Most of you have read something about classical approaches to CDN: anycast, GeoDNS or just a plain web server with enabled cache layer. And it works great for common web applications — reading text or scrolling through doge memes. But when it comes to video streaming — that’s a whole new story!

Scale always brings new challenges. Having a dozen nodes serving your users without fail — we’ve been there. Moving up to horizontal scaling using different locations in our data centers — long gone. Now we have a massive CDN with external locations serving hundreds of thousands of users simultaneously, distributing terabits of media data per second. In my talk I’ll explain the reasoning behind our CDN architecture and tell you how a basic automated systems algorithm can keep you sane.

In this talk I will:
— introduce basic network-related problems of our video streaming platform;
— talk about why standard CDN building approach is no good for our system;
— iterate through our approaches on distributing traffic via our CDN locations;
— show how we use the PID-controller algorithm to control traffic flow.