What's the Technical Definition of a Tail Scale Relay?

Every tail scale node has a connection to all of the derp servers. And through process of, you know, latency testing, it figures out which connection is the fastest and the lowest latency. Because everything is connected to every derp, you can have two people with different home derps getting their packets relayed to other clients from different derps. It's one of the most weird distributed systems type things that I've ever seen.