When launching multi-user editing sessions using nDisplay, Unreal Engine automatically creates a local server to host multiple editor users simultaneously.
In the following document you can read about the multi-user server connection logic for launching virtual production projects using nDisplay in Unreal Engine.
Multi-User Connection Logic
When launching a virtual production project using nDisplay for the first time, you can use the Quick Launch tool to automatically launch a local server multiple users can connect to.
When launching your project using nDisplay for a second time, Unreal Engine automatically reconnects to the existing local server and reuses the existing multi-user editing session if the editor is already operating in a session. If the editor is not operating in an nDisplay multi-user editing session, Unreal Engine creates a new multi-user editing session on the local server.
You can also build your own custom multi-user server to host an nDisplay multi-user editing session, that multiple users can connect to locally or using a network connection.
When attempting to join a network-based multi-user server, Unreal Engine checks if the editor is already in a multi-user editing session. If the editor is operating in an editing session, Unreal Engine joins the generated multi-user server and session. If the editor is not already operating within an nDisplay multi-user editing session, Unreal Engine closes the local multi-user server, ignores the network-based multi-user server, and launches a new server locally.
You can use the following diagram to better understand the Unreal Engine Multi-User (MU) connection behavior:
For more information about getting started using multi-user editing sessions, refer to the Multi-User documentation.
For more information about launching virtual projects using nDisplay, see the nDisplay documentation.