I like the distributed physics sim load approach, but, when scaling, internet bandwidth worries me. Since you’re maintaining connections with three players simultaneously, does that mean that you’re actually aiming for a 192kbps user internet connection instead of 64kbps? Or does this network not scale this way.

In the end, I have decided at least for my home project that I am moving toward a dedicated client/server approach instead. Many reasons, simplicity, late join, anti-cheat, higher player counts etc.

The dedicated server owns the white objects and simulates them, the colored objects are under authority of the client and are “committed” by the client to the server. If the server accepts this commit, then the dedicated server owns the database of all object state so late joining becomes much easier.

Alternatively, you could have a smaller world and like you say, not stream in prior-state on a need to know. Consider using a deterministic lockstep networking model instead, it may be better for your game.

cheers

You mentioned that the 3rd and 4th player need to ask for confirmation from player 1 and 2. If the world is persistent, and player 2 sends updates to player 1, then wouldn’t late joiners only need confirmation from player 1? He was there the entire time right?

Essentially player 1 knows everything, and player 2 only knows about the area around him, as confirmed by player 1. Why would you ask player 2 for anything but what he currently owns? Player 2 may not have ever been around player 3′s area. What would player 2 know?

And touching a subject that wasn’t covered… What if player 1 leaves? Should the entire world state be sent to player 2? At this point, I’m having a hard time justifying streaming on a need-to-know basis. If player 1 leaves, the confirmed world state goes with him. Any way around this?

Thanks!
Joe

cheers

I work for an indie MMO developer in the UK, and I was wondering what you’d advise for an MMO client-server model with respect to physics? It will affect some fairly important aspects of the game, we have a few ideas, but just wondered what your take would be.

Thanks for your time, and for this great series of articles, I really ought to donate again soon!
Cheers
Joe

Your demo got me thinking about how Firefall would implement their 100 player + FPS server. The only downside is that you rely on the peer to peer networking model to communicate state (a nono for FPS games due to cheating). I was thinking maybe clients connecting to multiple servers: peer to peer authoritative servers (like http://pvs.uni-muenster.de/pvs/forschung/edutain/material/From_a_Single-to_Multi-Server_Online_Game_A_Quake_3_Case_Study_Using_RTF_author-prepared.pdf ).

It seems to be quite complex, but it could solve the cheating issue.

Dunno, just thinking out loud.

I’ve put the first version of the instructions and code up on github, here: http://github.com/malvim/fiedlerscubes, if you want to take a look.

Thanks!