Networking Models
This page discusses the varius networking models and architectures used in games and what Fish-Networking uses.
Client-Server Architecture
The client-server model is the most widely used approach in multiplayer networking. In this model:
Server: The authoritative instance of the game. It manages game logic, synchronizes game state, validates player actions, and handles communication between clients.
Client: A player's instance of the game. It sends input to the server and receives updates about the game state.
There are two main types of servers:
Dedicated Server
The server runs as its own process, separate from any player. It’s more secure and scalable, commonly used in competitive or large-scale games.
As you can see from the above diagram, the clients (players) are all connected directly to the server and communicate with it instead of with each other.
Host (Listen Server)
The server and one of the clients run in the same process. This is common in smaller games or development environments.
The above diagram demonstrates how the listen server is similar to the dedicated server model where all clients connect directly with the server, but unlike the dedicated server, the listen server is also acting as a client (player).
FishNet supports both dedicated and host server models out of the box.
Peer-to-Peer (P2P)
In peer-to-peer networking, each player (or peer) connects directly to others without a central server. This reduces latency and server costs but comes with challenges:
Poor security and cheating prevention
Difficult to synchronize game state reliably
NAT traversal issues
P2P is rarely used in modern real-time multiplayer games, especially competitive ones, due to these drawbacks. FishNet does not use P2P, as it is designed around the client-server model for reliability and security.
Relay Servers
Sometimes clients are unable to connect directly to the server due to NAT (Network Address Translation) or firewall restrictions. A relay server acts as a middleman to forward traffic between clients and the server.
Relay servers:
Allow connectivity when direct connections fail
Introduce additional latency
May be used as a fallback or for web-based games
Fish-Networking supports multiple third-party relay services including Unity's Relay, Edgegap's Distributed Relay, Photon Realtime, Epic Online Services' Relay Service, and Steam Datagram Relay.
Host Migration
When using a listen server, the host leaving the game would cause all players to leave the game; Host migration is a feature for maintaining game sessions in the event the current host disconnects or experiences network issues. It enables a new host to be elected from the remaining connected players, minimizing disruption and ensuring the game session can continue seamlessly.
Fish-Networking doesn't yet have built-in host migration, but it is a feature that may be added in the future.
Last updated