Eventual Consistency

Fusion relies on the transfer of game state from an authority to all of the other clients. The state contains everything needed for the client to replicate the game state locally. An Eventual Consistency model is used, which minimises the data which must be transmitted, as it sends only the changes in the data, for NetworkObjects which have changed.

By default Fusion uses a version of Eventual Consistency called Full Consistency. This ensures all [Networked] properties on a single NetworkObject arrive on clients in the same tick, providing consistent data on a per-object basis. It is possible to opt-in to classic Eventual Consistency mode where [Networked] property changes are separate, even on the same NetworkObject and may not all occur on the same tick. For this set the SimulationConfig.ObjectDataConsistency to Eventual in code.

Interest Management

It possible to further reduce bandwidth requirements by utilizing the API to controlling what data is sent to each player; this is commonly referred to as "Interest Management".

This can dramatically reduce the amount of data sent across the wire without affecting the individual player's perception of the world. This is especially true in large game worlds with many players, where interest management is often essential in order to make the game playable.

See the Interest Management documentation page.