UDP Multicast Fails on NI Linux RIO Device with DHCP IP Address

Updated Jan 19, 2023

Reported In

Hardware

  • CompactRIO Controller

Software

  • LabVIEW Full
  • LabVIEW Base
  • LabVIEW Professional

Operating System

  • NI Linux Real-Time

Issue Details

I am able to send UDP packets from my cRIO to my host machine, but unable to receive UDP packets on my Linux cRIO. My cRIO is configured to obtain a DHCP IP address. What can I do to resolve this?
 

Solution

The behavior may occur if the net address of the is specified in the project's sender VI. To rectify this:
  1. Open the 'Sender VI' of the project. This will be the VI that has the UDP Multicast Open and UDP Write functions.
  2. Find the UDP Multicast Write-Only Open function. 
  3. Remove the input to the net address node.

Additional Information

The behavior comes from how Windows and Linux operating systems set up multicast sockets. Specifying the net address in the Sender VI should not be an issue if communicating receiving UDP information by a Windows machine.

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