Tracing of channel variables

[Kalle Tuulos]

Question in short: how can channel variables, e.g. Wirestate, be traced?

I'm using the "src/csma/examples/csma-ping.cc" as an example. In this example, 4 Csma devices connect to the same Csma channel. According to manual's Tracing chapter, steps would be:

First, modify the "csma-channel.h" file. Add following:

#include "ns3/traced-value.h"

#include "ns3/trace-source-accessor.h"

Modify the definition of m_state to be:

TracedValue<WireState> m_state;

Then, add trace source. For this, edit the "csma-channel.cc", GetTypeId function.

    .AddTraceSource ("ChannelState", "Channel state",

     MakeTraceSourceAccessor (&CsmaChannel::m_state))

Then, create a tracing function. This will be added to "csma-ping.cc" file.

static void

ChannelStateTrace ( WireState oldValue, SatelWireState newValue )

{

  std::string filename = "channel_state_trace.txt";

  std::ofstream outFile;

  outFile.open (filename.c_str (), std::ios_base::out | std::ios_base::trunc);

  if (!outFile.is_open ())

    {

      NS_LOG_ERROR ("Can't open file " << filename);

      return;

    }

  outFile << Simulator::Now() << " Old value " << oldValue << " New " << newValue << std::endl;

}

But after this, I don't know, how I can activate the tracing. The manual suggests to use myObject->TraceConnectWithoutContext () but the csma-ping.cc's main function is not aware of CsmaChannel object, thus it can't call its TraceConnectWithoutContext function.

So, back to the question: how channel's activity can be traced?

Thanks and best regards,

   Kalle

xx

[Kalle Tuulos]

Ok, I found the solution. The key was, that Config::Connect should be mapped to "ChannelList".

Attached is ns-3.29 patch with necessary modifications to enable tracing. WireState traces are printed to screen from the csma-ping.cc examle. There is also patch to ping to print packet sizes properly.

BR,

  Kalle