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<DIV><FONT size=2>what I would probably do is use a hub between the two
machines, and try to capture the packets from a 3rd machine. I would then look
at the delay of all the packets, and try to understand where you lose
packets.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Also, what is the frame rate?</FONT></DIV>
<DIV><FONT size=2>I would also decrease the mintocopy value (pcap_setmintocopy)
to a couple of kB and see if that helps.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Have a nice day</FONT></DIV>
<DIV><FONT size=2>GV</FONT></DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=benpaka.spam@gmail.com
href="mailto:benpaka.spam@gmail.com">Benoit</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=winpcap-users@winpcap.org
href="mailto:winpcap-users@winpcap.org">winpcap-users@winpcap.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, October 19, 2008 5:43
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Winpcap-users] Slow receiving
speed (40Mbps), and packet loss.</DIV>
<DIV><BR></DIV>
<DIV dir=ltr>Hello,<BR><BR>I'm actually experimenting speed problem with the
winpcap 4.0.1<BR>library. I'm doing a software to control a Camera IP and to
receive<BR>frames from this one.<BR>The transmission protocol is done at the
MAC layer for the moment and<BR>is the following one:<BR><BR>1. PC_MAC
-> CAM_MAC: Ask for a frame.<BR>2. CAM_MAC -> PC_MAC : Send
a frame header packet (64 bytes).<BR>3. CAM_MAC -> PC_MAC : Send a
frame block packet (~1500 bytes).<BR> Repeat this operation 150
times until the whole image is<BR>transmitted, no ACK packet is used.<BR>4.
CAM_MAC -> PC_MAC : Send a "frame has been sent " packet (32
bytes)<BR>5. PC_MAC -> CAM_MAC : Send a ACK packet ("frame has
been<BR>received") packet (32 bytes), and go back to step 1.<BR><BR>Doing this
transmission protocol the speed is limited at 40Mbps which<BR>is very slow for
real time video stream.<BR>I've tried to play with the timeout
(pcap_open(...)) and with the size<BR>of the buffer (pcap_setbuff(...)) but
the results are quite similar.<BR>To capture the packet I'm using the
pcap_next_ex().<BR><BR>Finally If i do the same thing with two cameras: The
rate is still<BR>40Mbps but I'm loosing half of the packet. This mean for me
that the<BR>bottleneck is my program in C++, but I don't know how to solve
it...<BR>Maybe if someone has a good sample code with high speed
transmission<BR>(~Gbps) it could be helpful to understand where my application
failed.<BR><BR>Thanks for your help<BR><BR>--<BR>Benoit RAT<BR><A
href="http://www.neub.co.nr">www.neub.co.nr</A><BR><BR></DIV>
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