Redesign network model... again

[ryan]

Asking users to forward a TCP and UDP port is still a bit of a hassle for players who just want to get going. Therefore a new model is required so that players can "just play" from anywhere, anytime.

This model should be based loosely on other contemporary client-server models, using direct connections when possible (if the user has forwarded ports).

A possible idea is as follows:

• If a user has not forwarded any ports, all of their data is relayed through the game server
• If a user has forwarded ports, each player should be able to directly connect to that player
• If no users in a game have forwarded ports, central servers that can host a game and pass packets back and forth must be available and online, and the IMR must be able to select the best available server for the players for a game under these conditions

This will be a fairly extensive rewrite involving the client, the IMR, and a standalone game server will need to be created also.

[ryan]

Actually, I was unaware of the reliability of this method, but UDP hole punching seems to be an adequate solution for approximately 80% of NAT setups [1]. While that's not good enough for a solution on its own, a good approach may be to have an available server to work as a relay for hosts that are unable to hole punch. As a result lag for those clients will be increased significantly, but it will work.

[1]  http://www.brynosaurus.com/pub/net/p2pnat/

[ryan]

Ok, I found my clipboard and sketched out what I want to do. File is attached.

[ryan]

(In #165) Use new Dedicated Server component, and new version, and update tickets that this is blocking.

[ryan]

This should use boost::asio, like the dedicated server (#165).