Distributed authority topologies
The distributed authority network topology is one possible network topology available within Netcode for GameObjects. Distributed authority games use the distributed authority model.
The traditional client-server network topology has a dedicated game instance running the game simulation. This means all state changes must be communicated to the server and then the server communicates those updates to all other connected clients. This design works well when using a powerful dedicated game server, however significant latencies are added when communicating state changes with a listen server architecture.
Note
The distributed authority service provided by the Multiplayer Services package has a free tier for bandwidth and connectivity hours, allowing you to develop and test without immediate cost. Refer to the Unity Gaming Services pricing page for complete details.
Considerations
Using a distributed authority topology is typically not suitable for high-performance competitive games that require an accurate predictive motion model. The distributed authority model successfully addresses a lot of visual and input-related issues, but does have some limitations:
- Because authority and ownership of objects is distributed across clients, there's typically no single physics simulation governing the interaction of all objects. This can require approaching physics-related gameplay differently compared to a traditional client-server context.
- Depending on the platform and design of your product, it can be easier for bad actors to cheat. The authority model gives more trust to individual clients. Evaluate your cheating tolerance when developing with distributed authority.
Session ownership
When using the distributed authority topology, it's necessary to have a single dedicated client that's responsible for managing and synchronizing global game state-related tasks. This client is referred to as the session owner.
The initial session owner is the first client that joins when the session is created. If this client disconnects during the game, a new session owner is automatically selected and promoted from within the clients that are currently connected.
IsSessionOwner
To determine if the current client is the session owner, use the IsSessionOwner property provided by Netcode for GameObjects. This property is available on the NetworkManager.Singleton instance and returns true if the local client is the session owner.
public class MonsterAI : NetworkBehaviour
{
public override void OnNetworkSpawn()
{
if (!IsSessionOwner)
{
return;
}
// Global monster init behaviour here
base.OnNetworkSpawn();
}
private void Update()
{
if (!IsSpawned || !IsSessionOwner)
{
return;
}
// Global monster AI updates here
}
}
You can use this property to conditionally execute logic that should only run on the session owner, such as managing global game state or handling session-wide events.