Network Stream Error -314340 due to buffer size on the writer endpoint

[JCFox]

Hello everyone,

I just wanted to share a somewhat odd experience we had with the network stream VIs.  We found this problem in LV2014 but aren't aware if it is new or not.  I searched for a while on the network stream endpoint creation error -314340 and couldn't come up with any useful links to our problem.  The good news is that we have fixed our problem but I wanted to explain it a little more in case anyone else has a similar problem.

The specific network stream error -314340 should seemingly occur if you are attempting to connect to a network stream endpoint that is already connected to another endpoint or in which the URL points to a different endpoint than the one trying to connect. 

We ran into this issue on attempting to connect to a remote PXI chassis (PXIe-8135) running LabVIEW real-time from an HMI machine, both of which have three NICs and access different networks.  We have a class that wraps the network stream VIs and we have deployed this class across four machines (Windows and RT) to establish over 30 network streams between these machines.  The class can distinguish between messaging streams that handle clusters of control and status information and also data streams that contain a cluster with a timestamp and 24 I16s.  It was on the data network streams that we ran into the issue. 

The symptoms of the problem were that we if would attempt to use the HMI computer with a reader endpoint specifying the URL of the writer endpoint on the real-time PXI, the reader endpoint would return with an error of -314340, indicating the writer endpoint was pointing to a third location.  Leaving the URL blank on the writer endpoint blank and running in real-time interactive or startup VI made no difference.   However, the writer endpoint would return without error and eventually catch a remote endpoint destroyed.  To make things more interesting, if you specified the URL on the writer endpoint instead of the reader endpoint, the connection would be made as expected. 

Ultimately through experimenting with it, we found that the buffer size of the create writer endpoint  for the data stream was causing the problem and that we had fat fingered the constants for this buffer size.   Also, pre-allocating or allocating the buffer on the fly made no difference.  We imagine that it may be due to the fact we are using a complex data type with a cluster with an array inside of it and it can be difficult to allocate a buffer for this data type.  We guess that the issue may be that by the reader endpoint establishing the connection to a writer with a large buffer size specified, the writer endpoint ultimately times out somewhere in the handshaking routine that is hidden below the surface. 

I just wanted to post this so others would have a reference if they run into a similar situation and again for reference we found this in LV2014 but are not aware if it is a problem in earlier versions.

Thanks,

Curtiss

[Kelly_B]

Hi Curtiss!

Thank you for your post!  Would it be possible for you to add some steps that others can use to reproduce/resolve the issue?