We calculate CDN for your services

CDN services in comparison

A horror scenario for web service providers: the digital product is requested but cannot reach the customer. Site users complain that the website loads slowly, videos freeze, and downloads don't work. The reason for this is often an overload of IT capacities. Because data-intensive content such as videos and streams sometimes push existing capacities to their limits. One answer to the increased data volume is: Content Delivery Network (CDN). Without these server systems, many things in the network would not work or would work only slowly today. Internet giants like Apple and Google rely on the server infrastructure to operate their services. But CDN is also relevant for small and medium-sized companies and eCommerce operators.

  1. A content delivery network is a network of spatially distributed servers. Such an IT infrastructure is used by media service providers, for example, to deliver content to their customers smoothly and with short loading times.
  2. Content delivery networks make data-rich content such as video streams available almost instantly. Even for end users who are far away from the actual web server, there are no serious delays. The decentralized server architecture can significantly relieve your own hosting capacities.
  3. The usefulness of a CDN depends heavily on the website. In the case of an internationally accessed page with data-intensive content, you shorten the loading time for your customers enormously.

What is a CDN?

A content delivery network (CDN) consists of a large number of spatially distributed servers. Its main purpose is to ensure the shortest possible loading times, even for data-intensive services and requests from geographically widely separated areas. How many and which servers in the network are actually accessed depends, among other things, on the number of users, their location and the type of content. CDNs have this dynamic alignment ahead of conventional server-client networks.

Sometimes there is talk of a content distribution network rather than a content delivery network. Both terms are usually used synonymously.

How does a content delivery network work?

The core function of a CDN is the fast delivery of web content. The respective website or web server of the customer is integrated into the network via an API. Once this has happened and the most important settings have been made, delivery runs automatically in the background. This is a crucial difference to other cloud services such as cloud backups, which primarily provide storage space.

Akamai, one of the largest CDN providers, states that up to 30 percent of daily traffic worldwide is delivered through its servers.

A content delivery network consists of a main server and regionally distributed cache servers (also known as replica servers). Upon request, first the cache server that is closest to the user. The system determines whether the requested content is stored in the cache. If this is not the case, it forwards the request to the main or web server. It also saves the requested content for the next page view.

The cache servers cannot automatically deliver all web content. Originally they were only for static content intended. This includes image and video files as well as JavaScript and CSS files. Over time, the range of functions has expanded. Depending on the offer, you as a customer can now also provide dynamic content and streams via cache servers.

The term "cache" describes the intermediate storage, which is intended to shorten loading times for applications. Instead of reloading data each time it is accessed, the fast cache keeps it ready for access.

Two content delivery methods: pull and push

With CDN, two different methods are used to load data onto cache servers. At a Push CDN (German: schieben) a copy of the data from the web server is automatically loaded onto the cache server at specified times. At a Pull CDN (German: pull) the data transfer takes place in the opposite direction. The cache server pulls the data from the web server after a page visitor has made a request via the server for the first time.

Load distribution in the CDN

A CDN handles peak loads better than a single web server. If servers fail, they are also flexibly replaced. Ideally, the site visitor will not notice the failure. The service offered remains accessible online. This increases sales security for online service providers. In the case of a conventional server, on the other hand, a server failure would mean a complete page failure.

International provision of web services

The spatial distribution of the servers reduces the waiting time for end users. This is especially true if the site visitor (client) is physically far away from the actual web server. In the case of a conventional web server located in Frankfurt, the server response time increases if the page is accessed, for example, from the United States. The geographical distribution of the cache servers of a CDN prevents this delay.

The selection and implementation of a CDN requires knowledge of programming languages ​​as well as API and protocol knowledge. You should therefore have a system administrator or developer do both.

The advantages of a content delivery network

  • User experience: The integration into a CDN shortens the Server response time a website and thus the waiting time for users. In e-commerce in particular, this is often a basic requirement for users to perceive an offer as successful.
  • Traffic increase: Pages that load faster have a positive effect on search engine optimization (SEO). The short loading times increase traffic and ultimately increase sales of the website.
  • Security: A CDN reduces the risk of website failure. In addition, many CDNs improve protection against DDoS attacks from the network.
  • Internationalization: The dynamic server networks enable a consistently high level of user-friendliness even with internationally oriented websites.
  • Possible cost savings: An intelligently used CDN will help you to reduce IT costs. Because when capacities are overloaded, it is sometimes cheaper to connect the core server to a network than to buy additional capacities from the hosting provider.

The disadvantages of a content delivery network

  • Benefits depending on the individual case: How great the benefit of a CDN is and whether traffic increases are achieved depends on the individual case. For example, if you run a site that is primarily visited by users from Germany, the CDN is likely to have little effect.
  • Not a panacea: A CDN can take the strain off the trunk server enormously, but it cannot compensate for a fundamental overload and careless maintenance. Before deciding for or against a content delivery network, the website should therefore be thoroughly analyzed.

This is how CDN providers calculate the price

The costs depend on the bandwidth, the range of functions and the locations of the cache servers. Many CDN providers set different prices depending on the region of the world and the volume of data. Basically, the higher the traffic, the higher the costs. Additional functions such as custom SSL certificates and cache server configurations also often mean additional costs. Medium-sized companies and operators of smaller e-commerce sites, on the other hand, usually pay a three-digit monthly fee for access to a CDN. For large companies and media services, the costs can be several thousand euros. Private customers and blog operators provide certain CDN providers free access available, although the range of functions remains limited.

CDN only for big players on the net?

Large, internationally operating companies can hardly do without CDN today. Data-intensive content and competitive online markets mean that there is almost no alternative to increasing performance. But also for medium-sized companies and E-commerce provider such an international server network is becoming more and more important. It relieves the existing hosting resources, shortens loading times and increases the security of your site.

Whether the connection to a CDN is actually worthwhile depends largely on these questions:

  • How international is your site?
  • Would you like to provide videos and images on your site?
  • Are there lost sales due to page failures?
  • Are your existing hosting resources often overloaded?

Important functions of the CDN

CDN offers are basically always based on the same principle. The main differences between the providers and tariff options are with regard to the range of functions and the configurability of the cache server.

Configuration of the cache server

As a customer of a CDN, you can, for example, set how long the content is on the server and how it is updated (push configuration). There is also a function for cleaning up the cache server when data is no longer required.

The type of data available

Which files you can store on the cache server depends on the offer. Static elements are the standard. The browser relies on this data to load the website. In addition to static and dynamic data, so-called Data streams (Audio and video) more and more important on the Internet. These place special demands on the server because the streaming file is played back while the data is being transmitted. Meanwhile I have to a constant transmission speed to be guaranteed. Otherwise the stream will stall. Different protocols are used for the transmission. Examples of services provided through CDN are software downloads, HD video streams, podcasts, and system updates.

SSL certificates

As a rule, the service providers offer SSL certificates for their server network. They are used to encrypt transmitted data and are used, for example, to transfer data in payment transactions. Make sure that the CDN provider also allows you to upload custom SSL certificates. For e-commerce operators it is important that the CDN complies with the requirements of the Payment Card Industry Data Security Standard (PCI). This regulates the provisions of credit card payments.

Analysis functions

Different analysis tools are available depending on the provider. This makes it possible to track the bandwidth used and the number of connections with cache servers.


The connection of the web server to a content delivery network can enormously shorten the server response time and thus the loading time for the user. This has a number of positive effects: The user experience improves, search engines record the reduced latency, and the site's traffic increases. In addition, the distribution of the requests on a server network contributes to the increased security of the site. The network compensates for server failures and is better able to counter any threatening DDoS attacks.

If the site visitors come primarily from German-speaking countries, the positive effect may not be very high. The same applies to pages that do not provide data-intensive content. So you should weigh up whether the purchase of a CDN is worthwhile for you. The trusted.de overview will help you.