Document game networking principles (#787)

Relates to #462.

docs/src/multiplayer/connector/README.md

@@ -11,7 +11,39 @@ means of binary data exchange.
 (peers), the server either receives and interprets the data, or transmits it to
 other clients connected to the same game.
 
+Game participants exchange [messages](./encoding.md) through a game server. For
+efficiency, multiple messages may be grouped into a single
+[package](./protocol.md#package), and the messages are buffered and flushed at
+the end of each game update (frame). The buffering is independent for
+unreliable, unordered, and semi-ordered packages, with their buffers being
+flushed in the respective order.
+
 The main server listens on port 8082, which is designated solely for server
 control messages such as game initiation requests. Upon the creation of a new
 game, a unique sub-server, listening on a different port, is started. It is
 within these sub-servers that clients exchange data among themselves.
+
+## Principles
+
+Game networking is designed in such a way that complete game determinism is not
+required for certain aspects, such as entity movement. It is assumed, however,
+that the divergence among individual clients is negligible in the short term
+(on the order of several seconds). This approach simplifies movement simulation
+but comes at the cost of the need for regular synchronization and higher
+network bandwidth requirements.
+
+All clients simulate all game activities while receiving updates to correct any
+possible simulation divergence. Each action has its authoritative owner,
+corresponding to the client that is locally controlling the entity responsible
+for the action, whether through a human player or AI. The owner sends a
+synchronization message, which is respected by the other clients. For instance,
+an entity damage action (a decrease in health) is owned by the client
+simulating the entity that causes the damage (for example, by firing a laser
+cannon).
+
+Whenever possible, messages are sent in unreliable mode. This method of data
+exchange consumes fewer resources but does not guarantee delivery or ordering.
+For instance, entity movement synchronization occurs unreliably. This approach
+is both possible and preferable because the position of each entity, out of
+possibly thousands, is regularly updated, and messages that reference
+non-existent entities are disregarded.