Using Packet_Sniffer_Project WinPcap example

[RLD]

I've been experimenting with the LabVIEW example program packet_sniffer which is based on WinPcap.  The application is to read "raw" (layer 2 type) Ethernet packets being transmitted from a proprietary circuit board to a dedicated NIC in the host computer.  The example VI's work great.  However, I notice a transitory effect that I don't understand.

The proceedure is to setup a test condition, read the data contained in the Ethernet packets then setup a new test condition and read the data and so on.  There is significant time between reads and the expectation is that a new read would return the most recent packets.  However, it appears that the packets are being buffered in a way the about a 1M byte worth of packets have to be pulled off before getting to the data from the new test condition.

Obviously this is not a LabVIEW problem, I was just wondering if anyone had any experiences that might shed some light on this.

[Bipin]

Hi RLD,

could you send me the link fo packet sniffer for downloading of the vi as i could not download the vi from the below link it seesm that they are not existing.

http://zone.ni.com/devzone/cda/epd/p/id/2660

Thanks in advance

[smercurio_fc]

Try the download again. I can confirm the link is just fine, and I was able to download the file. Perhaps your browser or your firewall is blocking the download?

[SimpiC]

Hi RLD,

I came across your post as I'm a network analyst recently converted to LabVIEW.  I'm sorry my reply is 6 years to late 🙂 .  The effects you observed are likely to be caused by the flow protocols that are embedded within TCP/IP (MTU, Windowing, Nagles Algorithm etc.).  When you say about 1Mb of data is transmitted between reads it may be that the maximum volume of data has been sent by the sender without recieving an acknowledgement.  If you've got the capture file (unlikely) then by all means send it across and I'd be happy to take a further look.

All the best.

SimonC

[erganesh]

Hi,

Can you send brief tutorial of Packet Sniffer project.

Thanks,

Ganesan

[Kilometers]

The link that Bipin posted contains a brief explanation on how the project works and what it's meant to do. Did you have a question about a specific part of it? Also, before we go any further I'd warn you that this application was developed for LabVIEW 8.0 and for an older version of WinPcap. There is no guarantee that it will work on newer systems.