Laptop: GigE Vision + IMAQdx sometimes works, sometimes doesn't

[JKSH]

Hello,

I've developed an application for a customer that streams video from a GigE camera. It worked fine on our own development PCs.

It mostly works fine on the customer's laptop too. But every now and then, something causes the video stream seems to keel over and die.

Symptoms

• The image becomes very "stripey". Similar to the images below, but the horizontal black bands are much thicker.
• The same effect is seen directly in NI MAX, not just our custom software. 

Workaround

1. Unplug the network cable and plug it back in, and then
2. Refresh NI MAX -- the video becomes good again

Unfortunately, I can't reproduce the problem at will. The system works fine most of the time, and I haven't been able to identify what triggers the problem.

Any ideas on how I should start troubleshooting?

---

I wish I have better pictures, but I don't. The ones below are from an older (unrelated) test -- here, the black horizontal bands appeared when StreamBytesPerSecond was too high. Lowering StreamBytesPerSecond resolved that issue.

With my customer's laptop, however, the symptoms appear without any changes to the settings..

[b.ploetzeneder]

That's Ethernet package loss. 
Make sure your cabling is fine.

In MAX/ your camera configuration, turn down the desired peak bandwidth from 1k to 200, (that often solves the issue entirely). You can play with the other params, but that one is the most important. If you haven't, enable jumbo frames. Adjust packet sizes and increase resends. Make sure your network card is properly configured.

[JKSH]

Thanks for replying, b.ploetzeneder.

To clarify, I got rid of the issue shown in the screenshots already -- by reducing StreamBytesPerSecond from 115M to 10M. The screenshots were just an illustration to my other problem.

Most of the time, the video stream looks perfect. However, every now and then, I get effects much worse than the screenshots -- the ROI is 99% black, with a few coloured streaks. Disconnecting and reconnecting the network cable seems to resolve the problem (temporarily).

Do you think that's a packet loss issue too? I can understand it's packet loss if I get glitches now and then or if the bands are consistent. But does that explain the radical change from a glitch-free video stream to a 99% black stream?

The system is isolated -- not connected to a network.

(Anyway, thanks for your suggestion; I'll try reducing peak bandwidth when I get access to the system again)

[b.ploetzeneder]

Are you using a Intel Network Card?

[JKSH]

Yes, an Intel 82579LM.

I'll have access to the system later today. Will update this thread when I do.

[JKSH]

I found the Peak Bandwidth parameter and reduced it from 1000 to 200, as you suggested. Thanks.

Seems to be working well so far; we'll need to do load testing to verify that the problem has disappeared for good.

Do you know where I can find documentation about these parameters?

[b.ploetzeneder]

Unfortunately, not really. Most of what I know about these parameters has accumulated from troubleshooting over the years. The only thing I could find on the fly is this one: http://www.energie-und-technik.de/fileadmin/media/whitepaper/files/Leutron_wp_network-performance.pd...