What is a CDN

What is a CDN(Content Delivery Network) – Find out!

Today we are going to find out what is a CDN, also knows as Content Delivery Network, and make some comparations.

Even if broadband expansion in Germany has not yet progressed at the same pace everywhere, it can already be said that the Internet and data transmission have made proverbial rapid progress.

Who doesn’t (reluctantly) remember the old 33.6 modems with which one dialed into the Internet and then could go for a coffee until a website was set up.

Fortunately, these times belong to the past. In the meantime, well-optimized websites are called up in milliseconds and displayed in the browser. Even on mobile devices, the transmission has become much faster, thanks to LTE. Today’s users expect content to be delivered quickly. Analytics tools can be used to measure how the bounce rate increases if the website loads too slowly.

One should also not forget the fact that Google has made website speed one of its ranking factors. This is only logical because Google has set itself the goal of presenting the user with the best quality website for his search query. This also includes the user experience, and a slow loading website does not give the user a positive experience.

In the context of a blog article, we have already presented a few possibilities of PageSpeed optimization. The use of a CDN is also one of them. We offer this here today.

What is a cdn

So what is a cDN really?

The abbreviation CDN stands for Content Delivery Network – it is a network which provides content. So far, so good. Why can this be useful for your website?

A typical use of a CDN is in the image area. The principle is that images are not stored on your server and accessed by users there, but are distributed in a network of servers all over the world. The photos are then just “embedded” like an external source on your website. This saves its own resources.

Here are just a few examples of data that can be hosted on a CDN and what is a CDN:

  • Images: PNG, JPG, SVG, GIF, TIF
  • Style sheets: CSS
  • JavaScript: JS
  • Video and audio: FLV (Flash), HLS, MP4 (HTML5 videos), MOV (QuickTime), WMV (Windows Media), MP3 and WAV
  • Web Fonts: EOT, TTF, OTF, CFF, AFM, LWFN, FFIL, FON, PFM, PFB, WOFF, SVG, STD, PRO, XSF, and many more
  • Other file formats: HTML, JSON, PDF, DOC, PPT, XLS, EPUB, ODT, ODP, ODS, TXT, RTF, ZIP

On the Internet, data is not sent, as is the case with television or radio but is retrieved by a browser on servers. If no CDN is in use, requests from all over the world always come to the one server where the data is hosted. Due to the architecture of the Internet, however, the requests do not come directly, but via different nodes. These requests can, of course, take some time until the data is evident to the user in the browser.

The CDN then delivers the files from the server that can provide them with the fastest. This avoids long loading times and distributes high access rates. Usually, this has a positive effect on the loading times.

As a webmaster, you first store all your images on a source server. Copies of the data are then stored on the servers connected to the network and delivered to the user.

CDN Example

Another advantage of a CDN is that the server that is closest to the user usually plays the files. This might not be so interesting for a German blog or a German niche site.

Still, for e-commerce sites with multiple languages or country versions as an example, this can be very interesting.
Pictures are delivered to a visitor from North America by a server from North America, a user from Europe by a European user and an Australian user from Australia.

Of course, this depends very much on the size of the network. So the ways to the visitor and the loading time for the visitor should be kept as short as possible.

Advantages of a CDN

  • Better loading times
  • Increased stability
  • Lower costs for own hosting
  • Further analysis options through statistics from the CDN provider

Example of CDN Provider:

  1. StackPath – Number 1 in terms of quality
  2. Cloudflare – Pretty good but not in terms lately.
  3. BunnyCDN – Pretty Decent with a good list of features.

Of course, there is more than that – You should pick your provider with care.

Disadvantages of a CDN:

  • Higher effort: Both the setup and the operation of a CDN naturally involves higher efforts compared to a single server where all files are stored.
  • Security concerns: More servers also mean more points of entry for hackers into the system. Especially JavaScript files are targets for hackers.
  • Loss of control: Since you don’t have the data on your server, but distribute it worldwide, you naturally give up a bit of control over the data. For example, you do not want files to be hosted in the USA. This is usually unavoidable with a CDN.

What does a CDN cost?

Here there is a broader range of costs. There are even free solutions. Cloudflare and the Google App Engine would be such solutions for free. However, the offers are designed for entire web applications. The storage of static content is also possible there.

The service KeyCDN.com is also top-rated. However, the service there is not free of charge. As a rule, the first ten terabytes of KeyCDN cost 0.04 US dollars per gigabyte.

For large websites, first, large solutions are appropriate. The largest German provider is PlusServer. Here, for example, data from large car manufacturers, insurance companies, travel portals, and many others are hosted.

Who should think about a CDN?

Especially high traffic sites should use a CDN because the load of the traffic is distributed optimally. Even areas that transfer many files can benefit from a CDN – e.g. if many pictures or many videos are played. As already explained, a CDN makes sense if visitors from many countries of the world access the website, because the nearest server then provides the data.


Today we have learned what is a CDN and how helpful that could be to our sites – We hope you enjoyed reading about it!

Useful Links For you:

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top