OTT CDN – What Content Delivery Network Is And What It Does
OTT CDN – Content Delivery Explained
What is OTT CDN and what this term means? There are different terms used in the IPTV / OTT industry that can mean different things to different people and the same is true for the term OTT CDN. The best way to understand what somebody means by it is to know how it works.
What does CDN mean?
CDN means content distribution network. At first CDN providers were caching HTTP/web traffic and distributing files such as games, firmware, etc. With the expansion of video streaming, all CDN providers extended their support to video streaming as well.
CDN platforms for video content delivery
As the OTT term is tightly related to video streaming over the internet, the first thought about OTT CDN is CDN streaming for video. Originally, CDN was reserved for cloud-based service and there are many global providers such as Amazon, Akamai, Cloudflare, Fastly, etc.
OTT CDN servers reaching connected devices
CDN streaming is not just for OTT content…
Today, some people may use the term CDN for systems that do video streaming although this is not technically correct. Such a system is called a streaming server, streamer, or origin server. If a few years ago CDN was used only for the cloud-based service, today some vendors use it also to describe their software and their technology, even though they don’t sell the service but only a platform.
….and streaming platforms still need OTT CDN resources
When buying a platform, the operator still needs to organize a transport network with the required bandwidth in order to stream video to end users, while traditional CDN would provide just that, bandwidth in order to reach your users globally.
What is a private CDN?
The best OTT platforms provide not only MW/cms but also a streaming part and the most advanced vendor support option to use their streaming servers to build private CDN. Private CDN in this case means a number of edge streaming servers installed in different locations/data centers of the operator within the IP network owned by the operator.
Benefits of private CDN
With this approach, an operator is able to serve much higher capacity as streaming bandwidth is distributed across different locations, users are served from nodes closer to them which guarantees shorter latency and better user experience and most importantly operator does not need to pay anything to external CDN services for bandwidth because everything stays in operator IP network.
How streaming servers usually work
A streaming server is a web server that is dedicated to delivering live or on-demand video content to the user’s device that is connected to the internet (computer, smart tv, or mobile device).
Origin encrypts, records, and forwards the content
Let’s explain further how streaming server usually works and which components it has. The main component is the origin which receives HLS or dash streams from the transcoder or packager and prepares them for delivery to end users. It encrypts these streams if required. It also records streams for the Catch-up TV and nPVR service and stores it on the storage. Origin will also store all on-demand content in the format ready to be streamed. Origin will not stream directly to the end users but will forward content to edge streaming servers from where it is streamed to end users.
Edge streaming servers enhance the delivery quality
Edge streaming servers can be installed on the same location as the origin or in some cases even on the same server. Or edge servers can be distributed across the network to be closer to the end users. In this scenario, we talk about the private CDN.
Video stream gets delivered through a CDN
When a service provider does not have its own IP network and wants to stream content globally, it will have an origin server to prepare and control the streaming of the content but will use some global CDN service such as Akamai for distribution. In such case, an OTT CDN service will charge you for each transferred GB, so this can be quite costly, especially for live tv service.
