Question about SetSocketOption & MulticastOption

本文关键字：MulticastOption amp about SetSocketOption Question | 更新日期: 2023-09-27 17:59:32

我创建了一个组&在方法CCD_ 1通过创建线程等待消息之前1行发送消息。此代码完美地运行。我只是想知道，在我尝试向组发送内容之前，为什么不在Send方法中也添加这一行，用于将套接字加入组。

server.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, MulticastOption);

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
class MAIN
{
    private static MulticastOption CreateGroup()
    {
        return new MulticastOption(IPAddress.Parse("224.100.0.1"));
    }
    private static void Receive(MulticastOption MulticastOption)
    {
        Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
        IPEndPoint iep = new IPEndPoint(IPAddress.Any, 9050);
        EndPoint ep = (EndPoint)iep;
        sock.Bind(iep);
        sock.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, MulticastOption);
        //
        byte[] data = new byte[1024];
        new Thread(new ThreadStart(Send)).Start();
        int recv = sock.ReceiveFrom(data, ref ep);
        String stringData = Encoding.ASCII.GetString(data, 0, recv);
        Console.WriteLine("received: {0} from: {1}", stringData, ep.ToString());
        sock.Close();
    }
    private static void Send()
    {
        Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
        IPEndPoint iep = new IPEndPoint(IPAddress.Parse("224.100.0.1"), 9050);

        byte[] data = Encoding.ASCII.GetBytes("This is a test message");
        server.SendTo(data, iep);
        server.Close();
    }
    public static void Main(String[] args)
    {
        Receive(CreateGroup());
        Console.ReadKey();
    }
}

Question about SetSocketOption & MulticastOption

来自本文：

IP_ADD_MEMBERSHIP选项允许您要加入多播组由中的主机组地址指定多播地址结构。你必须加入组才能接收多播数据报您不需要加入组发送多播数据报

但是，由于默认的TTL值，这只能在本地子网上工作。请参阅本文以获得更明确的答案。

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