Understanding MonitorSnifferTx trace

[Mihir Laghate]

Hi,

I am trying to obtain the transmit start time and duration of each packet in a simulated 802.11n network. I have two options: PCap output can be parsed through wireshark (slow?) or using the MonitorSnifferTx trace on the WifiPhy class to store only the time information I need. I anticipate the second method to be faster.

1. How do I get the time that the packet starts transmitting on the channel? I tried using Simulator::Now() but that does not match any of the time stamps in the corresponding PCAP file.

2. How do I compute the transmit duration of the packet? WifiPhy (and inheritors) have a ComputeTxDuration function that is used internally. But since the MonitorSnifferTx callback does not provide access to the Phy class. Am I correct in thinking that I would need to create a new struct to store a pointer to the Phy class and the function callback similar to that done in https://groups.google.com/forum/#!topic/ns-3-users/vlxGYuo7aBo ?

3. Finally, I am using the new Spectrum module because of its flexibility. Would that change how to approach these questions?

Thanks a lot!

- Mihir