What Is Content Delivery Network?

CDNs And Their Different Forms

A Content Delivery Network (CDN) is used to quickly and efficiently distribute various forms of content to a vast multitude of different end points such as smartphones, desktop computers and web browsers. Content Delivery Networks exist in all forms, with some of the most popular being music and video streaming services, such as YouTube and Spotify. This article will examine in detail what CDNs are and how you can exploit their place in the current market.

To put it simply, CDNs transport media to many end users at once. CDNs can be broken down into three different types, however they retain many similarities. Typically, CDNs can be for general purpose, – they deliver all types of media but not as efficiently as a specialised CDN – on-demand video, – services such as YouTube and Netflix would use a CDN specialised for video in order to keep bandwidth at a minimum while still maintaining high video quality – or finally live video. As you may have noticed, CDNs can be a dime a dozen nowadays with various different streaming and general content delivery services popping up and getting their time in the limelight. As it is such a competitive market, it will be important to examine the different types of CDNs and determine which will be the most effective for you.

General Purpose CDNs

General Purpose CDNs are without a doubt the most flexible option that you will have. As aforementioned, they are not strictly limited to any one form of content and can be used for things that you may not expect, such as software distribution not unlike what you would find underneath the hood of your smartphone’s app store. As they can be used for different forms of media, general purpose CDNs rely on a technique known as web acceleration to maintain a decent level of speed and efficiency no matter what content they will be delivering, as they can’t specialise in any one type. Usually, web acceleration is done by having a number of servers in lots of different locations, often near internet service providers’ connection points or even on the same server unit as a popular website. Web acceleration works by the CDN caching content that is frequently requested by the end users, so that it can be delivered more quickly.

This would have been a more viable option in the past, when ISPs were more monopolised, whereas nowadays there is no one major ISP throughout the United States or different countries across the world. Oftentimes you will need to buy into many different servers across the US or, in a global sense, often across different. This can be extremely expensive, as well as raising a problem in regards to language barriers. However, the need to have servers in different countries could potentially allow you to expand into the markets of many countries at once. In a sense, what could be a large initial investment could pay off.

On-Demand Video CDNs

In days gone bye, the standard method of video delivery was to simply send the entire video to the end user before they could view it. This proved to be disliked by both CDN services who were paying for the data to be transmitted as well as end users, who often had to wait for an entire large file to download before viewing their selected content. Eventually that system evolved into one of a progressive download, so to speak, one utilised by many of popular streaming sites active currently such as YouTube. That system has now become something known as HTTP streaming, often used in tandem with adaptive bitrate (ABR) encoding. What HTTP streaming does is to deliver video in the same way as websites load – through using standard HTTP servers it is able to throttle on-demand video delivery, which ultimately saves the CDN in distribution costs. Even with the progressive download system that came before it, if a user’s internet was fast enough they could potentially have the entire video buffered only to close out of it halfway through, meaning half of the video had been downloaded – at a cost to the CDN – for nothing. This is by far the best option for distributing on-demand video, and the most cost effective for the CDN.

On top of that, the adaptive bitrate has become standardised throughout many modern video streaming services, even the live video CDNs utilise similar systems. ABR will check the end user’s network conditions at regular intervals, ensuring their video will stream without buffering at the maximum bitrate their network can currently handle, auto-adjusting as the network improves or worsens. Due to its popularity and effectiveness, there are many different forms of ABRs currently on the marketplace, and essentially every major content distribution company has their own variety.

Live Video CDNs

Live Video CDNs are the youngest of CDN formats, as well as perhaps being the most difficult to create. Unlike its counterparts, live video cannot be cached which means that encoding for these live players has to be very well made and efficient. There are essentially two options when it comes to creating a live video CDN – high-bandwidth between the servers and the end users that can be extremely expensive, or lower bandwidth that repeat the livestream through a repeater closest to the end user. Either way, it guarantees that creating and maintaining your own live video CDN will be difficult and expensive. Delivery costs for the transmitted data also rise sharply with each simultaneous viewer and ultimately would require a massive, constant audience to be truly profitable.

Creating a CDN that can hold under the pressure of many simultaneous viewers is extremely difficult, as you could always have more viewers than expected – causing technical issues – or less – causing money to be wasted on infrastructure that is unnecessary. The immediate challenge in creating a live video CDN is daunting, however it is the youngest market of the three examined in this article and has a massive amount of room for growth.

Why CDNs Are Important To You

If you are a service provider CDNs should be extremely important to you, as staying up-to-date with trends in the digital media delivery can enable you to offer better, more informed options to content distributors and owners. The HTTP delivery system should be at the forefront of your mind as it is beneficial to all parties involved; cheaper costs for the CDN, better viewing experience for the end user.

Content owners should also have an understanding of the different methods of media distribution as it will be critical when it comes to selling their premium content. They must ensure that they are choosing the right CDN method to ensure the best experience for the end user and the most cost effective method for themselves. Being knowledgeable in CDNs will allow content owners to maximise profits and customer satisfaction.

John Malchov, content delivery network expert of SpaceCDN.com