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Use Relay with Netcode for GameObjects

Integrate Relay with Netcode for GameObjects using the unified Multiplayer Services SDK.
Read time 3 minutesLast updated 14 hours ago
Relay works seamlessly with Netcode for GameObjects, which is a Unity package that provides networking capabilities to 
GameObject
and 
MonoBehaviour
workflows. This tutorial demonstrates how to use Relay with Netcode for GameObjects.

Installation and configuration

  1. In the Unity Editor's Package Manager, select Unity Registry.
  2. Search for the following package: 
    com.unity.services.multiplayer
    .
  3. Select the package, then Install. Refer to Package Manager.
  4. Repeat for 
    com.unity.netcode.gameobjects
    .
You must first configure your Unity project for Unity before using Relay with Netcode for GameObjects. Refer to Get started with Relay to learn how to link your project in the project settings.

Set up the NetworkManager

After installing the packages, you can now set up the 
NetworkManager
:
  1. Add a new GameObject to your scene.
  2. Add the NetworkManager MonoBehaviour.
  3. In the MonoBehaviour Properties, select the UnityTransport transport. After selecting UnityTransport, you’ll see a 
    MonoBehaviour
    called Unity Transport (script) at the bottom of the components list.
  4. Set the Protocol Type of the new component to Relay Unity Transport.

Host player

The 
StartHostWithRelay
function shows how to create a Relay allocation, and request a join code. This function requires the maximum number of connections the allocation is expecting and the host player connection type. The connection type must be one of the following options:
  • udp
  • dtls
  • wss
Refer to DTLS to learn more about DTLS encryption, and to Web Platform Support to learn about using 
wss
. This code should be adapted to your needs to use a different authentication mechanism, a different error handling, or to use a different connection type. Similarly, you can call 
StartServer
instead of 
StartHost
to start a server instead of a host. 
public async Task<string> StartHostWithRelay(int maxConnections, string connectionType){    await UnityServices.InitializeAsync();    if (!AuthenticationService.Instance.IsSignedIn)    {        await AuthenticationService.Instance.SignInAnonymouslyAsync();    }    var allocation = await RelayService.Instance.CreateAllocationAsync(maxConnections);    NetworkManager.Singleton.GetComponent<UnityTransport>().SetRelayServerData(AllocationUtils.ToRelayServerData(allocation, connectionType));    var joinCode = await RelayService.Instance.GetJoinCodeAsync(allocation.AllocationId);    return NetworkManager.Singleton.StartHost() ? joinCode : null;}

Joining player

When your game client functions as a joining player, the relay join code, retrieved in the previous step when the host created the allocation, must be passed to find the allocation. The following code samples show how to join an allocation with a join code and configure the connection type. The connection type must be one of the following options:
  • udp
  • dtls
  • wss
Refer to DTLS to learn more about DTLS encryption, and to Web Platform Support to learn about using wss. 
public async Task<bool> StartClientWithRelay(string joinCode, string connectionType){    await UnityServices.InitializeAsync();    if (!AuthenticationService.Instance.IsSignedIn)    {        await AuthenticationService.Instance.SignInAnonymouslyAsync();    }    var allocation = await RelayService.Instance.JoinAllocationAsync(joinCode: joinCode);    NetworkManager.Singleton.GetComponent<UnityTransport>().SetRelayServerData(AllocationUtils.ToRelayServerData(allocation, connectionType));    return !string.IsNullOrEmpty(joinCode) && NetworkManager.Singleton.StartClient();}

Note about Unity Web platform support

To use Relay with Netcode for GameObjects in Unity Web platform supported game, upgrade the Unity Transport Package to 2.0.0 or later and configure the Unity transport component to use Web Sockets. Using the above code snippets, pass wss as 
connectionType
and use the following to 
SetRelayServerData
: 
NetworkManager.Singleton.GetComponent<UnityTransport>().SetRelayServerData(AllocationUtils.ToRelayServerData(allocation, connectionType));NetworkManager.Singleton.GetComponent<UnityTransport>().UseWebSockets = true;