## Trace files...

Moderator: Praktikum: Internet

EvilHyperion
Neuling
Beiträge: 2
Registriert: 24. Jan 2008 20:19

### Trace files...

Hey,

two more problems:
1) I don't really get how the netmon is working... Following the examples from the slides it should be able to draw the packet loss using the function L(). However, how does the program calculate the package loss from just one argument? aren't there at least two arguments mandatory? Well, and if this works with sequences numbers or so, where has even been explained who exactly?

Using 1.trace and 2.trace from the standard configuration the netmon should be able to draw the package loss from 2.trace in comparison to 1.trace, right? I don't get him to do this for me...

2) receiver.trace is always empty for me. Although I correctly us emit_up(msg) in my handler the packages never seem to get to the receiving service... What might be the reason for this?

Thx.

mjp
Neuling
Beiträge: 7
Registriert: 16. Apr 2006 11:34

### Re: Trace files...

Hi,
EvilHyperion hat geschrieben: 1) I don't really get how the netmon is working... Following the examples from the slides it should be able to draw the packet loss using the function L(). However, how does the program calculate the package loss from just one argument? aren't there at least two arguments mandatory? Well, and if this works with sequences numbers or so, where has even been explained who exactly?

Thx.
My impression is that we can only detect the package loss by using L(receiver). I take it that a 'package loss' means that a message sent by TestSender did not arrive at TestReceiver, because our FEC failed. To your question about how to use the sequence numbers in order to display the package loss: As far as I understand the necessary code is given in the files 'TestSender.java' and 'TestReceiver'.java in 'samples/handlers/praktikum/'. We only copied these two files and used them for our program. The code-lines in the TestReceiver.java can be found in 'public void received(Message msg, MessageContext ctx)':

Code: Alles auswählen

os.writeInt(16);
os.writeLong(System.currentTimeMillis());
os.writeInt(sz);
os.writeInt(map.getInt("seq"));
This is the information written in the 'receiver.trace'. The last line extracts the sequence number of the message, which was stored in there by the TestSender.
Our problem/question is that we only took the code from 'TestSender.java' and 'TestReceiver'.java in 'samples/handlers/praktikum/'. We are not shure if it is correct that we do not have to implement anything else in order to display the package loss in NetMon. However we can't see what else we should do. The question to Mr. Aitenbichler, is this correct?

Yours, mjp

erwin.ait
Erstie
Beiträge: 20
Registriert: 23. Jul 2007 16:34

### Re: Trace files...

You don't have to implement more regarding NetMon. However, your receiver program should
- directly determine the loss rate and print it to the console
- check that no messages were duplicated
- check that the contents of all messages are correct