Hi All,<br><br><br>I'm now working on a project which needs to to record the captured wireless packets arrival time precisely. I used Wireshark and CACE adapter before. But it seems they record the arrival time in microseconds. As Wireshark doesn't access the hardware directly, it receives the raw data from WinPcap, so I'm thinking maybe I can get more accurate local timestamp from winPcap directly<br>
<br>In the document of Winpcap, the NPF records the captured packets, and also their timestamps. I have several question and looking for help:<br><br>1. Where does the NPF get the time information to timestamp these incoming packet? The time information comes from a onboard timer in the adapter or from a CPU or similar computer clock?<br>
<br>2. Which function in the NPF or Packet.dll can be used as a trigger to request CPU timer, like queryperformancecounter (), to timestamp the arrival packet to obatin higher precision?<br><br>3. Is there any performance difference if I request the triger function through wpcap.dll and packet.dll?<br>
<br>4. Can I reduce the size of the user buffer inside the NPF to set it small enough to triger the CPU timer to timestamp when every packet is arrival?<br><br>Thanks for all your help.<br><br>Cheers<br><br>John<br>