Network stream read endpoint blocked by Win7?

[lmd2]

A little background first: I am using LabVIEW 2012 SP1 for dev. Ultimately there will be several admins authorized to configure a cRIO system remotely (from different computers in different parts of the world). I need to allow only one admin access at a time so I worked out a lockout approach using network streams to communicate to the cRIO and storing the active IP and a lockout Boolean. Okay so to prove out my approach I am modeling the code on three machines in my office, all on a local network. I am using 2 laptops running Win7 and an old desktop running WinXP. Here is my problem: when I create a network stream READ endpoint on the XP machine I can run a create network Write endpoint on either of the laptops and successfully send a command to the XP machine. However if the read endpoint is on either of the laptops, the connection is not established. The create Write endpoint hangs - doesn't matter if the write command is on the XP or Win7, if the read endpoint is on a Win7 machine the connection hangs. Sounds like a "permissions" issue(?)   Anyone out there dealt with this? maybe share a solution

   Thanks,  

lmd2

[Arham-H]

Hi Imd2,

I recommend running the network stream examples, that are shipped with LabVIEW, on the Windows XP and 7 computers. In NI Example Finder you can navigate to Networking»Network Streams and open Host VI.vi and Target VI.vi, one on each operating system. This approach will help in narrowing down the issue.

Regards 

[lmd2]

Thanks Arham

I sort of have confidence in my code, it is based on NI examples and does work 7 > XP. If I get the same results from the experiment that you suggest that is at least more data - then we can take it from there. I'll post a follow up in the morning, thanks for the reply and the suggestion.

- lmd2

[lmd2]

Morning Arham - if I run the host.vi on the Win7 machine, and the Target.vi on the XP machine everything works, both streams, the command in one direction and the data stream in the opposite direction. But when I reverse and run the Host on XP and the Target on Win7 nothing works, both VIs hang. So I am thinking it has to be the IP that gets entered in the host pointing to the target. I ran "ipconfig" from the command prompts (both machines) and and pinged each from the other - no problem (see attached screenshots). The only thing that I notice is that on the Win7 machine 'ipconfig' returns a few more parameters, like "Tunnel adapter isatap" and Tunnel adapter Teredo. Could it be that 192.168.1.6 is not sufficient for the connection? I am sure other people out there are running network streams with Win7 - any idea what might be going on here?

thanx

lmd2

[Whit-E_Wall-E]

Hello lmd2,

We were unable to reproduce the behavior you are experiencing when using Network Streams on Windows XP and Windows 7.  Even with a 192.169.1.6 IP Address both computers acted as a Host and Target as expected when using the Host VI and Target VI examples in LabVIEW.

Have you done any modifications to the example VIs?  What Windows XP OS are you using, Professional SP3 or something else?

Can the Windows XP run as both a Host and a Target on the same computer?

[lmd2]

The problem is not WInXP, if I take the desktop out of the equation and try using only the two Win7 laptops it still hangs (and yes I am using the examples unmodified). Win7 works as the host but never as the target whether the host is XP or Win7  - host doesn't matter, Win7 doesn't work as the target. This may not be a big problem since the real system (to be delivered to my client) will have cRIO as the target. I am just trying to understand this so that if things go south when I am deploying the final system I have some clue as to why. Maybe it is just some level of security that HP puts into their laptops, let's shelve this for now until I get the cRIO set up.

Thanks for your efforts

lmd2