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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I’ve tried it on various PC network
interfaces, including a 10/100 USB network dongle and 2 different GigE PCI
motherboard-based interfaces. Different combinations of PCs and adapters result
in a different number of frames getting through, but the number is far less
than half in all cases.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>--<st1:place w:st="on">I.</st1:place> M.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><em><i><font size=3 color=navy face=Arial><span
style='font-size:12.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></i></em></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
winpcap-users-bounces@winpcap.org [mailto:winpcap-users-bounces@winpcap.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Gianluca Varenni<br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, April 16, 2010 1:13
PM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">winpcap-users@winpcap.org</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Winpcap-users]
losing transmitted packets</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face=Calibri><span style='font-size:12.0pt;
font-family:Calibri'>What kind of network card are you using on the transmitter
machine? can you reproduce it with different network cards?</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face=Calibri><span style='font-size:12.0pt;
font-family:Calibri'>GV</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma'><o:p> </o:p></span></font></p>
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<p class=MsoNormal style='background:whitesmoke'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> <a
href="mailto:Imre.Magyar@lairdtech.com" title="Imre.Magyar@lairdtech.com">Imre
Magyar</a> <o:p></o:p></span></font></p>
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<p class=MsoNormal style='background:whitesmoke'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>Sent:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Friday,
April 16, 2010 11:04 AM<o:p></o:p></span></font></p>
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<p class=MsoNormal style='background:whitesmoke'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>To:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> <a
href="mailto:winpcap-users@winpcap.org" title="winpcap-users@winpcap.org">winpcap-users@winpcap.org</a>
<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal style='background:whitesmoke'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>Subject:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
[Winpcap-users] losing transmitted packets<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hello all,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I have a win32 app that calls pcap_send() in a tight loop
repeatedly, on the same 1400 byte frame, say 1000 times.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The PC is wired directly to an embedded 10/100 network
device, but I do have a port aggregating tap device in between for monitoring.
There are no switches or hubs involved at all.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’ll run the win32 app, and see that only a small fraction
(say 500) of the frames are reported as received on the device at the other
end.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>If I run wireshark on the tap device, I see that the
receiving device reported the frame count accurately. Only 500 went out on the
link.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>If I run wireshark on the PC on the same interface the app
is sending the frames on, I see all 1000 frames.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>If I insert a small delay in the app between pcap_send()
calls (say I call Sleep(1) for a millisecond’s worth of delay), all 1000 frames
go out on the link, albeit much slower than I’d like.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Can anyone tell me what is dropping the frames and why? I’m
assuming I’m overrunning some internal transmit buffer somewhere, but I’m at a
loss to understand how to recognize it and when to back off. The pcap_send()
function never returns with an error.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks for any advice,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>--Imre M.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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face="Times New Roman"><span style='font-size:12.0pt'>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>_______________________________________________<br>
Winpcap-users mailing list<br>
Winpcap-users@winpcap.org<br>
https://www.winpcap.org/mailman/listinfo/winpcap-users<o:p></o:p></span></font></p>
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