructure points, where the internet speed is massive. The CDN benefit from the speed and the strategic location. The cost is high, and this is why the CDN providers can’t have PoP in all of the available IXPs. It could have been wonderful if every CDN could have countless PoP, but the number is usually in the lower 20s and in very rear cases goes beyond 40. 

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Who can use CDN? 

Everybody! Yes, really everybody could use CDN. If you have a media company, it could be your only hope to distribute content to further locations. The CDN can make miracles for e-commerce sites too. Especially if they work on different markets like multiple states (The US) or multiple countries (European Union). 

News sites, bloggers, online services, and many more could benefit from it.

Honestly, some of the CDN prices are very affordable and won’t be a problem, even for a small company, to pay a monthly subscription. 


The CDN is a marvelous technology that catches the eyes of more and more people every day. Google is pushing us for faster loading sites for a long time already, and a content delivery network could help. You could be able to keep the heavy and well-decorated design of your web site and still load fast. Sounds great, right?  

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