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Unity Netcode Bandwidth Consumption

Discussion in 'Multiplayer' started by guram58chaganava, Feb 27, 2023.

  1. guram58chaganava

    guram58chaganava

    Joined:
    Jul 8, 2020
    Posts:
    5
    My project involves data synchronization. To accomplish that I use Netcode for Gameobjets and Unity Relay service. In the project, there is one 3D human model which is NetworkObject. Depending on the specifics of the project, it is important to synchronize the least amount of data. However, the measured result significantly missed my expectations. Let me explain in more detail:

    I am sending the data using NetworkVariable. The first NetworkVariable contains one Vector3 and the second one contains CustomData object that holds 5 variables of type short. All this comes out to a total of 22 bytes. Because together with the sending, there is also the receiving, we get 44 bytes per frame. Let's say there is 30 FPS, so data usage per minute is 44X30X60=79 200 B = 77,3 KB = 0,076 MB. In addition to this, some data is needed for protocol implementation, although as a rule, their amount is not large. But, after testing the app, data usage came out to about 0,5 MB per minute. I can't figure out why is there such a big difference between my calculation and the measurement. Do you have any idea what can be the reason for such a big bandwidth consumption? Am I doing something wrong or is this result normal?

    Below is the test program code that handles data synchronization. It is attached to the 3D human model.

    Thank you in advance!
    Code (CSharp):
    1. public class NetworkSync : NetworkBehaviour
    2. {
    3.    
    4.     private NetworkVariable<Vector3> myVector;
    5.     private NetworkVariable<CustomData> myData;
    6.     private AvatarDrivers AvatarDriversObject;
    7.    
    8.     private void Awake() {
    9.         myVector = new NetworkVariable<Vector3>(writePerm: NetworkVariableWritePermission.Owner);
    10.         myData = new NetworkVariable<CustomData>(writePerm: NetworkVariableWritePermission.Owner);
    11.         AvatarDriversObject = transform.GetComponent<AvatarDrivers>();
    12.     }
    13.  
    14.     public override void OnNetworkSpawn(){  
    15.         //...//
    16.     }
    17.  
    18.     void Update(){
    19.         if (IsOwner){
    20.             Debug.Log("send " + System.DateTime.Now.ToString("hh.mm.ss.fff"));
    21.             myVector.Value = AvatarDriversObject.rightElbowTarget.position;
    22.             myData.Value = new CustomData{
    23.                 posData = AvatarDriversObject.wrist_r.position,
    24.                 rotData = AvatarDriversObject.hand_r.rotation.eulerAngles
    25.             };
    26.         }else{
    27.             Debug.Log("receive " + System.DateTime.Now.ToString("hh.mm.ss.fff"));
    28.             Debug.Log("myVector: " + myVector.Value);
    29.             Debug.Log("myData.Value.posData: " + myData.Value.posData);
    30.             Debug.Log("myData.Value.rotData: " + myData.Value.rotData);
    31.         }
    32.     }
    33.    
    34.     private struct CustomData : INetworkSerializable {
    35.        
    36.         private short pos_x, pos_y, pos_z;  
    37.  
    38.         private short rot_y, rot_z;  
    39.        
    40.         internal Vector3 posData {
    41.             get => new(pos_x, pos_y, pos_z);
    42.             set {
    43.                 pos_x = (short)value.x;
    44.                 pos_y = (short)value.y;
    45.                 pos_z = (short)value.z;
    46.             }
    47.         }
    48.        
    49.         internal Vector3 rotData {
    50.             get => new(0, rot_y, rot_z);
    51.             set {
    52.                 rot_y = (short)value.y;
    53.                 rot_z = (short)value.z;
    54.             }
    55.         }
    56.  
    57.         public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter {
    58.            
    59.             serializer.SerializeValue(ref pos_x);
    60.             serializer.SerializeValue(ref pos_y);
    61.             serializer.SerializeValue(ref pos_z);
    62.            
    63.             serializer.SerializeValue(ref rot_y);
    64.             serializer.SerializeValue(ref rot_z);
    65.         }
    66.     }
    67.  
    68. }
     
  2. CodeSmile

    CodeSmile

    Joined:
    Apr 10, 2014
    Posts:
    5,511
    Apparently you did not account for time synchronization. But I can't say how much that will be.
    There's probably other stuff going on, such as connection state management, especially when it comes to relay service there will probably be some keep-alive traffic happening. And in debug builds there may be even more data sent for debugging purposes.

    Framerate of the app does not matter, only the TickRate property in NetworkManager should affect how many packets are sent per second.

    How do you measure the kbp/s?

    For comparison:
    "As of 2021, most modern games use about 40 MB to 140 MB of internet data per hour."
     
    Last edited: Feb 27, 2023
  3. simon-lemay-unity

    simon-lemay-unity

    Unity Technologies

    Joined:
    Jul 19, 2021
    Posts:
    427
    I'd suggest installing the multiplayer tools package and looking at the network profiler.

    You also mention protocol headers and such not being large, but when compared to 22 bytes of data, they will be significant. If you're using Unity Relay, the headers alone will be larger than your data. And depending on how you're measuring your bandwidth, it may also be including UDP or IP headers too (or even the Ethernet framing). Those would add up too.
     
  4. guram58chaganava

    guram58chaganava

    Joined:
    Jul 8, 2020
    Posts:
    5
    Thank you for the response!

    I have built and run the app on Android where I checked data usage. The resulting value was divided by the time the app was working. So I have got data usage in a unit of time.
     
  5. guram58chaganava

    guram58chaganava

    Joined:
    Jul 8, 2020
    Posts:
    5
    Generally, the bandwidth consumption I have measured is not too high for multiplayer games while using Ethernet or Wi-Fi. However, I am not making a game. My project aims to create a 3D app designed to work on Wi-Fi as well as mobile data. Therefore, it is important to use as little data as possible.
     
  6. guram58chaganava

    guram58chaganava

    Joined:
    Jul 8, 2020
    Posts:
    5
    As I guessed from the comments, the bandwidth consumption which I measured is about normal for the Unity Relay service. So, what are other ways of data synchronization besides Relay service? Are there alternative tools that are expected to use less data?