<div dir="ltr">Hi,<br><br>I'm using Windows XP Professional SP3 with Atheros AR8121/AR8113 PCI-E Ethernet Controller.<br><br>I'm following the statistics part of the tutorial: <a href="http://www.winpcap.org/docs/docs_40_2/html/group__wpcap__tut9.html">http://www.winpcap.org/docs/docs_40_2/html/group__wpcap__tut9.html</a><br>
<br>I'm sniffing the packets I'm sending and I'm sending a batch of Ethernet packets to my Ethernet device.<br>If I send N packets with size 60 or greater, I'm receiving all the N packets using the statistics mode.<br>
However, when I look at the "AcceptedBytes" field according to the winpcap tutorial, I'm receiving exactly 12 bytes more per packet sent.<br><br>Example: If I send 10 packets of 60 bytes, I receive in the statistics mode 10 packets and 720 bytes (instead of 600).<br>
Example: If I send 100 packets of 500 bytes, I receive in the statistics mode 100 packets and 51,200 bytes (instead of 50,000).<br><br>My guess is that it has something to do with the Ethernet Preamble / Start-of-Frame-Delimiter / Interframe gap fields of the Ethernet protocol since these fields are not part of the sniffed (or sent) packet.<br>
I'm not sure exactly why these 12 bytes are added to the statistics and would like to know for statistics analysis.<br><br>By the way, if I send packets with less than 60 bytes. The difference I receive per packet is 12 bytes + the number of bytes complementing to 60 bytes. This is obvious since the minimum Ethernet packet size is 60 bytes.<br>
<br>Example: If I send 100 packets of 25 bytes, I receive in the statistics mode 100 packets and 7,200 bytes (and not 2,500).<br><br>Thank you,<br><br>Boaz.<br></div>