[Winpcap-users] winpcap 4.0.2 possible packet loss?

Tony Ballardie Tony.Ballardie at global-mix.com
Mon Oct 13 20:48:34 GMT 2008


Well the issue *may* be a red-herring. I was using a Microsoft Remote
Desktop connection and monitoring packet receive statistics in the
Windows media player. Apparently WM player stats viewed over RDP can be
misleading.

 

Although the problem seemed to manifest itself on Win Server 2003 and
Server 2008 Enterprise Edition, on both occasions the issue was only
seen over Remote Desktop connections. So far nobody was able to test it
on the respective consoles. The network card on both machines is a
Broadcom NetXtreme Gigabit Ethernet.

 

Today I ran the same app on my local XP PC and experienced zero packet
loss. 

 

So perhaps this wasn't an issue after all? I will continue testing on XP
and move onto other Microsoft platforms in due course, when the issue
*may* re-appear. Until then I'm parking the issue, unless someone knows
that it is a problem and can suggest a fix?

 

Thanks

 

Tony

 

Ps.which version of winpcap should I use on Vista? I downloaded 4.0.2
and installed it but the app that's using it "failed to initialize
pcap".

 

 

 

From: winpcap-users-bounces at winpcap.org
[mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Gianluca Varenni
Sent: 13 October 2008 21:20
To: winpcap-users at winpcap.org
Subject: Re: [Winpcap-users] winpcap 4.0.2 possible packet loss?

 

Do you have more details on the network card you are using (brand and
model)?

 

Have a nice day

GV

	----- Original Message ----- 

	From: Tony Ballardie <mailto:Tony.Ballardie at global-mix.com>  

	To: winpcap-users at winpcap.org 

	Sent: Friday, October 10, 2008 1:43 PM

	Subject: RE: [Winpcap-users] winpcap 4.0.2 possible packet loss?

	 

	Some more information on this issue...

	 

	The function 'pcap_sendpacket' is failing up to 40% of the time
when sending the streaming multicast packets to the kernel.

	 

	Is this a known issue, and is there a fix??

	 

	Tony

	 

	 

	From: winpcap-users-bounces at winpcap.org
[mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Tony Ballardie
	Sent: 10 October 2008 12:21
	To: winpcap-users at winpcap.org
	Subject: [Winpcap-users] winpcap 4.0.2 possible packet loss?

	 

	Hi,

	 

	Winpcap 4.0.2 is being used on a Windows Server 2008 box to
capture UDP-tunnelled streaming media (IP multicast) packets and then
present de-capsulated/original multicasts for playback in windows media
player on box. Depending on the stream, the bitrate may be 500-600kbps. 

	 

	The underlying multicast packets are being IP fragmented at
source, so each fragment is UDP-tunnelled so arrives as its own UDP
packet, becoming an IP fragment after tunnel decapsulation. 

	 

	I'm not the developer here but I'm presuming once the tunnelled
packets are decapsulated they are written back to NPF for subsequent
presentation to the IP layer and normal IP processing.

	 

	The on-box media player is showing up to 40% packet loss and
wonder if this could be due to the NPF not being capable somehow of
processing packets under these higher bitrate conditions? The path
between source and receiver is just a single-hop LAN and I'm confident
the packet loss is not happening in the network.

	 

	Or perhaps certain parameters need setting accordingly?

	 

	The network adapter is a Broadcom NetXtreme Gigabit Ethernet
adapter.

	 

	Any suggestions would be greatly appreciated.

	 

	Thanks

	 

	Tony

	 

	
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