[Winpcap-users] Winpcap and NIC chipsets

[Fulvio Risso]

Dear Stefano,
the behaviour you're observing is well-known. Sometimes it depends on 
the chipset, some other times it depends on the quality of the NIC drivers.
In either case, there's nothing you can do to bypass those issues in 
WinPcap.
The best solution is to replace the NIC.
Another possible solution is to use some accelerated NIC driver in order 
to bypass the Operating system, hence decreasing the overhead. However, 
again, those are usually able to operate only on a few NICs, and usually 
those are high quality NICs.
I'm not aware of those (free) drivers in Windows; probably something 
exist that does not come for free.
In Linux/FreeBSD you can use netmap, or pf_ring/DNA (linux only).

	fulvio


On 11/06/2013 08:57, Stefano Bonetti wrote:
> Hi all,
> we are using the Winpcap library inside a low-latency audio/visual
> streaming system named "LoLa"
> (http://www.conts.it/artistica/lola-project/lola-low-latency-audio-visual-streaming-system).
>
> More precisely we are using Winpcap to send about 55300 packet per
> second with the pcap_sendqueue_queue and pcap_sendqueue_transmit
> commands; each packet is 1000 bytes in size and the Lan speed is 1Gbit.
> The system performs very well (so thanks for you great job) but we have
> noticed a different behavior using
> some network adapters. With the Realtek or Marvell chipsets we are able
> to send/receive only half of the packets,
> but when we use Intel NICs we are able to send and receive all the
> packets (no drops and with the network monitor
> showing, correctly, 98% of utilization); for our project it means that
> we are sending/receiving a video stream at
> 60fps (uncompressed RGB, 24bit, 640x480).
> The Intel chipsets are 82574 and 82579 … we have tested many computers
> with the same result and the same
> behavior occurs even using the MS Winsock libraries, so it does not seem
> to be a problem related specifically to
> the winpcap library but generally to the NICs chipset.
>
> Has someone had similar experiences in the past or perhaps some
> suggestions on how to improve the network
> performance for Realtek/Marvell (or generally "low-cost") network chipset?
>
> Thanks in advance,
> Stefano Bonetti
> LoLa team developer
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