[glob2-devel] Finalized Design Idea for YOG

[Bradley Arsenault]

I've already begun implementing the new and improved networking engine
so I'm going to quickly lay it out:

1) Glob2 will use SDL_net, and TCP sockets
  - Glob2's current system implements TCP functionality on top of
UDP, because of the demand for absolute sychronization at every frame,
TCP functionality is nesseccarry, and no better way than to use actual
TCP.

2) The NAT problem is solved by YOG routing. Me and Leo considered
this a decent option.
   - Glob2 sends barely any network traffic (at most 2 kb/s per
client, practically nothing considering our webserver had multi
gigabytes per day)
   - Right now there are hardly ever net games unless they where
pre-organized. The system can scale too. If glob2 suddenly becomes a
hotspot of online activity, there can be yog-usa1, yog-europe1,
yog-europe2, done by YOG redirection

3) The YOG server is built right into glob2 and shares code with the client.
   - For LAN games, the person would run feature-reduced YOG on their
local system
   - (This system would use a sort of moduleapproach, where there is
password based login system and there is anonymous login system. There
is a game list system, and there is a system where all connected users
are part of the same game.)
   - As well, for people without NAT issues, they can offer to host
the game themselves, using the same principle, the main YOG will just
redirect, to take the load off the main YOG

4) I've currently got three classes, NetMessage, NetConnection, and
NetListener. They all wrap SDL_net at a fairly low level. I have made
the choice to use boost::auto_ptr for all Net engine stuff. There are
allot of dynamically allocated objects that are created and destroyed
frequently in different parts of the code.
   - NetListener listens for incoming connections, and can create a
NetConnection if there are any
   - NetConnection interfaces with SDL_net, wrapping it with a
NetMessage based system. It queues messages in a non blocking manner.
   - NetMessage is an abstract base class. It is similar in theme to
Order. I like the design of Order classes myself.
   - The one subclass of NetMessage (right now, many to come), is
NetSendOrder, which bassically wraps the Order class

5) The system is going to be optimized for low bandwidth consumption
   - This is critical, it reduces latency, reduces the load on our
servers, and in general reduces the load on the internet as a whole.
   - Packets may be compressed just before being sent to SDL_net if
its found effective

** this part i'm not to sure about quite yet **

6) NetMessage will use a cascading system. At each level, some
different part of glob2 will filter out the messages it handles. 95%
of them will be handled by the net code itself, but some of them may
cascade further.

--
Really. I'm not lieing. Bradley Arsenault.