What is an example of a CDN?
A large portion of all internet content is delivered through CDNs. Here is a simple example:
If you were in New York and wanted to view the website of your favorite store in London that’s hosted on a server in the UK, you would experience slow content load times if the request had to travel all the way across the Atlantic Ocean. To remedy this, a CDN would store a cached version of the London website content in multiple geographical locations around the world, also called “points of presence” (PoPs). These PoPs contain their own caching servers and are responsible for delivering that content close to where you’re located in New York. Content delivered from a server closest to your physical location gives you a faster, high-performance web experience.
How does a CDN work?
The mission of a CDN is to reduce latency. Latency is that annoying delay you experience when trying to access a web page or video stream before it fully loads on your device. Although measured in milliseconds, it can feel like forever, and may even result in a load error or time-out. Some content delivery networks alleviate latency by reducing the physical distance that the content needs to travel to reach you. Therefore, larger, more widely distributed CDNs are able to deliver web content more quickly and reliably by putting the content as close to the end-user as possible.
Let’s say it’s the weekend and you want to kick back and stream the latest Hollywood movie release — the CDN finds an optimal server on its network to serve up that video. Usually, that will be the server closest to your physical location. The media files will be cached and remain on that content delivery network server for other user requests in the same geographic area. If the content you requested is unavailable or outdated, the CDN service will store the newly fetched content to serve any future requests.
While the delivery of website content is a common use for CDNs, it’s not their only function. In fact, CDNs deliver a wide variety of content that includes: 4K and HD-quality video, audio streams, software downloads such as apps, games, and OS updates, and much more. Potentially any data that can be digitised can be delivered through a content delivery network.