-------------------------------------------------- From: ""Fish" (David B. Trout)" <[email protected]> Sent: Wednesday, September 22, 2010 12:06 PM To: <[email protected]> Subject: Re: [Winpcap-users]Îòâåò: WinPCAP packets capture delay..
> Gianluca Varenni wrote: > > [...] >> As I wrote in the other mail, I don't have an explanation. That's >> why I would test the issue with different NIC boards and I would >> make sure that the transmitter is actually generating packets at >> a fixed rate (i.e. the transmitter is not introducing the delay). > > I believe he has already proven that. His oscilloscope verifies the > packets > ARE coming in at a steady rate. YET, despite that fact, the timestamps > would > seem to indicate that they are not. THAT is the problem! > > The two measurements (oscilloscope vs. WinPCap timestamp) conflict with > one > another. > > And I don't know about you, but as for me I would place my money on the > oscilloscope being right. :) Definitely true. The weird thing for me is using an oscilloscope to measure packet delays. I've never seen anyone using an oscilloscope for such measurement. I don't doubt the precision of the oscilloscope... Usually when people make this kind of measurement the use high end network analyzers and custom packet capture boards that timestamp packets in hardware... > > Hence the question: WHY are WinPCap's timestamps apparently wrong? What > would be causing it? > Or even better: why are packets delivered to WinPcap with such delay from the lower layers? Have a nice day GV > As for me, I don't know why! I can only offer conjecture/speculation (i.e. > guesses/ideas/possibilities/hypotheses) and let you and/or others falsify > them. > > I'm out of ideas! > > You? > > -- > "Fish" (David B. Trout) > [email protected] > > > > > _______________________________________________ > Winpcap-users mailing list > [email protected] > https://www.winpcap.org/mailman/listinfo/winpcap-users _______________________________________________ Winpcap-users mailing list [email protected] https://www.winpcap.org/mailman/listinfo/winpcap-users
