P2P. It’s a DHT model just like BitTorrent. And uses a 2-way hole punching method to get through any firewall. It’s pretty slick. It’s really an extension of BitTorrent when you look at its history and the development of it. This has been a 10+ year project continued from previous ones that were incrementally making BitTorrent more data agnostic so you could do anything with it, rather than only serve static files.

What Guy Swann said below + it is all peer-to-peer, you are the server and the client.