RE: [WinPcap-users] Limitation with Transmitting frames using WinPcap

[Robert Thornthwaite]

Title: Message

Areg,   I am using Gigabit NICs.   I have not tried to see how many frames per second I can transmit.    I have more concerned with how many I can transmit as fast as possible in one burst and still receive all the frames on the other end.     I can generally transmit and receive 10,000 in 0.1 seconds.    Even it you are using 100Mb NICs 600 packets per second seems slow.    You can get high performance only if you are using the packetSendPackets() function in the Packet.dll or pcap_sendqueue_transmit() function in wpcap.dll which uses packetSendPackets().    This function uses only one call to the OS to send many packets.  The other method packetSendPacket() only sends one packet per call to the OS, unless you want to send the same packet many times, which it can do.     There is a bug somewhere in the handling of packetSendPackets() which causes it to occasionally corrupt packets.  This problem occurs when using gigabit NICs I do not know if it occurs with 100Mb NICs.    This is not a big problem for me since I am generating packets as part of testing an application that must be able to deal with corrupted packets.     Robert Thornthwaite Input/Output, Inc. -----Original Message----- From: Areg Alimian [mailto:[EMAIL PROTECTED] Sent: Sunday, August 10, 2003 10:13 PM To: [EMAIL PROTECTED] Subject: [WinPcap-users] Limitation with Transmitting frames using WinPcap I’m using npf.sys to send ethernet II frames out ethernet NIC.  I did some extensive measurements with the transmission rate and it appears that the maximum frame rate I can get with 64 byte frames is ~600 frames per second. Increasing the frame size to 1024 Bytes also allows my to send about 500+ frames per second.    Is this a limitation of the NPF driver?  If I increase the driver buffer size for queueing frames, would it affect the rates? The measurements were taken on a 1.6Mhz Laptop running Win2K with 500Mb of RAM.   Any input would be much appreciated.   -Areg Alimian