When you press play, Netflix's video doesn't come from the cloud

transcript

You press play on Netflix. The video doesn't come from the cloud. It comes from a box inside your internet provider. Or right next to it.

Friday, 8 PM. About 10 million people streaming at once. Each one pulling about 5 megabits a second. That's 50 terabits a second. That number picks the architecture.

Stream it from the cloud? Ruinously expensive. And far from most viewers. Distance means slow starts and buffering. Rent a CDN? Illustrative list prices: 2 to 5 cents a gigabyte. On about an exabyte a day? 7 to 18 billion dollars a year.

So Netflix built its own boxes, inside internet providers. Over 18,000 of them. One box: 120 terabytes, about 200 gigabits. Around 40,000 streams. Over 90 percent of requests hit it.

You press play. AWS checks your entitlement and device, and sets up DRM. It hands back a manifest. That's the last thing the cloud does. The manifest points your player at the box in your ISP. Every video byte comes from there. The cloud never streams video.

Small requests that must be correct? The cloud. Fifty terabits of video? Right next to you. The cloud decides. The ISP delivers.

Full breakdown in the lecture.