Question

I have have a small prototype game in java where players can build their own levels, and then set themselves up as a server to invite other players into their world. All in all its been a good introduction into the world of networking.

For the final product however, I have been thinking about expanding this so that I can have a central server with a central world. This would allow players to meet up inside the central game world, and then invite each other into their own worlds or whatever.

Ideally, when players go into the world of another player, then all of them will be effectively disconnected (except perhaps from a universal chat channel) so that the player whos world the group entered becomes new server to the the other players. This set up will hopefully give the game the open ended continuity of an MMO, but also keep the traffic on my server at a minimum since players will primarily be off hosting their own areas.

I am considering that its highly likely that the average player will not have a static IP – is this a problem? Are there security risks with delivering the connection information of one client to another? Are there any other problems or impossibilities I should be aware of before start attempting this?

Answer 1

Interesting idea, I looked at a similar concept for a couple of game projects.

I see three big problems:

• Difficulty of establish P2P connections between players. You might be best trying to adopt an existing P2P networking tool and adapting it for your game rather than writing something from scratch, but either way there will be challenges (dynamic IPs, firewalls etc.). You may be able to use something like JXTA.
• Whoever is nominated as the server can “cheat” very easily, and you’ll have limited ways of stopping this as you don’t control the server any more. You’ll have to make sure you plan for this eventually – you can guarantee that some players will try to abuse it if your game gets popular enough.
• The mechanics of determining who joins each game world – could get quite complex, what happens on disconnect for example? How do you ensure players know about each world? Do they need to join at the same time? etc. etc.

None of these are totally insurmountable but it will be a challenge to get it all working smoothly….