The Basic Idea
The principle is very simple: Each website call contains an average of 15 or more elements (images, optics, program code, ...), which are retrieved individually from the server. Instead of picking up all of these from the central server, suitable elements are buffered and kept in a decentralized manner – i.e. as close as possible to the user.
What does "suitable" mean? Or, conversely, what would be "unsuitable"? Unsuitable is all personalized or vulnerable content, such as
- My account balance or shopping cart
- Board minutes or individual price lists
Incidentally, public, but frequently changing information is also not very suitable - imagine the time display just to name one. This can be buffered, but only for a limited time. The less frequent the change (for example, only to the minute) and the more calls are expected, the sooner the inclusion in the CDN should be considered. (Conversely, video streams and similar large amounts of data are particularly well suited, but rather to be treated as a special case.)
Integrating a CDN into TYPO3 is quite simple - technically you just have to make sure that the right file types are no longer addressed via your own server, but by the CDN of your choice.
In addition, a typical practice requirement is the control of the data stored in the CDN - in concrete terms, these may need to be updated or deleted immediately (if necessary automatically).
Incidentally, the use of the SSL standard should now be taken for granted.
Oh, and don’t forget: first of all a CDN provider must be selected and set up. The most important ones can be found under https://www.cdnplanet.com/, and an overview of the price level can be found at the “top dog” Amazon under https://aws.amazon.com/de/cloudfront/pricing/.
Bottom line: Although the costs are influenced by many factors, they are very well organized (for example, "on average below € 0.15 / GB").
And the furnishing effort - if there are no special features – will be within the hourly range! https://www.site24x7.com/web-page-analyzer.html
Is the Chinese core country an important market for you? Then you will face a special challenge, because the “big firewall” of this state has a dramatic effect on speed.
A classic CDN is of limited use, as it is not allowed to buffer content “beyond the wall” - at best this may work for Shanghai or Hong Kong. Backgrounds and information on specialized providers can be found here: https://www.cdnplanet.com/geo/china-cdn/.
Although this is a CDN topic in particular, it has to be emphasized that often the local optimization of the actual performance already allows a lot of improvement.
- Here are some examples:
- Technical optimization (intelligent internal caching, “small calculation” of images and other data, intelligent sequences ...)
- Resource-saving optics
- Powerful hardware
- Special optimizations such as “reverse proxy caching”, static provision of dynamically generated content, and more.
- Optimization of the structures for good cacheability (for example by offloading dynamic content via Ajax)
As always, there are "low-hanging fruits", namely getting the maximum out of it can actually be costly. Thanks to the low costs on this scale, the use of a CDN is certainly interesting from an early stage - of course only for suppliers with international (as in non-European) customers.