TCP/IP の代わりに UDP プロトコルの使用を検討する必要があります。
http://en.wikipedia.org/wiki/User_Datagram_Protocol
クライアントのコードは次のとおりです。
using System.Net;
using System.Net.Sockets;
...
/// <summary>
/// Sends a sepcified number of UDP packets to a host or IP Address.
/// </summary>
/// <param name="hostNameOrAddress">The host name or an IP Address to which the UDP packets will be sent.</param>
/// <param name="destinationPort">The destination port to which the UDP packets will be sent.</param>
/// <param name="data">The data to send in the UDP packet.</param>
/// <param name="count">The number of UDP packets to send.</param>
public static void SendUDPPacket(string hostNameOrAddress, int destinationPort, string data, int count)
{
// Validate the destination port number
if (destinationPort < 1 || destinationPort > 65535)
throw new ArgumentOutOfRangeException("destinationPort", "Parameter destinationPort must be between 1 and 65,535.");
// Resolve the host name to an IP Address
IPAddress[] ipAddresses = Dns.GetHostAddresses(hostNameOrAddress);
if (ipAddresses.Length == 0)
throw new ArgumentException("Host name or address could not be resolved.", "hostNameOrAddress");
// Use the first IP Address in the list
IPAddress destination = ipAddresses[0];
IPEndPoint endPoint = new IPEndPoint(destination, destinationPort);
byte[] buffer = Encoding.ASCII.GetBytes(data);
// Send the packets
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
for(int i = 0; i < count; i++)
socket.SendTo(buffer, endPoint);
socket.Close();
}