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Wireshark-users: Re: [Wireshark-users] basic usage problem

From: Murilo Grizi <mbgrizi@xxxxxxxxx>
Date: Wed, 12 Dec 2012 15:31:21 -0200
Kurt,

I use Wireshark on Windows (ok, everyone kill me) and I've had this issue of 'packets missing' many times.

Possible causes that I identified were:
- Packet too big (had to enable Jumbo Frames on my NIC)
- NIC unable to read VLAN (had to create a VLAN tag on my board)
- Couldn't see VLAN tag on capture (had to even change the registry to do so... BTW: on Windows XP it worked, but changing the registry didn't do anything different on Windows 7).

I'm not sure that can help you, but, since you

2012/12/12 Bill Meier <wmeier@xxxxxxxxxxx>
On 12/12/2012 11:20 AM, Bill Meier wrote:
On 12/12/2012 9:59 AM, kurt.jensen@xxxxxxxxxxxxxxx wrote:
Just installed Wireshark and started capture. Plugged in our GigE camera
under development.  Connected and collected a frame of data.

Wireshark shows all of the GVCP requests and answers.  Very nice!  But I
am not seeing any of the UDP data.  I have no filters set, just selected
the interface then slicked start. I have run Wireshark before on another
computer where the UDP data just showed up along with the GVCP packets.
I know the data is there because my PC app displays the image. But not
in Wireshark.

How do I get the UDP data?

Kurt


I'm not sure I understand.

It appears that GVCP is carried over UDP so it sounds like you are
saying that only certain UDP frames are missing.

Is the "data" carried over the GVCP protocol ?

If so, I would expect the data show up as being under the GVCP layer of
the protocol tree (as opposed to the frames just showing as UDP.
IOW: the "protocol" column would show GVCP as opposed to UDP.

(I've no knowledge of the GVCP protocol so I may be off-base).


Update: It seems that there's a separate protocol (GVSP) for transferring data so ignore my comment above.

Is it possible that the data frames are being dissected incorrectly as another protocol by Wireshark (so that they don't show as UDP in the protocol column) ?






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