Good multiplayer networking approaches

In the past I’ve searched for resources on multiplayer networking. Not the MMORPG type (which is more of a database/load-handling approach), but the good old Quake stuff. The 24-player online FPS. That’s what I wanted to know. So here are some of the most useful stuff to get anyone started on the matter.

http://trac.bookofhook.com/bookofhook/trac.cgi/wiki/IntroductionToMultiplayerGameProgramming

https://gafferongames.com/networking-for-game-programmers/udp-vs-tcp/

https://gamedev.stackexchange.com/questions/21025/what-advantages-are-there-to-the-one-port-per-client-approach-for-a-multiplayer?rq=1

The answers already at gamedev.stackexchange answered nearly all of my questions. It’s a great resource.