So I know how a CDN works in principal and how it works from a customer's perspective. My question is more about the root of how they work, the routing. My limited knowledge points to just some fancy DNS work. Something along the lines of Geoipdns. Is that about right?
So if I wanted to create my own little CDN, the practicality of which is beyond this question, and I had servers on west coast, central and east, then all I would need is my own dns servers that looked at the incoming ip, mapped its location and routed accordingly, yes?