What is a Content Delivery Network (CDN)?

StriveCast Blog

CDN: real-time internet video delivery on a global scale

The internet is growing rapidly and still even increases its growth rate. While back in 2005 about 1 billion people used the internet on a daily basis, today there are 3.5 billion internet users that share 4 Exabytes (4,000,000,000 Gigabytes) of data every single day. To deliver such an amount of data to users around the world, a strong infrastructure is needed. This global infrastructure (also called backbone) consists of giant data centers and huge cables that connect all parts of the world into one great network. Some of the data centers form the so-called “subnetworks”.

This happens if, for example, a company starts to build new data centers to provide delivery services for other big companies that generate high data traffic. We call these sub-networks content delivery networks (or CDNs). Basically a CDN is nothing more than a bunch of globally distributed computers that are directly connected and move data from one end to another.

A good example of this is YouTube. There are more than 6 billion hours of video each month watched by YouTube users. As you can imagine (or… maybe you literally can’t do this) this causes a very high amount of traffic. If just one simple machine within the internet would host Youtube, it had to deliver every single video, also. This single instance would have to handle every data request on the platform.

CDN, What is a Content Delivery Network (CDN)?

Why should we think about these CDNs?

Apart from the fact that this would be highly inefficient, think about latency

What happens if a user requests data while being thousands of miles away from the server? Well, since a video will never change again after it is uploaded to YouTube, one could set up a second YouTube server and copy all the videos on this second machine. By doing so, both servers share information with a number of requests and offload each other. At the same time, latency could be decreased for many people. And if this is possible, why not set up servers all around the globe?

For YouTube, this would mean a pile of extra work. Setting up, maintaining and managing all these servers would consume time, knowledge and, of course, money. So instead of building such a big delivery infrastructure itself, YouTube could just use an existing CDN because this is exactly what CDNs are made for.

CDN, What is a Content Delivery Network (CDN)?

Now viewers from all countries view all the videos hundreds of thousands of times already available right in front of them. Since the videos won’t change again, we can just store them into the CDN keeping them ready to go out whenever a viewer sends a request. We call this technology caching. It is one of the most efficient ways to reduce internet traffic because it minimizes problems at a fraction when streaming Video-On-Demand (VOD).

CDN for live video?

About 2 years ago a new streaming trend started growing and still grows rapidly. This new trend is a big threat to CDNs since it also causes high traffic but is almost completely resistant to caching: Live Video Streaming. Live video data is uncachable because of two reasons: 

  • It changes every single second so there is no time to cache it

  • As soon as data is available it is almost irrelevant because it is real time and in the next second – gone

To make caching work for live OTT at any chance you require very special server configurations. In fact, these configurations are even harming a statically determined caching system. In order to make a CDN available for live streaming at all, you require a dedicated CDN with its main focus on live data. But there is more! Most CDNs are working on a global scale. This means that a single CDN can consist of several thousands of caches that connect multiple layers among each other. There are a few very strong caches that transfer their data to more, smaller caches. This is a good approach to build a resilient, reliable CDN for static content. However, this multi-layer approach is a deal-breaker for live content. Since the cache-to-cache transmission takes time, latency grows higher and higher.

The factors that are crucial to achieving a reliable video stream​

Summarizing these facts, we now know what is needed for OTT live streaming:

  • A CDN that only focuses on live content

  • Few but very strong caches to reduce latency

  • A flat CDN structure without multiple caching layers

StriveCast OTT is the world’s first live-only content delivery network that exactly fits the needs to globally scale OTT live streaming. With our CDN solution, we make live OTT affordable, feasible and scalable. Download our StriveCast OTT Datasheet below and get all the tech-specs on OTT video Delivery.

After all, the world of live streaming has changed the world of CDNs. And the future is built upon the contribution of all of us. With peer-to-peer delivery, literally, all of us contribute to a more reliable stream and a lower latency. The future of content delivery is live. 

Are you interested to know why P2P will boom this year? Then you should not miss our blog post about the four reasons that make P2P CDN so relevant nowadays. Click here to learn more.

About StriveCast

StriveCast is a leading technology provider for eCDN solutions. Our WebRTC-based P2P mesh network is used by large companies like Swisscom, Siemens, Gazprom, and NEP group to solve the problem of network congestion during live events. Based in Germany, we are constantly improving and adapting our cutting-edge P2P technology in order to provide the next generation of enterprise video delivery. Today, StriveCast connects over 150,000 users worldwide on a daily basis, saving customers up to 95% of CDN traffic with a unique server-side-managed Peer-To-Peer network.

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