Networking Core APIs

System.Net.Sockets

The foundational namespace for low-level network communication in .NET. It provides classes for working with sockets, enabling direct control over network connections.

Key Classes:

• Socket: The core class for sending and receiving data on a network. Supports both connection-oriented (TCP) and connectionless (UDP) protocols.
• TcpListener: A simple class to listen for incoming TCP connection requests.
• TcpClient: Provides a client-side connection to a remote host using TCP.
• UdpClient: For sending and receiving UDP datagrams.

Common Scenarios:

• Implementing custom client-server architectures.
• Building peer-to-peer networking solutions.
• Handling raw data transmission.

// Example: Basic TCP Server setup
using System.Net.Sockets;
using System.Text;

// ...

TcpListener server = new TcpListener(IPAddress.Any, 11000);
server.Start();

Console.WriteLine("Waiting for a connection...");
Socket client = await server.AcceptSocketAsync();
Console.WriteLine("Connected!");

NetworkStream stream = new NetworkStream(client);
byte[] buffer = new byte[1024];
int bytesRead = await stream.ReadAsync(buffer, 0, buffer.Length);
string message = Encoding.ASCII.GetString(buffer, 0, bytesRead);
Console.WriteLine($"Received: {message}");

stream.Close();
client.Close();
server.Stop();

                

System.Net.WebSockets

Provides support for the WebSocket protocol, offering a full-duplex communication channel over a single TCP connection. Ideal for real-time, interactive applications like online games.

Key Classes:

• ClientWebSocket: Represents a WebSocket client.
• WebSocketServer (conceptual, typically implemented using ASP.NET Core or other frameworks): Represents a WebSocket server.

Advantages for Gaming:

• Lower overhead compared to HTTP polling.
• Full-duplex communication allows for efficient sending and receiving of game state updates.
• Suitable for real-time game events and chat.

Higher-Level Libraries

For many game development scenarios, directly using low-level sockets can be complex and error-prone. Several higher-level libraries abstract away these complexities, offering features specifically tailored for games.

Popular Options:

• LiteNetLib: A cross-platform, reliable UDP network library for .NET. It provides features like reliability, ordering, and fragmentation over UDP.
• Mirror Networking: A popular, open-source networking solution for Unity, built on top of Unity's Transport layer (which can use sockets).
• Photon PUN (Photon Unity Networking): A widely used third-party SDK for building multiplayer games in Unity, offering robust matchmaking and real-time networking.

These libraries often handle common networking challenges such as:

• Connection management and disconnection handling.
• Data serialization and deserialization.
• Latency compensation and prediction.
• Reliable messaging over UDP.
• NAT traversal.