Resolved How to keep Relay connection alive using NGO?

Hi there,

This page should help explain setting up Relay with NGO: https://docs.unity.com/relay/relay-and-ngo.htm

Specifically, you would need to authenticate the player, allocate the Relay server and get the join code, and set the Relay server data. You would then need to set the UTP protocol type as Relay Unity Transport (the details for each step can be found on the page).

You would then call NetworkManager.Singleton.StartHost(), which should take care of binding, listening and keeping the Relay connection alive.

I hope this helps!

 

Hi again,

I just ran into the same issue but it also cleared up for me after a few retries (I believe this clears out any cached data).

Glad it's working!

 

Hey @SirKnightDragoon,

It sounds like from what you're describing that you are running into an issue you've seen before with a host / client trying to connect to the same machine. There is a thread here where @UnityKip talks about it in detail and provides a workaround.

 

Sorry to hear that. Luckily there is some troubleshooting that can be done to figure out where exactly the issue is stemming from. First, to make testing a little easier, you may want to check out the 3rd party ParrelelSync package. Note that although this isn't officially supported, many users find it extremely useful when working with Relay.

Try installing the Relay sample "Simple Relay Sample" via the package manager under the Relay package. If you get a 403 error while trying to click any of the buttons from top to bottom, most likely your project isn't linked properly or Relay isn't enabled through the developer portal. It should be noted that this sample does not actually connect to an instance, but rather just tests commands to the API up to creation.

If that is working fine, try installing the Interactive Relay Sample (using UTP). This allows you to create builds in which you can create a host and client instance and test connections between them. This rules out any sort of firewall or configuration issue).

If both of those work, then the root cause is most likely that the network manager is not being properly started. Once connected, the Network Manager / NGO will keep your connection alive for you, so from what you are describing it sounds like that is the issue. If you verify that it is being properly started or you are still having issues, I recommend submitting a support ticket and including your project ID and allocation ID (somewhat sensitive, please do not post here). That way I can take a look at what is happening on the backend to confirm if the host manager is connecting.

 

Hi @SirKnightDragoon,

I wanted to add-on to the recommendations from @BrandonUnity3D to quickly note that I ran into a similar issue as you in my own testing. In my case, I was calling Relay.Instance.JoinAllocationAsync(joinCode) on the Host after running NetworkManager.Singleton.StartHost(). I believe this might be the same setup that is happening in your project.

The issue is that NetworkManager.Singleton.StartHost() implicitly joins the Relay as a Client for the Host. You can review the NGO code handling this here.

For me, the fix was to remove the superfluous JoinAllocationAsync() call on my Host. After that, I was able to properly host a relay and did not see any more timeouts.

Good luck with your development and please open a ticket if the issue persists!
-Kip

 

I would recommend only creating an allocation once you're ready for the host to connect to it. You can think of the Network Manager as a utility that makes working with UTP easier, and UTP as a library to make it so you don't have to work with low-level networking utilities. Once an allocation is created and listening for network traffic, it just needs some type of activity in order to stay in an unexpired state. If you are using the network manager, once it is connected, it will automatically take care of this for you. If instead, you are using UTP directly, you can use the process described under Relay and UTP / Keep the Relay connection alive. I suppose it would be theoretically possible to directly send network traffic to the allocation, however, I would advise against this. Creating and connecting to the allocation is usually very fast, so regardless of if you are using the Network Manager w/ UTP or UTP by itself, those two functions should be done about the same time.

 

Hi @sschmid_unity

I can see a few issues in your example, however, without seeing all of the code or the project we may need additional information to solve any issues you're running into. I'll try to get through all of it below.

The first step to resolving this is to check the CreateLobby call:

Code (CSharp):

1. currentLobby = await CreateLobby(game.JoinCode, lobbyName);

You'll want to confirm that this call correctly creates a Lobby and assigns the Join Code to the Host's Player.ConnectionInfo (Player Update Example).

Next, your client join code suggests that your Host may also be attempting to connect to the Relay created by HostGame(). If this is accurate, then your Relay will lose its Host when you call:

Code (CSharp):

1. NetworkManager.Singleton.StartClient();

I describe this issue in the post above, but basically, StartHost() implies StartClient(). The host of a Relay allocation should NOT call both. The resulting 10s expiration would then be expected behavior per Relay's heartbeat requirement.

This error is probably from Netcode for Game Objects when a client has not received a network packet from a host. This should be resolved once the Relay and Lobby implementations are correctly in place. However, please feel free to post the full error here if it happens again following our troubleshooting.

This is expected behavior. Only the host should receive this callback. This callback is meant to indicate to the host that a client has joined, not for a client to know that it has established connectivity. You can use NetworkManager.IsConnectedClient() to verify if a client has an active connection.

Netcode for Game Objects will handle the pings to the Relay server. However, you can see an example of how to keep a Relay server alive here. Handling the ping at the transport level is here.

If you need further assistance, please consider opening a support ticket through the Unity Dashboard under Help & Support -> File a Ticket -> Multiplayer -> Relay.

Regards,
-Kip