Problem with setTraficClass() in Linux machine

Question

Hi
We are facing some problem with setTraficClass() method in java.net.Socket . When we try to set a value 34 using this method in windows it is not setting. when try to see the Ip header in the packet using wireshark it is showing 00.
After lot of googling we found in sun forum that in Windows os there is no support for TOS/DSCP. if we want to set a value we need to add a registry parameter. Now it is setting in Windows XP [http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4696356]
But our problem is we are trying to run the same thing on linux machine RedHat 2.6.18.92.e15-pae-1686 it is setting 00 . Please find the code bellow
Is there any setting we need to do in linux machine to call the setTraficClass() method. I am new to linux and not able to fix this issue.
Please help me
Thanks in advance.
Sethu
Server code
import java.net.*;
import java.io.*;
class server
public static void main(String args[]) throws Exception
byte[] receive_data = new byte[1024];
byte[] send_data = new byte[1024];
int recv_port;
DatagramSocket server_socket = new DatagramSocket(5000);
System.out.println ("UDPServer Waiting for client on port 5000");
while(true)
DatagramPacket receive_packet = new DatagramPacket(receive_data,
receive_data.length);
server_socket.receive(receive_packet);
server_socket.getTraficClass()
String data = new String(receive_packet.getData(),0 ,0
,receive_packet.getLength());
System.out.println("socketIP"+server_socket.getTrafficClass());
server_socket.setTrafficClass(0x18);
InetAddress IPAddress = receive_packet.getAddress();
recv_port = receive_packet.getPort();
if (data.equals("q") || data.equals("Q"))
break;
else
System.out.println("( " + IPAddress + " , " + recv_port
+ " ) said :" + data );
Client code
import java.net.*;
import java.io.*;
class Client
public static void main(String args[]) throws Exception
byte[] send_data = new byte[1024];
BufferedReader infromuser =
new BufferedReader(new InputStreamReader(System.in));
DatagramSocket client_socket = new DatagramSocket();
InetAddress IPAddress = InetAddress.getByName("127.0.0.1");
while (true)
System.out.println("Type Something (q or Q to quit): ");
String data = infromuser.readLine();
if (data.equals("q") || data.equals("Q"))
break;
else
send_data = data.getBytes();
DatagramPacket send_packet = new DatagramPacket(send_data,
send_data.length,
IPAddress, 5000);
client_socket.setTraficClass(34)
client_socket.send(send_packet);
client_socket.close();

Answer 1

Hi,
when I use setsockopt() API on linux machine. I am able to set the DSCP value in the UDP socket.
I can see the visibility of DSCP marking on the wireShark.
when I use the setTraficClass(34) API on linux machine. I am not able to set the DSCP value in the UDP socket. It
always takes the default value as 0. I cant see the visibility of DSCP marking on the wireShark.
setSockopt() API supported in Linux machine. Why not SetTrafficClass() API?.
Is there any changes required to make the SetTrafficClass() API to work on Linux platform?.