UDP Wirte shows no errors, but no data is transmitted

[goofylogic1998]

In my design I have three UDP ports, on a single NIC for specific types of messages, UDP Port 1 is used to establish connections between my application and another, UDP Port 2 is a command/response Port where commands are sent to me and I respond, and UDP Port 3 is a command/no-response port (i.e. I listen only on this port).  The process requires the establishment and closing of these connections multiple times over a period of time.  The issue I am running into is that after the first time through (connections establish, messages exchanged, connections closed with no errors), I can successfully (according to LabVIEW) open a connection on Port 1, I can successfully (according to LabVIEW) write data out on Port 1, but no data is actually transmitted over the wire.  LabVIEW is not producing any error codes.  The only way to make this work is to close and restart labview.  Any thoughts on what may be causing this problem?

[mikeporter]

Do the UDP examples that ship with LV work correctly? Can you post any code?

Mike...

[Mark_Yedinak]

First, show us your code. Secondly, there are no connections in UDP. It is basically a fire and forget protocol. Unlike TCP the open does not communicate with the destination machine. So it is possible to have a successful UDP open (you were able to create the UDP pipe on your end but the other side is not able to actually get the data. Your writes are successful because you did put the packet on the network. It obviously is not making it to the destination however this is a possible out come when using UDP. If you need to guarantee delivery of your data use TCP.