I'm sure the answer could be found in this repo somewhere but its above my head- does aoe2 DE rely mostly on p2p for multiplayer? I assume it does and the regional servers are just used for matchmaking, and all the actual game logic is running on the clients. I base that on the fact that map hacks are possible and that one player lagging lags the game for everyone, but there are often conflicting claims when it's brought up on aoe forums

If you haven't read it, there's a great paper on the netcode of the originals: https://zoo.cs.yale.edu/classes/cs538/readings/papers/terran...

I'd be surprised if the definitive editions changed the design significantly enough to move the netcode away from P2P, but I don't know of any actual information on it.

AFAIK, it's server-based rather than p2p for DE, but the way it works is all clients/servers simulate the world in lockstep and hold a full copy of the state. That's what makes map hacks possible.

You don't need anything paxos-like for this, the game desyncs and stops if any machine messes up but you can usually restore from a save point in that case.

In professional tournament games a server is chosen that lies between the two players. For example, a Brazil-China match might be played in an EU server.

Given this, I suspect the server is used as a central source of truth between the clients where all game data goes through the server, with all the calculations still being done client-side.

That was the old one , the DE version lags only for the player with poor network ( cpu performance stutter of one player affect all players though )