IMAQdx timeout with JAI camera in multicast mode

[nathand]

We have a camera from JAI connected to a GigE card, displaying the image within a LabVIEW program, and this has run reliably for months.  We would now like to record the image for short periods of time as well.  We've added a second computer on the GigE network to capture and record the image stream with a dedicated piece of software.  We put the JAI camera into multicast mode so that both computers receive the same image.  Now, we get timeout errors in the LabVIEW program: error -1074360293 at IMAQdx Get Image.vi.  Increasing the timeout length to 10s (default is 5) didn't help.  Any idea why IMAQdx doesn't work in multicast, but works properly in unicast?  Is there some setting I've missed?

[ChristopheC]

Not all cameras support Multicast mode. If you get an error, try setting the Destination Mode attribute to Broadcast instead of Multicast.

-Christophe

[nathand]

The camera supports multicast mode, and it works for a while - anywhere from 5 minutes to an hour, from what the user is telling me.  Then it gets a timeout error and the acquisition stops.

[BlueCheese · Accepted solution]

Hi nathand,

It seems IMAQdx 3.9 added a bug that makes multicast mode not work properly (the camera is silently configured for unicast mode in certain cases -- internal CAR# 318906). Can you confirm if you are using this version or if you are using a previous version? If you are saying it works for a little bit of time but then fails I would assume it is _not_ this bug.

Do you know what type of switch you are using between the camera and the two PCs? If it is a managed switch it might be using IGMP snooping to determine which interfaces are listening to which multicast addresses. It is possible that a bug in the switch's implementation of this protocol might cause the association to drop after a while. You could possibly disable this snopping and either manually assign which multicast addresses are forwarded or have it forward to all ports.

Eric

[nathand]

Thanks for the suggestions.  We're running IMAQdx 3.5, and it's a Netgear GS105e switch.  I just upgraded the firmware on it and disabled IGMP snooping; I'll know in the morning whether this solved the problem, once the user has a chance to test it.

[nathand]

The user just reported to me that it's working properly with the IGMP snooping disabled - thanks!