Netflix and YouTube CDN Architecture

Netflix video distribution has two major components: the Amazon cloud and its own private CDN infrastructure.

Content ingestion.

Before Netflix can distribute a movie to its customers, it must first ingest and process the movie. Netflix receives studio master versions of movies and uploads them to hosts in the Amazon cloud.

Content processing.

The machines in the Amazon cloud create many different formats for each movie, suitable for a diverse array of client video players run- ning on desktop computers, smartphones, and game consoles connected to televi- sions. A different version is created for each of these formats and at multiple bit rates, allowing for adaptive streaming over HTTP using DASH.

Uploading versions to its CDN.

Once all of the versions of a movie have been created, the hosts in the Amazon cloud upload the versions to its CDN. Netflix distributes by pushing the videos to its CDN servers during off-peak hours

Similar to Netflix, Google uses its own private CDN to distribute YouTube videos, and has installed server clusters in many hundreds of different IXP and ISP locations. From these locations and directly from its huge data centers, Google distributes YouTube videos [Adhikari 2011a]. Unlike Netflix, however, Google uses pull caching, and DNS redirect,. Most of the time, Google’s cluster-selection strategydirects the client to the cluster for which the RTT between client and cluster is the lowest; however, in order to balance the load across clusters, sometimes the client is directed (via DNS) to a more distant cluster [Torres 2011].

Several million videos are uploaded to YouTube every day. Not only are You- Tube videos streamed from server to client over HTTP, but YouTube uploaders also upload their videos from client to server over HTTP. YouTube processes each video it receives, converting it to a YouTube video format and creating multiple versions at different bit rates. This processing takes place entirely within Google data centers