问题描述
我正在尝试使用 setTrafficClass 标记 DSCP 值.我在两台不同的机器上设置了服务器和客户端,我可以打印 DSCP 的值,但我在 WireShark 中看不到它.我在网上浏览了一些帖子,但没有任何帮助.我正在使用 Windows 7 专业版.任何帮助,将不胜感激.谢谢!
I am trying to mark DSCP values using setTrafficClass. I have server and client set up on two different machines and I am able to print value of DSCP but I can not see it in WireShark. I have gone through some posts online but nothing helped. I am using Windows 7 professional. Any help would be appreciated. Thank you!
我正在进行更多测试,看看如何做到这一点.这是客户端代码:
I am more testing to see how this can be done. Here is the client code:
试试{
Socket socket = new Socket(addr, 2345); socket.setTrafficClass(10); PrintWriter out = new PrintWriter( socket.getOutputStream(), true); out.println("Current DSCP value: " + socket.getTrafficClass()); out.close(); socket.close(); } catch (Exception e) { e.printStackTrace(); } }
服务器:
try { ServerSocket serverSocket = new ServerSocket(1234); Socket clientSocket = serverSocket.accept(); BufferedReader in = new BufferedReader(new InputStreamReader( clientSocket.getInputStream())); String fromClient = in.readLine(); System.out.println(fromClient); in.close(); clientSocket.close(); serverSocket.close(); } catch (Exception e) { e.printStackTrace(); } }
在服务器端的控制台中:当前DSCP值:10
In console on server side: Current DSCP value: 10
我的服务器代码和客户端位于不同的机器上.
My server code and client are on separate machines.
在wireshark中我看到了:
In wireshark I see:
区分服务字段:0x00(DSCP 0x00:默认;ECN:0x00:非 ECT(不支持 ECN 传输))
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00: Not-ECT (Not ECN-Capable Transport))
我希望看到 wireshark 的变化,我只看到默认值为零.
I expect to see changes in wireshark and I only see default value zero.
推荐答案
上次我在 Java 中使用 DSCP 值时,必须将 java.net.preferIPv4Stack 系统属性设置为 true 由于 JVM 中的错误.尽管似乎在 java.net.Socket API 中工作,但不会在底层套接字上设置 DSCP 值.
Last time I worked with DSCP values in Java one had to set the java.net.preferIPv4Stack system property to true due to a bug in the JVM. Othwerwise DSCP values would not be set on the underlying socket despite appearing to work in the java.net.Socket API.
另外你可能需要在连接socket之前调用setTrafficClass,在某些平台上连接后可能无法工作.
Also you may have to call setTrafficClass before connecting the socket, it may not work after connection on some platforms.
java -Djava.net.preferIPv4Stack=true ...