Re: [WinPcap-users] Transmit Delay

[Gianluca Varenni]

Hi.   I think this is due to the receive process: Winpcap buffers packets in the kernel buffer, and then wakes up the application when either a timeout elapses (the one you set with pcap_open), or a minimum amount of data is present in the buffer (by default it's 16kB, you can change it with pcap_setmintocopy()), whatever comes first.   You can change such behavior by setting mintocopy to 0, but this can affect performance badly (since the application is waken up whenever a packet arrives, and this could led to a higher number of system calls, i.e. switches from kernel mode to user mode).   Hope it helps   Have a nice day GV ----- Original Message ----- From: Frank Natoli To: [EMAIL PROTECTED] Sent: Wednesday, June 16, 2004 11:56 PM Subject: [WinPcap-users] Transmit Delay Have two NIC machine, with Win32 GUI reading packets from each NIC using pcap_next_ex, then relaying those packets on the other NIC using pcap_sendpacket.   Can ping across this Winpcap facilitated connection, but see relatively long ping delays, anywhere between 500ms to 2000ms.   Cannot be certain whether delay is in receive or transmit. When sending a relayed packet, there is the abovementioned 500ms to 2000ms before the "echo" packet is received on the same NIC.   What might be causing this delay?