System.Net.Sockets.Socket.SendTo C# (CSharp) Method

        public int SendTo(byte[] buffer, EndPoint remoteEP)
        {
            return SendTo(buffer, 0, buffer != null ? buffer.Length : 0, SocketFlags.None, remoteEP);
        }

 static void Main(string[] args)
 {
     Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
     IPEndPoint iep = new IPEndPoint(IPAddress.Any, 9000);
     s.Bind(iep);
     EndPoint remote = (EndPoint)iep;
     byte[] data = new byte[1024];
     int k = s.ReceiveFrom(data, ref remote);
     Console.WriteLine("Loi chao tu Client:{0}",Encoding.ASCII.GetString(data,0,k));
     data = new byte[1024];
     data = Encoding.ASCII.GetBytes("Chao Client ket noi");
     s.SendTo(data, remote);
     while (true)
     {
         data = new byte[1024];
         string st;
         k=s.ReceiveFrom(data, ref remote);
         st = Encoding.ASCII.GetString(data, 0, k);
         Console.WriteLine("Du lieu tu Client Gui la:{0}", st);
         if (st.ToUpper().Equals("QUIT"))
             break;
         st = st.ToUpper();
         data = new byte[1024];
         data = Encoding.ASCII.GetBytes(st);
         s.SendTo(data, remote);
     }
     s.Close();
 }