This document is about the Quake2 network protocol from a quake dll perspective. That is, it lines up the principles and lists the opportunities of the network protocol for adding effects to the game.
The server communicates with the clients through network packets. Once broadcasted the clients will update their screens to reflect the changes made to the world.
Packets are created in the code by writing bytes, shorts, and positions to the game API and then submit the packet using the multicast or unicast function of the game API.
You can use, or may have to use, these functions when you want to display effects like sparks and explosions from your game DLL.