What is a CDN and why is internet content copied worldwide

When you open a webpage, you usually care about one thing. That it loads quickly and without issues. However, between clicking on a link and seeing the page, several operations occur that we usually don't see. Images, videos, styles, and other files have to be created somewhere, stored, and then reach you. Where they are loaded from and the path they travel affects not only the speed of the website but also its stability.

One of the technologies that take care of this is CDN.

What is a CDN and why was it created

CDN stands for Content Delivery Network, a network of servers located in different parts of the world.

As the internet grew, delivering content quickly and reliably became increasingly challenging. Websites began to contain more photos, videos, and other data that needed to be transmitted to an ever-growing number of users.

CDN offers a different approach. Instead of one central point, it uses a larger number of servers that collectively help deliver content to users. Today, streaming services, social networks, news websites, e-shops, and many other online services use this technology.

Why data doesn't have to travel across the world

The internet is often described as a virtual environment. In reality, it relies on physical infrastructure made up of cables, servers, and data centers. Every file you view has to travel a certain path.

If a website were only available from one location, all visitors would have to turn to it regardless of where they are coming from. This can be a problem, especially for services with a global audience.

Therefore, CDN stores copies of selected content in multiple locations. A visitor from Europe can get data from a European server, while a user in Asia can get it from a server closer to their location.

The original website remains the same. Only the place from which part of its content is delivered changes.

What does CDN cache

Even though CDN is often talked about as a network of copies, it doesn't mean it automatically stores everything. It uses cache memory. It primarily stores content that doesn't change between different visitors.

Typically this includes:

• images,
• videos,
• logos,
• fonts,
• JavaScript files,
• Cascading Style Sheets CSS.

A different situation occurs with content that is unique to each user. For example, if you view your shopping cart or log into online banking, the system has to work with your specific data. Such content is usually not created in the CDN but directly in the original system.

This is where the distinction between static and dynamic content comes in. Static content can be easily stored on multiple servers simultaneously. Dynamic content, on the other hand, is created as needed.

Why some websites load almost instantly

The speed of loading web pages is not only affected by the quality of the internet connection. It's also important how efficiently a website can work with content that visitors repeatedly load.

If frequently used files are stored in the CDN network, the website does not need to provide it from the original source for each request again. This way, part of the traffic can be handled directly from copies stored in the CDN network. The result is usually faster response times.

CDN can do more than just speed up the web

The benefits of CDN don’t end with faster page loading. The technology also brings several other important advantages:

• Higher service availability. If a problem occurs on one server or one data center, another part of the network can take over the traffic. The risk of total website unavailability is thus lower.
• Better handling of peak traffic. When a large number of people visit a website in a short time, not all requests have to go to one place. Traffic is distributed among multiple servers.
• Assistance during infrastructure outages. A distributed network is generally more resilient to technical problems than a solution based on a single server.
• Protection against certain cyber-attacks. CDN can help mitigate the impacts of DDoS attacks, where attackers overwhelm the website with huge numbers of requests.
• Lower load on the original server. Part of the content is delivered to visitors from copies stored in the CDN network so the original server does not have to process every request by itself.
• More efficient use of bandwidth. Repeatedly used files do not need to be constantly transmitted from one location, which can reduce infrastructure demands.

While visitors usually appreciate faster loading the most, website operators often focus on something else. The ability to keep services available even when traffic surges or part of the infrastructure fails.

Why today's internet can't do without CDN

CDN is one of the technologies that most users don't even think about. Yet they help ensure that photos, videos, or websites reach millions of people quickly and reliably.

Without a similar principle, many websites, streaming services, or social networks would function much less efficiently today.

Frequently Asked Questions

What does the abbreviation CDN stand for?

CDN stands for Content Delivery Network, a network of servers located in various places worldwide, which helps deliver internet content faster and more efficiently.

Does CDN store entire websites?

In most cases, no. CDN typically stores only selected content, such as images, videos, fonts, or other files that don't change between visitors.

What is the difference between CDN and web hosting?

Web hosting keeps the original content of a website. CDN creates its copies and helps distribute them to users from various locations worldwide.

Does CDN help protect a website from attacks?

Yes. Some CDNs offer protection against DDoS attacks and other security features that help protect web infrastructure.

Do only large websites use CDN?

No. Although used by the world's largest internet services, smaller websites, e-shops, or online magazines can also benefit from their advantages.