Calculate Packet Received time in ns3

Question

I have the following code in c++ in ns3 used when a packet is received to print its content and its arrival time using

    Simulator::Now ().GetSeconds() 

but it turns zeros every time. Can anyone tell me why? and how can I get the real time?

Ptr<const Packet> p = packet;
LrWpanMacHeader h;
p->PeekHeader(h); //remove the header in order to print packet 
    content, so that's why the size differ between packet and p
    BasicPacketData bpd (p);
std::cout<<"Packet Size:"<<p->GetSize()<<std::endl;
uint8_t *buffer = new uint8_t[p->GetSize()];
p->CopyData (buffer, p->GetSize());
std::string receivedData(buffer, buffer+p->GetSize ());
std::cout<<"Received:"<<receivedData.c_str()<<std::endl;


if(!h.IsAcknowledgment()) //Returns true if the header is an ack
{

    NS_LOG_UNCOND ("----------Packet received----------\n"
            << "Packet of size " << bpd.size << " bytes received\n"
            << "on device with address "<< dev3->GetMac()->GetShortAddress()<<"\n"
            << "was sent from address " << dev->GetMac()->GetShortAddress() << "\n"
                           // << "on device with address "<< bpd.dst<<"\n"
            //<< "was sent from address " << bpd.src << "\n"
            << "sequence number is " << (int) bpd.seq_nr << "\n"
            << "PAN ID is " << bpd.pan_id << "\n"
                            <<"with time "<< " on time: " << Simulator::Now ().GetSeconds() <<    "s"
            << "----------Packet received------------\n\n"

    );

Answer 1

The ns3::Packet::Print method is here to print the content of the packet:

https://www.nsnam.org/doxygen/classns3_1_1_packet.html#ad25486a838ac04533c83ff600d84546f

Now, you see zeros probably because the packet was initialized with a dummy payload made of bytes containing zeros. See:

https://www.nsnam.org/doxygen/classns3_1_1_packet.html#a897aab15901dcf1f05f075db7b8d04b1