[Winpcap-users] WinPCap dropping packets UNLESS USB device
Jerry.Frame at disney.com
Thu Jan 20 12:45:11 PST 2011
Thanks Mark. I actually determined the issue today. It actually ended being a bios setting, but I'll elaborate a little just in case it helps anyone else.
In my original message, I had stated that Wireshark showed the broadcast was correct when ran on the local HP PC (IE, the one running the app that generates the broadcast.) What I discovered was that although Wireshark labeled the time between packets as ~100 MS, it was wrong. When I ran the local HP with Wireshark next to my laptop running Wireshark, the messages came in simultaneously (as expected), but while the local HP would say each packet was about 100 MS apart, my laptop showed them to be anywhere from 250 to 600 MS. When I insert a USB drive, the timing corrects itself, messages come in noticeably faster, and both PCs show 100 MS between packets.
A friend of mine ran into an article on some forum that mentioned how the timing of multi-core processors can get out of sync if the processors are configured to go into a low power mode if they are not being used. Sure enough, I went into the bios, disabled this, and it all worked as it should with no USB device plugged in. I'm not sure why plugging in a USB device fixed the issue, unless the act of plugging in a new device "woke" everything up.
From: winpcap-users-bounces at winpcap.org [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of winpcap-users-request at winpcap.org
Sent: Thursday, January 20, 2011 3:00 PM
To: winpcap-users at winpcap.org
Subject: Winpcap-users Digest, Vol 70, Issue 6
Send Winpcap-users mailing list submissions to
winpcap-users at winpcap.org
To subscribe or unsubscribe via the World Wide Web, visit
or, via email, send a message with subject or body 'help' to
winpcap-users-request at winpcap.org
You can reach the person managing the list at
winpcap-users-owner at winpcap.org
When replying, please edit your Subject line so it is more specific
than "Re: Contents of Winpcap-users digest..."
1. Re: WinPCap dropping packets UNLESS USB device pluggedin?
(Mark Pizzolato - WinPCap-Users)
Date: Thu, 20 Jan 2011 09:01:36 -0800
From: "Mark Pizzolato - WinPCap-Users"
<winpcap-users-20040408 at subscriptions.pizzolato.net>
To: <winpcap-users at winpcap.org>
Subject: Re: [Winpcap-users] WinPCap dropping packets UNLESS USB
<78FD0775812F9E429FF9F5E1AA158DBE4099CE at redroof.alohasunset.com>
Content-Type: text/plain; charset="us-ascii"
Just a shot in the dark here, but a possible one....
Compile and run the below program. See if you get the correct 10hz
behavior while that program is running...
- Mark Pizzolato
Link this with Winmm.lib
main(int argc, char **argv)
while (1) Sleep(1000000);
From: winpcap-users-bounces at winpcap.org
[mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Frame, Jerry
Sent: Thursday, January 20, 2011 5:51 AM
To: winpcap-users at winpcap.org
Subject: [Winpcap-users] WinPCap dropping packets UNLESS USB device
I've ran into a very odd situation with WinPCap 4.1.2. I have a several
quad core HP computers running a WinPCap based application that sends a
broadcast UDP message at 10hz. For some reason on these HP machines,
instead of the broadcast (192.168.x.255) coming out of the NIC at 10hz,
the traffic only seems to be at 1-3hz (this is displayed on our embedded
system.) If I run Wireshark on the local HP PC though, I clearly see a
packet every 100 ms. However, if I run Wireshark on another PC
connected to the same network, it confirms the 1-3 hz issue. Here's the
really strange thing. If I plug in a USB drive, or a USB network
adapter (even though I'm not using it), the broadcast starts working
normally (10 hz). Unplug the USB device, and it drops back down. I ran
a test application that uses basic Winsock (the Delphi Indy components
to be exact), and it always seems to work fine.
Any suggestions are greatly appreciated.
-------------- next part --------------
An HTML attachment was scrubbed...
Winpcap-users mailing list
Winpcap-users at winpcap.org
End of Winpcap-users Digest, Vol 70, Issue 6
More information about the Winpcap-users