I just found out that Battle Bit Remastered exists and it supports 254 simultaneous players per game.
I am wondering how that is even possible. Does anyone know of any details on how they achieved it? Are there any resources for making a networking engine capable of supporting that many players?
You just have to be very well optimized. Probably spreading out data validation across many frames. Keeping the network overhead per player low. Using events and stuff with verification instead of syncing files when not needed.
Other methods you can use are p2p file sharing or even distributed verification among client machines to take load off the server. You probably also want to keep all data in a single stream per player to avoid overloading the routers CPUs, with hundreds or thousands of connections.