Networking stubs, for the network games in this repo.

MonoGame.Xna.Framework.Net/GamerServices/GamerPrivileges.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Microsoft.Xna.Framework.GamerServices
+{
+	public class GamerPrivileges
+	{
+		public bool AllowOnlineSessions { get; set; }
+	}
+}

MonoGame.Xna.Framework.Net/GamerServices/GamerServices.cs

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+using System;
+using System.Collections.Generic;
+using Microsoft.Xna.Framework;
+
+namespace Microsoft.Xna.Framework.GamerServices
+{
+    /// <summary>
+    /// Defines gamer presence modes.
+    /// </summary>
+    public enum GamerPresenceMode
+    {
+        /// <summary>
+        /// Not online.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Online and available.
+        /// </summary>
+        Online,
+
+        /// <summary>
+        /// Away from keyboard.
+        /// </summary>
+        Away,
+
+        /// <summary>
+        /// Busy playing a game.
+        /// </summary>
+        Busy,
+
+        /// <summary>
+        /// Playing a specific game.
+        /// </summary>
+        PlayingGame,
+
+        /// <summary>
+        /// At the main menu.
+        /// </summary>
+        AtMenu,
+
+        /// <summary>
+        /// Waiting for other players.
+        /// </summary>
+        WaitingForPlayers,
+
+        /// <summary>
+        /// Waiting in lobby.
+        /// </summary>
+        WaitingInLobby,
+
+        /// <summary>
+        /// Currently winning.
+        /// </summary>
+        Winning,
+
+        /// <summary>
+        /// Currently losing.
+        /// </summary>
+        Losing,
+
+        /// <summary>
+        /// Score is tied.
+        /// </summary>
+        ScoreIsTied
+    }
+
+    /// <summary>
+    /// Gamer presence information.
+    /// </summary>
+    public class GamerPresence
+    {
+        /// <summary>
+        /// Gets or sets the presence mode.
+        /// </summary>
+        public GamerPresenceMode PresenceMode { get; set; } = GamerPresenceMode.Online;
+
+        /// <summary>
+        /// Gets or sets the presence value.
+        /// </summary>
+        public int PresenceValue { get; set; }
+    }
+
+    /// <summary>
+    /// Represents a signed-in gamer.
+    /// </summary>
+    public class SignedInGamer : Gamer
+    {
+        private static SignedInGamer current;
+
+        /// <summary>
+        /// Gets the current signed-in gamer.
+        /// </summary>
+        public static SignedInGamer Current
+        {
+            get
+            {
+                if (current == null)
+                {
+                    current = new SignedInGamer();
+                    current.SetGamertag(Environment.UserName);
+                }
+                return current;
+            }
+            internal set => current = value;
+        }
+
+        private string gamertag;
+
+        /// <summary>
+        /// Gets or sets the gamertag for this gamer.
+        /// </summary>
+        public override string Gamertag 
+        { 
+            get => gamertag;
+        }
+
+        /// <summary>
+        /// Sets the gamertag for this gamer.
+        /// </summary>
+        internal void SetGamertag(string value)
+        {
+            gamertag = value;
+        }
+
+        /// <summary>
+        /// Gets whether this gamer is signed in to a live service.
+        /// </summary>
+        public bool IsSignedInToLive => false; // Mock implementation
+
+        /// <summary>
+        /// Gets whether this gamer is a guest.
+        /// </summary>
+        public bool IsGuest => false;
+
+        /// <summary>
+        /// Gets the display name for this gamer.
+        /// </summary>
+        public new string DisplayName => Gamertag;
+
+        /// <summary>
+        /// Gets the presence information for this gamer.
+        /// </summary>
+        public GamerPresence Presence { get; } = new GamerPresence();
+
+        /// <summary>
+        /// Gets the player index for this gamer.
+        /// </summary>
+        public PlayerIndex PlayerIndex { get; internal set; } = PlayerIndex.One;
+
+        internal SignedInGamer() { }
+
+		public GamerPrivileges Privileges
+		{
+			get;
+			private set;
+		}
+	}
+
+    /// <summary>
+    /// Provides access to platform services.
+    /// </summary>
+    public static class Guide
+    {
+        /// <summary>
+        /// Gets whether the current game is running in trial mode.
+        /// </summary>
+        public static bool IsTrialMode => false; // Mock implementation - not in trial mode
+
+        /// <summary>
+        /// Gets whether the Guide is visible.
+        /// </summary>
+        public static bool IsVisible => false; // Mock implementation
+
+        /// <summary>
+        /// Gets whether screen saver is enabled.
+        /// </summary>
+        public static bool IsScreenSaverEnabled
+        {
+            get => false;
+            set { /* Mock implementation */ }
+        }
+
+        /// <summary>
+        /// Shows a message box to the user.
+        /// </summary>
+        public static IAsyncResult BeginShowMessageBox(
+            string title,
+            string text,
+            IEnumerable<string> buttons,
+            int focusButton,
+            MessageBoxIcon icon,
+            AsyncCallback callback,
+            object state)
+        {
+            // Mock implementation - for now just return a completed result
+            var result = new MockAsyncResult(state, true);
+            callback?.Invoke(result);
+            return result;
+        }
+
+        /// <summary>
+        /// Ends the message box operation.
+        /// </summary>
+        public static int? EndShowMessageBox(IAsyncResult result)
+        {
+            return 0; // Mock implementation - first button selected
+        }
+
+        /// <summary>
+        /// Shows the sign-in interface.
+        /// </summary>
+        public static IAsyncResult BeginShowSignIn(int paneCount, bool onlineOnly, AsyncCallback callback, object state)
+        {
+            var result = new MockAsyncResult(state, true);
+            callback?.Invoke(result);
+            return result;
+        }
+
+        /// <summary>
+        /// Ends the sign-in operation.
+        /// </summary>
+        public static void EndShowSignIn(IAsyncResult result)
+        {
+            // Mock implementation
+        }
+
+        /// <summary>
+        /// Shows the sign-in interface (synchronous version).
+        /// </summary>
+        public static void ShowSignIn(int paneCount, bool onlineOnly)
+        {
+            // Mock implementation
+        }
+
+        /// <summary>
+        /// Shows the marketplace.
+        /// </summary>
+        public static void ShowMarketplace(int playerIndex)
+        {
+            // Mock implementation
+        }
+    }
+
+    /// <summary>
+    /// Message box icon types.
+    /// </summary>
+    public enum MessageBoxIcon
+    {
+        None,
+        Error,
+        Warning,
+        Alert
+    }
+
+    /// <summary>
+    /// Mock implementation of IAsyncResult for testing.
+    /// </summary>
+    internal class MockAsyncResult : IAsyncResult
+    {
+        public MockAsyncResult(object asyncState, bool isCompleted)
+        {
+            AsyncState = asyncState;
+            IsCompleted = isCompleted;
+            CompletedSynchronously = isCompleted;
+        }
+
+        public object AsyncState { get; }
+        public WaitHandle AsyncWaitHandle => new ManualResetEvent(IsCompleted);
+        public bool CompletedSynchronously { get; }
+        public bool IsCompleted { get; }
+    }
+
+    /// <summary>
+    /// Game component that provides gamer services functionality.
+    /// </summary>
+    public class GamerServicesComponent : IGameComponent
+    {
+        /// <summary>
+        /// Initializes a new GamerServicesComponent.
+        /// </summary>
+        /// <param name="game">The game instance.</param>
+        public GamerServicesComponent(Game game)
+        {
+            // Mock implementation
+        }
+
+        /// <summary>
+        /// Updates the gamer services.
+        /// </summary>
+        /// <param name="gameTime">Game timing information.</param>
+        public void Update(GameTime gameTime)
+        {
+            // Mock implementation - gamer services update logic would go here
+        }
+
+        /// <summary>
+        /// Initializes the component.
+        /// </summary>
+        public void Initialize()
+        {
+            // Mock implementation
+        }
+    }
+
+    /// <summary>
+    /// Base class for all gamer types.
+    /// </summary>
+    public abstract class Gamer
+    {
+        /// <summary>
+        /// Gets the gamertag for this gamer.
+        /// </summary>
+        public abstract string Gamertag { get; }
+
+        /// <summary>
+        /// Gets the display name for this gamer.
+        /// </summary>
+        public virtual string DisplayName => Gamertag;
+
+        /// <summary>
+        /// Gets custom data associated with this gamer.
+        /// </summary>
+        public object Tag { get; set; }
+
+        /// <summary>
+        /// Gets the signed-in gamers.
+        /// </summary>
+        public static GamerCollection<SignedInGamer> SignedInGamers => signedInGamers;
+
+        private static readonly GamerCollection<SignedInGamer> signedInGamers;
+
+        static Gamer()
+        {
+            // Initialize with current signed-in gamer
+            var gamers = new List<SignedInGamer> { SignedInGamer.Current };
+            signedInGamers = new GamerCollection<SignedInGamer>(gamers);
+        }
+    }
+
+    /// <summary>
+    /// Collection of gamers.
+    /// </summary>
+    public class GamerCollection<T> : System.Collections.ObjectModel.ReadOnlyCollection<T>
+    {
+        public GamerCollection(IList<T> list) : base(list) { }
+    }
+}

MonoGame.Xna.Framework.Net/GamerServices/NetworkNotAvailableException.cs

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+using Microsoft.Xna.Framework.Net;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Microsoft.Xna.Framework.GamerServices
+{
+	public class NetworkNotAvailableException : NetworkException
+	{
+	}
+}

MonoGame.Xna.Framework.Net/MonoGame.Xna.Framework.Net.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>disable</Nullable>
+    <RootNamespace>Microsoft.Xna.Framework</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="MonoGame.Framework.DesktopGL" Version="3.8.*" />
+    <PackageReference Include="System.Text.Json" Version="8.0.*" />
+  </ItemGroup>
+
+</Project>

MonoGame.Xna.Framework.Net/Net/AvailableNetworkSession.cs

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+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Threading.Tasks;
+
+namespace Microsoft.Xna.Framework.Net
+{
+    /// <summary>
+    /// Represents an available network session that can be joined.
+    /// </summary>
+    public class AvailableNetworkSession
+    {
+        internal AvailableNetworkSession(
+            string sessionName,
+            string hostGamertag,
+            int currentGamerCount,
+            int openPublicGamerSlots,
+            int openPrivateGamerSlots,
+            NetworkSessionType sessionType,
+            IDictionary<string, object> sessionProperties)
+        {
+            SessionName = sessionName;
+            HostGamertag = hostGamertag;
+            CurrentGamerCount = currentGamerCount;
+            OpenPublicGamerSlots = openPublicGamerSlots;
+            OpenPrivateGamerSlots = openPrivateGamerSlots;
+            SessionType = sessionType;
+            SessionProperties = new Dictionary<string, object>(sessionProperties);
+        }
+
+        /// <summary>
+        /// Gets the name of the session.
+        /// </summary>
+        public string SessionName { get; }
+
+        /// <summary>
+        /// Gets the gamertag of the host.
+        /// </summary>
+        public string HostGamertag { get; }
+
+        /// <summary>
+        /// Gets the current number of gamers in the session.
+        /// </summary>
+        public int CurrentGamerCount { get; }
+
+        /// <summary>
+        /// Gets the number of open public gamer slots.
+        /// </summary>
+        public int OpenPublicGamerSlots { get; }
+
+        /// <summary>
+        /// Gets the number of open private gamer slots.
+        /// </summary>
+        public int OpenPrivateGamerSlots { get; }
+
+        /// <summary>
+        /// Gets the type of the session.
+        /// </summary>
+        public NetworkSessionType SessionType { get; }
+
+        /// <summary>
+        /// Gets the session properties.
+        /// </summary>
+        public IDictionary<string, object> SessionProperties { get; }
+
+        /// <summary>
+        /// Gets the quality of service information.
+        /// </summary>
+        public QualityOfService QualityOfService { get; internal set; } = new QualityOfService();
+    }
+
+    /// <summary>
+    /// Collection of available network sessions.
+    /// </summary>
+    public class AvailableNetworkSessionCollection : ReadOnlyCollection<AvailableNetworkSession>, IDisposable
+    {
+        private bool disposed = false;
+
+        internal AvailableNetworkSessionCollection() : base(new List<AvailableNetworkSession>()) { }
+        
+        internal AvailableNetworkSessionCollection(IList<AvailableNetworkSession> sessions) : base(sessions) { }
+
+        /// <summary>
+        /// Disposes of the collection resources.
+        /// </summary>
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        /// <summary>
+        /// Disposes of the collection resources.
+        /// </summary>
+        /// <param name="disposing">True if disposing managed resources.</param>
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!disposed)
+            {
+                if (disposing)
+                {
+                    // Clean up managed resources if needed
+                    // The ReadOnlyCollection doesn't need special cleanup
+                }
+                disposed = true;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Properties used when creating or searching for network sessions.
+    /// </summary>
+    public class NetworkSessionProperties : Dictionary<string, object>
+    {
+        /// <summary>
+        /// Initializes a new NetworkSessionProperties.
+        /// </summary>
+        public NetworkSessionProperties() : base() { }
+
+        /// <summary>
+        /// Initializes a new NetworkSessionProperties with a specified capacity.
+        /// </summary>
+        public NetworkSessionProperties(int capacity) : base(capacity) { }
+    }
+
+    /// <summary>
+    /// Quality of service information for a network session.
+    /// </summary>
+    public class QualityOfService
+    {
+        /// <summary>
+        /// Gets the average round trip time in milliseconds.
+        /// </summary>
+        public TimeSpan AverageRoundTripTime { get; internal set; } = TimeSpan.FromMilliseconds(50);
+
+        /// <summary>
+        /// Gets the minimum round trip time in milliseconds.
+        /// </summary>
+        public TimeSpan MinimumRoundTripTime { get; internal set; } = TimeSpan.FromMilliseconds(20);
+
+        /// <summary>
+        /// Gets the maximum round trip time in milliseconds.
+        /// </summary>
+        public TimeSpan MaximumRoundTripTime { get; internal set; } = TimeSpan.FromMilliseconds(100);
+
+        /// <summary>
+        /// Gets the bytes per second being sent.
+        /// </summary>
+        public int BytesPerSecondSent { get; internal set; } = 0;
+
+        /// <summary>
+        /// Gets the bytes per second being received.
+        /// </summary>
+        public int BytesPerSecondReceived { get; internal set; } = 0;
+
+        /// <summary>
+        /// Gets whether the connection is available.
+        /// </summary>
+        public bool IsAvailable { get; internal set; } = true;
+    }
+
+    /// <summary>
+    /// Wrapper for async operations to provide XNA-compatible IAsyncResult interface.
+    /// </summary>
+    internal class AsyncResultWrapper<T> : IAsyncResult
+    {
+        private readonly Task<T> task;
+        private readonly object asyncState;
+
+        public AsyncResultWrapper(Task<T> task, AsyncCallback callback, object asyncState)
+        {
+            this.task = task;
+            this.asyncState = asyncState;
+
+            if (callback != null)
+            {
+                task.ContinueWith(t => callback(this));
+            }
+        }
+
+        public object AsyncState => asyncState;
+
+        public System.Threading.WaitHandle AsyncWaitHandle => ((IAsyncResult)task).AsyncWaitHandle;
+
+        public bool CompletedSynchronously => task.IsCompletedSuccessfully;
+
+        public bool IsCompleted => task.IsCompleted;
+
+        public T GetResult()
+        {
+            return task.Result;
+        }
+    }
+}

MonoGame.Xna.Framework.Net/Net/Enums.cs

@@ -0,0 +1,184 @@
+using System;
+using Microsoft.Xna.Framework;
+
+namespace Microsoft.Xna.Framework.Net
+{
+    /// <summary>
+    /// Types of network sessions that can be created or joined.
+    /// </summary>
+    public enum NetworkSessionType
+    {
+        /// <summary>
+        /// Local session for single-machine multiplayer.
+        /// </summary>
+        Local,
+
+        /// <summary>
+        /// System link session for LAN multiplayer.
+        /// </summary>
+        SystemLink,
+
+        /// <summary>
+        /// Player match session for online multiplayer.
+        /// </summary>
+        PlayerMatch,
+
+        /// <summary>
+        /// Ranked session for competitive online multiplayer.
+        /// </summary>
+        Ranked
+    }
+
+    /// <summary>
+    /// Options for sending data over the network.
+    /// </summary>
+    public enum SendDataOptions
+    {
+        /// <summary>
+        /// No special options - unreliable delivery.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Reliable delivery - guarantees the data will arrive.
+        /// </summary>
+        Reliable,
+
+        /// <summary>
+        /// In-order delivery - data arrives in the order sent.
+        /// </summary>
+        InOrder,
+
+        /// <summary>
+        /// Reliable and in-order delivery.
+        /// </summary>
+        ReliableInOrder = Reliable | InOrder
+    }
+
+    /// <summary>
+    /// Current state of a network session.
+    /// </summary>
+    public enum NetworkSessionState
+    {
+        /// <summary>
+        /// Session is being created.
+        /// </summary>
+        Creating,
+
+        /// <summary>
+        /// Session is in the lobby, waiting for players.
+        /// </summary>
+        Lobby,
+
+        /// <summary>
+        /// Session is in an active game.
+        /// </summary>
+        Playing,
+
+        /// <summary>
+        /// Session has ended.
+        /// </summary>
+        Ended
+    }
+
+    /// <summary>
+    /// Defines the different types of gamers in a networked session.
+    /// </summary>
+    public enum GamerType
+    {
+        /// <summary>
+        /// A local gamer.
+        /// </summary>
+        Local,
+
+        /// <summary>
+        /// A remote gamer.
+        /// </summary>
+        Remote
+    }
+}
+
+namespace Microsoft.Xna.Framework.Net
+{
+    /// <summary>
+    /// Exception thrown when network operations fail.
+    /// </summary>
+    public class NetworkException : Exception
+    {
+        public NetworkException() : base() { }
+        public NetworkException(string message) : base(message) { }
+        public NetworkException(string message, Exception innerException) : base(message, innerException) { }
+    }
+
+    /// <summary>
+    /// Exception thrown when gamer privilege operations fail.
+    /// </summary>
+    public class GamerPrivilegeException : Exception
+    {
+        public GamerPrivilegeException() : base() { }
+        public GamerPrivilegeException(string message) : base(message) { }
+        public GamerPrivilegeException(string message, Exception innerException) : base(message, innerException) { }
+    }
+
+    /// <summary>
+    /// Exception thrown when network session join operations fail.
+    /// </summary>
+    public class NetworkSessionJoinException : Exception
+    {
+        /// <summary>
+        /// Gets the join error type.
+        /// </summary>
+        public NetworkSessionJoinError JoinError { get; }
+
+        public NetworkSessionJoinException() : base() 
+        {
+            JoinError = NetworkSessionJoinError.Unknown;
+        }
+
+        public NetworkSessionJoinException(string message) : base(message) 
+        {
+            JoinError = NetworkSessionJoinError.Unknown;
+        }
+
+        public NetworkSessionJoinException(string message, Exception innerException) : base(message, innerException) 
+        {
+            JoinError = NetworkSessionJoinError.Unknown;
+        }
+
+        public NetworkSessionJoinException(NetworkSessionJoinError joinError) : base() 
+        {
+            JoinError = joinError;
+        }
+
+        public NetworkSessionJoinException(string message, NetworkSessionJoinError joinError) : base(message) 
+        {
+            JoinError = joinError;
+        }
+    }
+
+    /// <summary>
+    /// Types of network session join errors.
+    /// </summary>
+    public enum NetworkSessionJoinError
+    {
+        /// <summary>
+        /// Unknown error.
+        /// </summary>
+        Unknown,
+
+        /// <summary>
+        /// Session is full.
+        /// </summary>
+        SessionFull,
+
+        /// <summary>
+        /// Session not found.
+        /// </summary>
+        SessionNotFound,
+
+        /// <summary>
+        /// Session not joinable.
+        /// </summary>
+        SessionNotJoinable
+    }
+}

MonoGame.Xna.Framework.Net/Net/EventArgs.cs

@@ -0,0 +1,122 @@
+using Microsoft.Xna.Framework.GamerServices;
+using System;
+
+namespace Microsoft.Xna.Framework.Net
+{
+    /// <summary>
+    /// Event arguments for when an invite is accepted.
+    /// </summary>
+    public class InviteAcceptedEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Gets the gamer who accepted the invite.
+        /// </summary>
+        public SignedInGamer Gamer { get; internal set; }
+
+        /// <summary>
+        /// Gets whether the operation completed successfully.
+        /// </summary>
+        public bool IsSignedInGamer { get; internal set; }
+
+        internal InviteAcceptedEventArgs(SignedInGamer gamer, bool isSignedInGamer)
+        {
+            Gamer = gamer;
+            IsSignedInGamer = isSignedInGamer;
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for when a game ends.
+    /// </summary>
+    public class GameEndedEventArgs : EventArgs
+    {
+        internal GameEndedEventArgs() { }
+    }
+
+    /// <summary>
+    /// Event arguments for when a network session ends.
+    /// </summary>
+    public class NetworkSessionEndedEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Gets the reason the session ended.
+        /// </summary>
+        public NetworkSessionEndReason EndReason { get; internal set; }
+
+        internal NetworkSessionEndedEventArgs(NetworkSessionEndReason endReason)
+        {
+            EndReason = endReason;
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for when a gamer leaves the session.
+    /// </summary>
+    public class GamerLeftEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Gets the gamer who left.
+        /// </summary>
+        public NetworkGamer Gamer { get; internal set; }
+
+        internal GamerLeftEventArgs(NetworkGamer gamer)
+        {
+            Gamer = gamer;
+        }
+    }
+
+    /// <summary>
+    /// Event arguments for when a game starts.
+    /// </summary>
+    public class GameStartedEventArgs : EventArgs
+    {
+        internal GameStartedEventArgs() { }
+    }
+
+    /// <summary>
+    /// Event arguments for when a gamer joins the session.
+    /// </summary>
+    public class GamerJoinedEventArgs : EventArgs
+    {
+        /// <summary>
+        /// Gets the gamer who joined.
+        /// </summary>
+        public NetworkGamer Gamer { get; internal set; }
+
+        internal GamerJoinedEventArgs(NetworkGamer gamer)
+        {
+            Gamer = gamer;
+        }
+    }
+
+    /// <summary>
+    /// Reasons why a network session ended.
+    /// </summary>
+    public enum NetworkSessionEndReason
+    {
+        /// <summary>
+        /// The session ended normally.
+        /// </summary>
+        ClientSignedOut,
+
+        /// <summary>
+        /// The host ended the session.
+        /// </summary>
+        HostEndedSession,
+
+		/// <summary>
+		/// The host removed the user.
+		/// </summary>
+		RemovedByHost,
+
+		/// <summary>
+		/// The session was disconnected.
+		/// </summary>
+		Disconnected,
+
+        /// <summary>
+        /// A network error occurred.
+        /// </summary>
+        NetworkError
+    }
+}

MonoGame.Xna.Framework.Net/Net/NetworkGamer.cs

@@ -0,0 +1,366 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using Microsoft.Xna.Framework.GamerServices;
+
+namespace Microsoft.Xna.Framework.Net
+{
+    /// <summary>
+    /// Represents a player in a network session.
+    /// </summary>
+    public class NetworkGamer
+    {
+        private static NetworkGamer localGamer;
+        private readonly NetworkSession session;
+        private readonly string id;
+        private readonly bool isLocal;
+        private readonly bool isHost;
+        private string gamertag;
+        private bool isReady;
+        private object tag;
+
+        // Network performance properties
+        private TimeSpan roundtripTime = TimeSpan.Zero;
+
+        internal NetworkGamer(NetworkSession session, string id, bool isLocal, bool isHost, string gamertag)
+        {
+            this.session = session;
+            this.id = id;
+            this.isLocal = isLocal;
+            this.isHost = isHost;
+            this.gamertag = gamertag;
+        }
+
+        /// <summary>
+        /// Gets the unique identifier for this gamer.
+        /// </summary>
+        public string Id => id;
+
+        /// <summary>
+        /// Gets whether this gamer is the local player.
+        /// </summary>
+        public bool IsLocal => isLocal;
+
+        /// <summary>
+        /// Gets whether this gamer is the host of the session.
+        /// </summary>
+        public bool IsHost => isHost;
+
+        /// <summary>
+        /// Gets or sets the gamertag for this gamer.
+        /// </summary>
+        public string Gamertag
+        {
+            get => gamertag;
+            set => gamertag = value ?? throw new ArgumentNullException(nameof(value));
+        }
+
+        /// <summary>
+        /// Gets or sets whether this gamer is ready to start the game.
+        /// </summary>
+        public bool IsReady
+        {
+            get => isReady;
+            set
+            {
+                if (isReady != value)
+                {
+                    isReady = value;
+                    // Notify session of readiness change if this is the local gamer
+                    if (isLocal)
+                    {
+                        session?.NotifyReadinessChanged(this);
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets custom data associated with this gamer.
+        /// </summary>
+        public object Tag
+        {
+            get => tag;
+            set => tag = value;
+        }
+
+        /// <summary>
+        /// Gets the machine for this network gamer.
+        /// </summary>
+        public NetworkMachine Machine => null; // Mock implementation
+
+        /// <summary>
+        /// Gets whether data is available to be received from this gamer.
+        /// </summary>
+        public bool IsDataAvailable => false; // Mock implementation
+
+        /// <summary>
+        /// Gets the SignedInGamer associated with this NetworkGamer.
+        /// </summary>
+        public GamerServices.SignedInGamer SignedInGamer => GamerServices.SignedInGamer.Current;
+
+        /// <summary>
+        /// Gets whether this gamer is muted by the local user.
+        /// </summary>
+        public bool IsMutedByLocalUser => false; // Mock implementation
+
+        /// <summary>
+        /// Gets whether this gamer is currently talking.
+        /// </summary>
+        public bool IsTalking => false; // Mock implementation
+
+        /// <summary>
+        /// Gets whether this gamer has voice capabilities.
+        /// </summary>
+        public bool HasVoice => false; // Mock implementation
+
+        /// <summary>
+        /// Receives data from this gamer.
+        /// </summary>
+        /// <param name="data">Array to receive the data into.</param>
+        /// <param name="sender">The gamer who sent the data.</param>
+        /// <returns>The number of bytes received.</returns>
+        public int ReceiveData(byte[] data, out NetworkGamer sender)
+        {
+            sender = null;
+            return 0; // Mock implementation
+        }
+
+        /// <summary>
+        /// Receives data from this gamer using PacketReader.
+        /// </summary>
+        /// <param name="data">Array to receive the data into.</param>
+        /// <param name="sender">The gamer who sent the data.</param>
+        /// <returns>The number of bytes received.</returns>
+        public int ReceiveData(PacketReader data, out NetworkGamer sender)
+        {
+            sender = null;
+            return 0; // Mock implementation
+        }
+
+        /// <summary>
+        /// Sends data to other gamers in the session.
+        /// </summary>
+        /// <param name="data">The data to send.</param>
+        /// <param name="options">Send options.</param>
+        public void SendData(byte[] data, SendDataOptions options)
+        {
+            // Mock implementation
+        }
+
+        /// <summary>
+        /// Sends data to specific gamers in the session.
+        /// </summary>
+        /// <param name="data">The data to send.</param>
+        /// <param name="options">Send options.</param>
+        /// <param name="recipients">The gamers to send to.</param>
+        public void SendData(byte[] data, SendDataOptions options, IEnumerable<NetworkGamer> recipients)
+        {
+            // Mock implementation
+        }
+
+        /// <summary>
+        /// Sends data using PacketWriter.
+        /// </summary>
+        /// <param name="data">The data to send.</param>
+        /// <param name="options">Send options.</param>
+        public void SendData(PacketWriter data, SendDataOptions options)
+        {
+            // Mock implementation
+        }
+
+        /// <summary>
+        /// Sends data using PacketWriter to specific recipients.
+        /// </summary>
+        /// <param name="data">The data to send.</param>
+        /// <param name="options">Send options.</param>
+        /// <param name="recipients">The gamers to send to.</param>
+        public void SendData(PacketWriter data, SendDataOptions options, IEnumerable<NetworkGamer> recipients)
+        {
+            // Mock implementation
+        }
+
+        /// <summary>
+        /// Sends data using PacketWriter to a specific recipient.
+        /// </summary>
+        /// <param name="data">The data to send.</param>
+        /// <param name="options">Send options.</param>
+        /// <param name="recipient">The gamer to send to.</param>
+        public void SendData(PacketWriter data, SendDataOptions options, NetworkGamer recipient)
+        {
+            // Mock implementation - convert single gamer to enumerable
+            SendData(data, options, new[] { recipient });
+        }
+
+        /// <summary>
+        /// Sends byte array data to a specific recipient.
+        /// </summary>
+        /// <param name="data">The data to send.</param>
+        /// <param name="options">Send options.</param>
+        /// <param name="recipient">The gamer to send to.</param>
+        public void SendData(byte[] data, SendDataOptions options, NetworkGamer recipient)
+        {
+            // Mock implementation - convert single gamer to enumerable
+            SendData(data, options, new[] { recipient });
+        }
+
+        /// <summary>
+        /// Gets the current round-trip time for network communication with this gamer.
+        /// </summary>
+        public TimeSpan RoundtripTime => roundtripTime;
+
+        /// <summary>
+        /// Updates the round-trip time (internal use).
+        /// </summary>
+        internal void UpdateRoundtripTime(TimeSpan newRoundtripTime)
+        {
+            roundtripTime = newRoundtripTime;
+        }
+
+        public override string ToString()
+        {
+            return $"{Gamertag} ({(IsLocal ? "Local" : "Remote")}, {(IsHost ? "Host" : "Player")})";
+        }
+
+        public override bool Equals(object obj)
+        {
+            return obj is NetworkGamer other && Id == other.Id;
+        }
+
+        public override int GetHashCode()
+        {
+            return Id.GetHashCode();
+        }
+
+        /// <summary>
+        /// Gets the local gamer.
+        /// </summary>
+        public static NetworkGamer LocalGamer 
+        { 
+            get => localGamer; 
+            internal set => localGamer = value; 
+        }
+
+        /// <summary>
+        /// Implicit conversion from NetworkGamer to SignedInGamer.
+        /// </summary>
+        public static implicit operator SignedInGamer(NetworkGamer gamer)
+        {
+            return gamer?.SignedInGamer;
+        }
+    }
+
+    /// <summary>
+    /// Collection of network gamers in a session.
+    /// </summary>
+    public class GamerCollection : ReadOnlyCollection<NetworkGamer>
+    {
+        internal GamerCollection(IList<NetworkGamer> list) : base(list) { }
+
+        /// <summary>
+        /// Finds a gamer by their gamertag.
+        /// </summary>
+        /// <param name="gamertag">The gamertag to search for.</param>
+        /// <returns>The gamer with the specified gamertag, or null if not found.</returns>
+        public NetworkGamer FindGamerById(string id)
+        {
+            foreach (var gamer in this)
+            {
+                if (gamer.Id == id)
+                    return gamer;
+            }
+            return null;
+        }
+
+        /// <summary>
+        /// Gets the host gamer of the session.
+        /// </summary>
+        public NetworkGamer Host
+        {
+            get
+            {
+                foreach (var gamer in this)
+                {
+                    if (gamer.IsHost)
+                        return gamer;
+                }
+                return null;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Represents a machine in a network session.
+    /// </summary>
+    public class NetworkMachine
+    {
+        /// <summary>
+        /// Gets the gamers on this machine.
+        /// </summary>
+        public GamerCollection Gamers { get; } = new GamerCollection(new List<NetworkGamer>());
+    }
+
+    /// <summary>
+    /// Collection of local network gamers in a session.
+    /// </summary>
+    public class LocalGamerCollection : ReadOnlyCollection<LocalNetworkGamer>
+    {
+        internal LocalGamerCollection(IList<LocalNetworkGamer> list) : base(list) { }
+
+        /// <summary>
+        /// Finds a local gamer by their ID.
+        /// </summary>
+        /// <param name="id">The ID to search for.</param>
+        /// <returns>The local gamer with the specified ID, or null if not found.</returns>
+        public LocalNetworkGamer FindGamerById(string id)
+        {
+            foreach (var gamer in this)
+            {
+                if (gamer.Id == id)
+                    return gamer;
+            }
+            return null;
+        }
+
+        /// <summary>
+        /// Gets the host gamer of the session (if local).
+        /// </summary>
+        public LocalNetworkGamer Host
+        {
+            get
+            {
+                foreach (var gamer in this)
+                {
+                    if (gamer.IsHost)
+                        return gamer;
+                }
+                return null;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Represents a local network gamer.
+    /// </summary>
+    public class LocalNetworkGamer : NetworkGamer
+    {
+        internal LocalNetworkGamer(NetworkSession session, string id, bool isHost, string gamertag)
+            : base(session, id, true, isHost, gamertag)
+        {
+        }
+
+        /// <summary>
+        /// Gets whether this local gamer is sending data.
+        /// </summary>
+        public bool IsSendingData => false; // Mock implementation
+
+        /// <summary>
+        /// Enables or disables sending data for this local gamer.
+        /// </summary>
+        /// <param name="options">Send data options.</param>
+        public void EnableSendData(SendDataOptions options)
+        {
+            // Mock implementation
+        }
+    }
+}

MonoGame.Xna.Framework.Net/Net/NetworkSession.cs

@@ -0,0 +1,636 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Xna.Framework.GamerServices;
+
+namespace Microsoft.Xna.Framework.Net
+{
+    /// <summary>
+    /// Represents a network session for multiplayer gaming.
+    /// </summary>
+    public class NetworkSession : IDisposable
+    {
+        private readonly List<NetworkGamer> gamers;
+        private readonly GamerCollection gamerCollection;
+        private readonly NetworkSessionType sessionType;
+        private readonly int maxGamers;
+        private readonly int privateGamerSlots;
+        private readonly UdpClient udpClient;
+        private readonly Dictionary<string, IPEndPoint> gamerEndpoints;
+        private readonly object lockObject = new object();
+        
+        private NetworkSessionState sessionState;
+        private bool disposed;
+        private bool isHost;
+        private string sessionId;
+        private Task receiveTask;
+        private CancellationTokenSource cancellationTokenSource;
+
+        // Events
+        public event EventHandler<GameStartedEventArgs> GameStarted;
+        public event EventHandler<GameEndedEventArgs> GameEnded;
+        public event EventHandler<GamerJoinedEventArgs> GamerJoined;
+        public event EventHandler<GamerLeftEventArgs> GamerLeft;
+        public event EventHandler<NetworkSessionEndedEventArgs> SessionEnded;
+
+        // Static event for invite acceptance
+        public static event EventHandler<InviteAcceptedEventArgs> InviteAccepted;
+
+        /// <summary>
+        /// Initializes a new NetworkSession.
+        /// </summary>
+        private NetworkSession(NetworkSessionType sessionType, int maxGamers, int privateGamerSlots, bool isHost)
+        {
+            this.sessionType = sessionType;
+            this.maxGamers = maxGamers;
+            this.privateGamerSlots = privateGamerSlots;
+            this.isHost = isHost;
+            this.sessionId = Guid.NewGuid().ToString();
+            this.sessionState = NetworkSessionState.Creating;
+            
+            gamers = new List<NetworkGamer>();
+            gamerCollection = new GamerCollection(gamers);
+            gamerEndpoints = new Dictionary<string, IPEndPoint>();
+            
+            // Initialize UDP client for networking
+            udpClient = new UdpClient();
+            cancellationTokenSource = new CancellationTokenSource();
+            
+            // Add local gamer
+            var localGamer = new LocalNetworkGamer(this, Guid.NewGuid().ToString(), isHost, SignedInGamer.Current?.Gamertag ?? "Player");
+            NetworkGamer.LocalGamer = localGamer;
+            AddGamer(localGamer);
+        }
+
+        /// <summary>
+        /// Gets all gamers in the session.
+        /// </summary>
+        public GamerCollection AllGamers => gamerCollection;
+
+        /// <summary>
+        /// Gets local gamers in the session.
+        /// </summary>
+        public LocalGamerCollection LocalGamers
+        {
+            get
+            {
+                var localGamers = gamers.Where(g => g.IsLocal).OfType<LocalNetworkGamer>().ToList();
+                return new LocalGamerCollection(localGamers);
+            }
+        }
+
+        /// <summary>
+        /// Gets remote gamers in the session.
+        /// </summary>
+        public GamerCollection RemoteGamers
+        {
+            get
+            {
+                var remoteGamers = gamers.Where(g => !g.IsLocal).ToList();
+                return new GamerCollection(remoteGamers);
+            }
+        }
+
+        /// <summary>
+        /// Gets the host gamer.
+        /// </summary>
+        public NetworkGamer Host => AllGamers.Host;
+
+        /// <summary>
+        /// Gets whether this machine is the host.
+        /// </summary>
+        public bool IsHost => isHost;
+
+        /// <summary>
+        /// Gets whether everyone is ready to start the game.
+        /// </summary>
+        public bool IsEveryoneReady => AllGamers.All(g => g.IsReady);
+
+        /// <summary>
+        /// Gets the maximum number of gamers.
+        /// </summary>
+        public int MaxGamers => maxGamers;
+
+        /// <summary>
+        /// Gets the number of private gamer slots.
+        /// </summary>
+        public int PrivateGamerSlots => privateGamerSlots;
+
+        /// <summary>
+        /// Gets the session type.
+        /// </summary>
+        public NetworkSessionType SessionType => sessionType;
+
+        /// <summary>
+        /// Gets the current session state.
+        /// </summary>
+        public NetworkSessionState SessionState => sessionState;
+
+        /// <summary>
+        /// Gets the bytes per second being sent.
+        /// </summary>
+        public int BytesPerSecondSent => 0; // Mock implementation
+
+        /// <summary>
+        /// Gets the bytes per second being received.
+        /// </summary>
+        public int BytesPerSecondReceived => 0; // Mock implementation
+
+        /// <summary>
+        /// Gets whether the session allows host migration.
+        /// </summary>
+        public bool AllowHostMigration { get; set; } = true;
+
+        /// <summary>
+        /// Gets whether the session allows gamers to join during gameplay.
+        /// </summary>
+        public bool AllowJoinInProgress { get; set; } = true;
+
+        /// <summary>
+        /// Gets or sets custom session properties.
+        /// </summary>
+        public IDictionary<string, object> SessionProperties { get; set; } = new Dictionary<string, object>();
+
+        // Simulation properties for testing network conditions
+        private TimeSpan simulatedLatency = TimeSpan.Zero;
+        private float simulatedPacketLoss = 0.0f;
+
+        /// <summary>
+        /// Gets or sets the simulated network latency for testing purposes.
+        /// </summary>
+        public TimeSpan SimulatedLatency 
+        { 
+            get => simulatedLatency; 
+            set => simulatedLatency = value; 
+        }
+
+        /// <summary>
+        /// Gets or sets the simulated packet loss percentage for testing purposes.
+        /// </summary>
+        public float SimulatedPacketLoss 
+        { 
+            get => simulatedPacketLoss; 
+            set => simulatedPacketLoss = Math.Max(0.0f, Math.Min(1.0f, value)); 
+        }
+
+        /// <summary>
+        /// Begins creating a new network session.
+        /// </summary>
+		public static IAsyncResult BeginCreate(
+            NetworkSessionType sessionType,
+            IEnumerable<SignedInGamer> localGamers,
+            int maxGamers,
+            int privateGamerSlots,
+            NetworkSessionProperties sessionProperties,
+            AsyncCallback callback,
+            object asyncState
+        )
+		{
+			if (maxGamers < 1 || maxGamers > 4)
+			{
+				throw new ArgumentOutOfRangeException(nameof(maxGamers));
+			}
+			if (privateGamerSlots < 0 || privateGamerSlots > maxGamers)
+			{
+                throw new ArgumentOutOfRangeException(nameof(privateGamerSlots));
+			}
+
+            throw new NotImplementedException("Async creation with callback is not implemented yet.");
+		}
+
+		public static IAsyncResult BeginCreate(
+            NetworkSessionType sessionType,
+            int maxLocalGamers,
+            int maxGamers,
+            AsyncCallback callback = null,
+            object asyncState = null
+        )
+		{
+            if (maxLocalGamers < 1 || maxLocalGamers > 4)
+            {
+                throw new ArgumentOutOfRangeException(nameof(maxLocalGamers));
+            }
+
+			throw new NotImplementedException("Async creation with callback is not implemented yet.");
+		}
+
+		public static IAsyncResult BeginCreate(
+            NetworkSessionType sessionType,
+            int maxLocalGamers,
+            int maxGamers,
+            int privateGamerSlots,
+            NetworkSessionProperties sessionProperties,
+            AsyncCallback callback = null,
+            object asyncState = null
+        )
+		{
+			if (maxLocalGamers < 1 || maxLocalGamers > 4)
+			{
+				throw new ArgumentOutOfRangeException(nameof(maxLocalGamers));
+			}
+
+			if (maxLocalGamers < 1 || maxLocalGamers > 4)
+			{
+				throw new ArgumentOutOfRangeException(nameof(maxLocalGamers));
+			}
+			if (privateGamerSlots < 0 || privateGamerSlots > maxGamers)
+			{
+				throw new ArgumentOutOfRangeException(nameof(privateGamerSlots));
+			}
+
+			var task = Task.Run(() =>
+			{
+				var session = new NetworkSession(sessionType, maxGamers, privateGamerSlots, true);
+				session.sessionState = NetworkSessionState.Lobby;
+				return session;
+			});
+
+			return new AsyncResultWrapper<NetworkSession>(task, null, null);
+		}
+
+		/// <summary>
+		/// Ends the create session operation.
+		/// </summary>
+		public static NetworkSession EndCreate(IAsyncResult asyncResult)
+        {
+            if (asyncResult is AsyncResultWrapper<NetworkSession> wrapper)
+            {
+                return wrapper.GetResult();
+            }
+            throw new ArgumentException("Invalid async result", nameof(asyncResult));
+        }
+
+        /// <summary>
+        /// Begins finding available network sessions.
+        /// </summary>
+        public static IAsyncResult BeginFind(
+            NetworkSessionType sessionType,
+            int maxLocalGamers,
+            NetworkSessionProperties searchProperties,
+            AsyncCallback callback,
+            object asyncState)
+        {
+            var task = Task.Run(() =>
+            {
+                // Mock implementation - return empty collection for now
+                // In a real implementation, this would search for available sessions
+                return new AvailableNetworkSessionCollection();
+            });
+
+            return new AsyncResultWrapper<AvailableNetworkSessionCollection>(task, callback, asyncState);
+        }
+
+		public static IAsyncResult BeginFind(
+            NetworkSessionType sessionType,
+            IEnumerable<SignedInGamer> localGamers,
+            NetworkSessionProperties searchProperties,
+            AsyncCallback callback = null,
+            object asyncState = null
+        )
+		{
+			var task = Task.Run(() =>
+			{
+				// Mock implementation - return empty collection for now
+				// In a real implementation, this would search for available sessions
+				return new AvailableNetworkSessionCollection();
+			});
+
+			return new AsyncResultWrapper<AvailableNetworkSessionCollection>(task, callback, asyncState);
+		}
+
+		/// <summary>
+		/// Ends the find sessions operation.
+		/// </summary>
+		public static AvailableNetworkSessionCollection EndFind(IAsyncResult asyncResult)
+        {
+            if (asyncResult is AsyncResultWrapper<AvailableNetworkSessionCollection> wrapper)
+            {
+                return wrapper.GetResult();
+            }
+            throw new ArgumentException("Invalid async result", nameof(asyncResult));
+        }
+
+        /// <summary>
+        /// Begins joining a network session.
+        /// </summary>
+        public static IAsyncResult BeginJoin(
+            AvailableNetworkSession availableSession,
+            AsyncCallback callback,
+            object asyncState)
+        {
+            var task = Task.Run(() =>
+            {
+                // Mock implementation - create a new session as a client
+                var session = new NetworkSession(availableSession.SessionType, availableSession.CurrentGamerCount, 0, false);
+                session.sessionState = NetworkSessionState.Lobby;
+                return session;
+            });
+
+            return new AsyncResultWrapper<NetworkSession>(task, callback, asyncState);
+        }
+
+        /// <summary>
+        /// Ends the join session operation.
+        /// </summary>
+        public static NetworkSession EndJoin(IAsyncResult asyncResult)
+        {
+            if (asyncResult is AsyncResultWrapper<NetworkSession> wrapper)
+            {
+                return wrapper.GetResult();
+            }
+            throw new ArgumentException("Invalid async result", nameof(asyncResult));
+        }
+
+        /// <summary>
+        /// Begins joining an invited session.
+        /// </summary>
+        public static IAsyncResult BeginJoinInvited(int maxLocalGamers, AsyncCallback callback, object asyncState)
+        {
+            var task = Task.Run(() =>
+            {
+                // Mock implementation
+                var session = new NetworkSession(NetworkSessionType.PlayerMatch, 8, 0, false);
+                session.sessionState = NetworkSessionState.Lobby;
+                // Fire invite accepted event - pass a mock gamer
+                InviteAccepted?.Invoke(null, new InviteAcceptedEventArgs(GamerServices.SignedInGamer.Current, false));
+                return session;
+            });
+
+            return new AsyncResultWrapper<NetworkSession>(task, callback, asyncState);
+        }
+
+        public static IAsyncResult BeginJoinInvited(
+            IEnumerable<SignedInGamer> localGamers,
+            AsyncCallback callback,
+            object asyncState
+        )
+        {
+            throw new NotImplementedException();
+        }
+
+		/// <summary>
+		/// Ends the join invited session operation.
+		/// </summary>
+		public static NetworkSession EndJoinInvited(IAsyncResult asyncResult)
+        {
+            return EndJoin(asyncResult);
+        }
+
+        /// <summary>
+        /// Creates a new network session synchronously.
+        /// </summary>
+        /// <param name="sessionType">The type of session to create.</param>
+        /// <param name="maxLocalGamers">Maximum number of local gamers.</param>
+        /// <param name="maxGamers">Maximum total number of gamers.</param>
+        /// <param name="privateGamerSlots">Number of private gamer slots.</param>
+        /// <param name="sessionProperties">Session properties.</param>
+        /// <returns>The created network session.</returns>
+        public static NetworkSession Create(NetworkSessionType sessionType, int maxLocalGamers, int maxGamers, int privateGamerSlots, IDictionary<string, object> sessionProperties)
+        {
+            var props = new NetworkSessionProperties();
+            if (sessionProperties != null)
+            {
+                foreach (var kvp in sessionProperties)
+                {
+                    props[kvp.Key] = kvp.Value;
+                }
+            }
+            var asyncResult = BeginCreate(sessionType, maxLocalGamers, maxGamers, privateGamerSlots, props);
+            return EndCreate(asyncResult);
+        }
+
+        /// <summary>
+        /// Creates a new network session synchronously with default properties.
+        /// </summary>
+        /// <param name="sessionType">The type of session to create.</param>
+        /// <param name="maxLocalGamers">Maximum number of local gamers.</param>
+        /// <param name="maxGamers">Maximum total number of gamers.</param>
+        /// <returns>The created network session.</returns>
+        public static NetworkSession Create(NetworkSessionType sessionType, int maxLocalGamers, int maxGamers)
+        {
+            return Create(sessionType, maxLocalGamers, maxGamers, 0, new Dictionary<string, object>());
+        }
+
+        /// <summary>
+        /// Finds available network sessions synchronously.
+        /// </summary>
+        /// <param name="sessionType">The type of sessions to find.</param>
+        /// <param name="maxLocalGamers">Maximum number of local gamers.</param>
+        /// <param name="sessionProperties">Session properties to search for.</param>
+        /// <returns>Collection of available sessions.</returns>
+        public static AvailableNetworkSessionCollection Find(NetworkSessionType sessionType, int maxLocalGamers, IDictionary<string, object> sessionProperties)
+        {
+            var props = new NetworkSessionProperties();
+            if (sessionProperties != null)
+            {
+                foreach (var kvp in sessionProperties)
+                {
+                    props[kvp.Key] = kvp.Value;
+                }
+            }
+            var asyncResult = BeginFind(sessionType, maxLocalGamers, props, null, null);
+            return EndFind(asyncResult);
+        }
+
+        /// <summary>
+        /// Finds available network sessions synchronously with default properties.
+        /// </summary>
+        /// <param name="sessionType">The type of sessions to find.</param>
+        /// <param name="maxLocalGamers">Maximum number of local gamers.</param>
+        /// <returns>Collection of available sessions.</returns>
+        public static AvailableNetworkSessionCollection Find(NetworkSessionType sessionType, int maxLocalGamers)
+        {
+            return Find(sessionType, maxLocalGamers, new Dictionary<string, object>());
+        }
+
+        /// <summary>
+        /// Joins an available network session synchronously.
+        /// </summary>
+        /// <param name="availableSession">The session to join.</param>
+        /// <returns>The joined network session.</returns>
+        public static NetworkSession Join(AvailableNetworkSession availableSession)
+        {
+            var asyncResult = BeginJoin(availableSession, null, null);
+            return EndJoin(asyncResult);
+        }
+
+        /// <summary>
+        /// Updates the network session.
+        /// </summary>
+        public void Update()
+        {
+            if (disposed)
+                return;
+
+            // Process any pending network messages
+            ProcessIncomingMessages();
+        }
+
+        /// <summary>
+        /// Sends data to all gamers in the session.
+        /// </summary>
+        public void SendToAll(PacketWriter writer, SendDataOptions options)
+        {
+            SendToAll(writer, options, NetworkGamer.LocalGamer);
+        }
+
+        /// <summary>
+        /// Sends data to all gamers except the specified sender.
+        /// </summary>
+        public void SendToAll(PacketWriter writer, SendDataOptions options, NetworkGamer sender)
+        {
+            if (writer == null)
+                throw new ArgumentNullException(nameof(writer));
+
+            byte[] data = writer.GetData();
+            
+            lock (lockObject)
+            {
+                foreach (var gamer in gamers)
+                {
+                    if (gamer != sender && !gamer.IsLocal)
+                    {
+                        SendDataToGamer(gamer, data, options);
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Starts the game.
+        /// </summary>
+        public void StartGame()
+        {
+            if (sessionState == NetworkSessionState.Lobby)
+            {
+                sessionState = NetworkSessionState.Playing;
+                OnGameStarted();
+            }
+        }
+
+        /// <summary>
+        /// Ends the game and returns to lobby.
+        /// </summary>
+        public void EndGame()
+        {
+            if (sessionState == NetworkSessionState.Playing)
+            {
+                sessionState = NetworkSessionState.Lobby;
+                OnGameEnded();
+            }
+        }
+
+        /// <summary>
+        /// Notifies when a gamer's readiness changes.
+        /// </summary>
+        internal void NotifyReadinessChanged(NetworkGamer gamer)
+        {
+            // Send readiness update to other players
+            if (IsHost)
+            {
+                var writer = new PacketWriter();
+                writer.Write("ReadinessUpdate");
+                writer.Write(gamer.Id);
+                writer.Write(gamer.IsReady);
+                SendToAll(writer, SendDataOptions.Reliable, gamer);
+            }
+        }
+
+        /// <summary>
+        /// Sends data to a specific gamer.
+        /// </summary>
+        internal void SendDataToGamer(NetworkGamer gamer, PacketWriter writer, SendDataOptions options)
+        {
+            SendDataToGamer(gamer, writer.GetData(), options);
+        }
+
+        private void SendDataToGamer(NetworkGamer gamer, byte[] data, SendDataOptions options)
+        {
+            if (gamerEndpoints.TryGetValue(gamer.Id, out IPEndPoint endpoint))
+            {
+                try
+                {
+                    udpClient.Send(data, data.Length, endpoint);
+                }
+                catch (Exception ex)
+                {
+                    // Log the error but don't crash the game
+                    System.Diagnostics.Debug.WriteLine($"Failed to send data to {gamer.Gamertag}: {ex.Message}");
+                }
+            }
+        }
+
+        private void AddGamer(NetworkGamer gamer)
+        {
+            lock (lockObject)
+            {
+                gamers.Add(gamer);
+            }
+            OnGamerJoined(gamer);
+        }
+
+        private void RemoveGamer(NetworkGamer gamer)
+        {
+            lock (lockObject)
+            {
+                gamers.Remove(gamer);
+                gamerEndpoints.Remove(gamer.Id);
+            }
+            OnGamerLeft(gamer);
+        }
+
+        private void ProcessIncomingMessages()
+        {
+            // Mock implementation - in a real scenario this would process UDP messages
+        }
+
+        private void OnGameStarted()
+        {
+            GameStarted?.Invoke(this, new GameStartedEventArgs());
+        }
+
+        private void OnGameEnded()
+        {
+            GameEnded?.Invoke(this, new GameEndedEventArgs());
+        }
+
+        private void OnGamerJoined(NetworkGamer gamer)
+        {
+            GamerJoined?.Invoke(this, new GamerJoinedEventArgs(gamer));
+        }
+
+        private void OnGamerLeft(NetworkGamer gamer)
+        {
+            GamerLeft?.Invoke(this, new GamerLeftEventArgs(gamer));
+        }
+
+        private void OnSessionEnded(NetworkSessionEndReason reason)
+        {
+            sessionState = NetworkSessionState.Ended;
+            SessionEnded?.Invoke(this, new NetworkSessionEndedEventArgs(reason));
+        }
+
+        /// <summary>
+        /// Disposes the network session.
+        /// </summary>
+        public void Dispose()
+        {
+            if (!disposed)
+            {
+                cancellationTokenSource?.Cancel();
+                receiveTask?.Wait(1000); // Wait up to 1 second
+                
+                udpClient?.Close();
+                udpClient?.Dispose();
+                cancellationTokenSource?.Dispose();
+                
+                OnSessionEnded(NetworkSessionEndReason.ClientSignedOut);
+                disposed = true;
+            }
+        }
+    }
+}

MonoGame.Xna.Framework.Net/Net/PacketReader.cs

@@ -0,0 +1,241 @@
+using System;
+using System.IO;
+using System.Text;
+using Microsoft.Xna.Framework;
+
+namespace Microsoft.Xna.Framework.Net
+{
+    /// <summary>
+    /// Reads network data packets in a format compatible with XNA's PacketReader.
+    /// </summary>
+    public class PacketReader : IDisposable
+    {
+        private readonly MemoryStream stream;
+        private readonly BinaryReader reader;
+        private bool disposed;
+
+        /// <summary>
+        /// Initializes a new PacketReader from byte data.
+        /// </summary>
+        internal PacketReader(byte[] data)
+        {
+            stream = new MemoryStream(data);
+            reader = new BinaryReader(stream, Encoding.UTF8);
+        }
+
+        /// <summary>
+        /// Initializes a new empty PacketReader.
+        /// </summary>
+        public PacketReader()
+        {
+            stream = new MemoryStream();
+            reader = new BinaryReader(stream, Encoding.UTF8);
+        }
+
+        /// <summary>
+        /// Gets the length of the packet data.
+        /// </summary>
+        public int Length => (int)stream.Length;
+
+        /// <summary>
+        /// Gets the current position in the packet data.
+        /// </summary>
+        public int Position
+        {
+            get => (int)stream.Position;
+            set => stream.Position = value;
+        }
+
+        /// <summary>
+        /// Gets the number of bytes remaining to be read.
+        /// </summary>
+        public int BytesRemaining => Length - Position;
+
+        /// <summary>
+        /// Reads a boolean value.
+        /// </summary>
+        public bool ReadBoolean()
+        {
+            return reader.ReadBoolean();
+        }
+
+        /// <summary>
+        /// Reads a byte value.
+        /// </summary>
+        public byte ReadByte()
+        {
+            return reader.ReadByte();
+        }
+
+        /// <summary>
+        /// Reads a signed byte value.
+        /// </summary>
+        public sbyte ReadSByte()
+        {
+            return reader.ReadSByte();
+        }
+
+        /// <summary>
+        /// Reads a 16-bit integer.
+        /// </summary>
+        public short ReadInt16()
+        {
+            return reader.ReadInt16();
+        }
+
+        /// <summary>
+        /// Reads an unsigned 16-bit integer.
+        /// </summary>
+        public ushort ReadUInt16()
+        {
+            return reader.ReadUInt16();
+        }
+
+        /// <summary>
+        /// Reads a 32-bit integer.
+        /// </summary>
+        public int ReadInt32()
+        {
+            return reader.ReadInt32();
+        }
+
+        /// <summary>
+        /// Reads an unsigned 32-bit integer.
+        /// </summary>
+        public uint ReadUInt32()
+        {
+            return reader.ReadUInt32();
+        }
+
+        /// <summary>
+        /// Reads a 64-bit integer.
+        /// </summary>
+        public long ReadInt64()
+        {
+            return reader.ReadInt64();
+        }
+
+        /// <summary>
+        /// Reads an unsigned 64-bit integer.
+        /// </summary>
+        public ulong ReadUInt64()
+        {
+            return reader.ReadUInt64();
+        }
+
+        /// <summary>
+        /// Reads a single-precision floating point value.
+        /// </summary>
+        public float ReadSingle()
+        {
+            return reader.ReadSingle();
+        }
+
+        /// <summary>
+        /// Reads a double-precision floating point value.
+        /// </summary>
+        public double ReadDouble()
+        {
+            return reader.ReadDouble();
+        }
+
+        /// <summary>
+        /// Reads a string value.
+        /// </summary>
+        public string ReadString()
+        {
+            return reader.ReadString();
+        }
+
+        /// <summary>
+        /// Reads a Vector2 value.
+        /// </summary>
+        public Vector2 ReadVector2()
+        {
+            return new Vector2(reader.ReadSingle(), reader.ReadSingle());
+        }
+
+        /// <summary>
+        /// Reads a Vector3 value.
+        /// </summary>
+        public Vector3 ReadVector3()
+        {
+            return new Vector3(reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle());
+        }
+
+        /// <summary>
+        /// Reads a Vector4 value.
+        /// </summary>
+        public Vector4 ReadVector4()
+        {
+            return new Vector4(reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle());
+        }
+
+        /// <summary>
+        /// Reads a Quaternion value.
+        /// </summary>
+        public Quaternion ReadQuaternion()
+        {
+            return new Quaternion(reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle());
+        }
+
+        /// <summary>
+        /// Reads a Matrix value.
+        /// </summary>
+        public Matrix ReadMatrix()
+        {
+            return new Matrix(
+                reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(),
+                reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(),
+                reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(),
+                reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle(), reader.ReadSingle()
+            );
+        }
+
+        /// <summary>
+        /// Reads a Color value.
+        /// </summary>
+        public Color ReadColor()
+        {
+            return new Color(reader.ReadByte(), reader.ReadByte(), reader.ReadByte(), reader.ReadByte());
+        }
+
+        /// <summary>
+        /// Reads a byte array.
+        /// </summary>
+        public byte[] ReadBytes()
+        {
+            int length = reader.ReadInt32();
+            return reader.ReadBytes(length);
+        }
+
+        /// <summary>
+        /// Reads a specified number of bytes.
+        /// </summary>
+        public byte[] ReadBytes(int count)
+        {
+            return reader.ReadBytes(count);
+        }
+
+        /// <summary>
+        /// Closes the packet reader.
+        /// </summary>
+        public void Close()
+        {
+            Dispose();
+        }
+
+        /// <summary>
+        /// Disposes the packet reader.
+        /// </summary>
+        public void Dispose()
+        {
+            if (!disposed)
+            {
+                reader?.Dispose();
+                stream?.Dispose();
+                disposed = true;
+            }
+        }
+    }
+}

MonoGame.Xna.Framework.Net/Net/PacketWriter.cs

@@ -0,0 +1,260 @@
+using System;
+using System.IO;
+using System.Text;
+using Microsoft.Xna.Framework;
+
+namespace Microsoft.Xna.Framework.Net
+{
+    /// <summary>
+    /// Writes network data packets in a format compatible with XNA's PacketWriter.
+    /// </summary>
+    public class PacketWriter : IDisposable
+    {
+        private readonly MemoryStream stream;
+        private readonly BinaryWriter writer;
+        private bool disposed;
+
+        /// <summary>
+        /// Initializes a new PacketWriter.
+        /// </summary>
+        public PacketWriter()
+        {
+            stream = new MemoryStream();
+            writer = new BinaryWriter(stream, Encoding.UTF8);
+        }
+
+        /// <summary>
+        /// Gets the length of the packet data.
+        /// </summary>
+        public int Length => (int)stream.Length;
+
+        /// <summary>
+        /// Gets the position in the packet data.
+        /// </summary>
+        public int Position
+        {
+            get => (int)stream.Position;
+            set => stream.Position = value;
+        }
+
+        /// <summary>
+        /// Writes a boolean value.
+        /// </summary>
+        public void Write(bool value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a byte value.
+        /// </summary>
+        public void Write(byte value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a signed byte value.
+        /// </summary>
+        public void Write(sbyte value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a 16-bit integer.
+        /// </summary>
+        public void Write(short value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes an unsigned 16-bit integer.
+        /// </summary>
+        public void Write(ushort value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a 32-bit integer.
+        /// </summary>
+        public void Write(int value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes an unsigned 32-bit integer.
+        /// </summary>
+        public void Write(uint value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a 64-bit integer.
+        /// </summary>
+        public void Write(long value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes an unsigned 64-bit integer.
+        /// </summary>
+        public void Write(ulong value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a single-precision floating point value.
+        /// </summary>
+        public void Write(float value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a double-precision floating point value.
+        /// </summary>
+        public void Write(double value)
+        {
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a string value.
+        /// </summary>
+        public void Write(string value)
+        {
+            if (value == null)
+                throw new ArgumentNullException(nameof(value));
+            writer.Write(value);
+        }
+
+        /// <summary>
+        /// Writes a Vector2 value.
+        /// </summary>
+        public void Write(Vector2 value)
+        {
+            writer.Write(value.X);
+            writer.Write(value.Y);
+        }
+
+        /// <summary>
+        /// Writes a Vector3 value.
+        /// </summary>
+        public void Write(Vector3 value)
+        {
+            writer.Write(value.X);
+            writer.Write(value.Y);
+            writer.Write(value.Z);
+        }
+
+        /// <summary>
+        /// Writes a Vector4 value.
+        /// </summary>
+        public void Write(Vector4 value)
+        {
+            writer.Write(value.X);
+            writer.Write(value.Y);
+            writer.Write(value.Z);
+            writer.Write(value.W);
+        }
+
+        /// <summary>
+        /// Writes a Quaternion value.
+        /// </summary>
+        public void Write(Quaternion value)
+        {
+            writer.Write(value.X);
+            writer.Write(value.Y);
+            writer.Write(value.Z);
+            writer.Write(value.W);
+        }
+
+        /// <summary>
+        /// Writes a Matrix value.
+        /// </summary>
+        public void Write(Matrix value)
+        {
+            writer.Write(value.M11); writer.Write(value.M12); writer.Write(value.M13); writer.Write(value.M14);
+            writer.Write(value.M21); writer.Write(value.M22); writer.Write(value.M23); writer.Write(value.M24);
+            writer.Write(value.M31); writer.Write(value.M32); writer.Write(value.M33); writer.Write(value.M34);
+            writer.Write(value.M41); writer.Write(value.M42); writer.Write(value.M43); writer.Write(value.M44);
+        }
+
+        /// <summary>
+        /// Writes a Color value.
+        /// </summary>
+        public void Write(Color value)
+        {
+            writer.Write(value.R);
+            writer.Write(value.G);
+            writer.Write(value.B);
+            writer.Write(value.A);
+        }
+
+        /// <summary>
+        /// Writes raw byte data.
+        /// </summary>
+        public void Write(byte[] buffer)
+        {
+            if (buffer == null)
+                throw new ArgumentNullException(nameof(buffer));
+            writer.Write(buffer.Length);
+            writer.Write(buffer);
+        }
+
+        /// <summary>
+        /// Writes a portion of a byte array.
+        /// </summary>
+        public void Write(byte[] buffer, int offset, int count)
+        {
+            if (buffer == null)
+                throw new ArgumentNullException(nameof(buffer));
+            writer.Write(count);
+            writer.Write(buffer, offset, count);
+        }
+
+        /// <summary>
+        /// Gets the packet data as a byte array.
+        /// </summary>
+        internal byte[] GetData()
+        {
+            return stream.ToArray();
+        }
+
+        /// <summary>
+        /// Creates a packet reader for the current data.
+        /// </summary>
+        internal PacketReader CreateReader()
+        {
+            return new PacketReader(GetData());
+        }
+
+        /// <summary>
+        /// Closes the packet writer.
+        /// </summary>
+        public void Close()
+        {
+            Dispose();
+        }
+
+        /// <summary>
+        /// Disposes the packet writer.
+        /// </summary>
+        public void Dispose()
+        {
+            if (!disposed)
+            {
+                writer?.Dispose();
+                stream?.Dispose();
+                disposed = true;
+            }
+        }
+    }
+}