Wireshark-users: Re: [Wireshark-users] Question about frame.time_delta_displayed filter
From: Julian Fielding <jfielding@xxxxxxxxxxxxxxx>
Date: Thu, 5 Feb 2009 19:13:05 +0000

Frank Pall wrote on Thu, 5 Feb 2009 03:27:35 -0800 (PST):

> i am analyzing a huge amount of packets,and i am interested in the usage of the frame.time_delta_displayed filter,
> but i am honestly not understanding what's happening...

There's a clue in the name. The field  frame.time_delta_displayed depends on the previous frame that's displayed, which depends on the display filter. So it's not useful in a display filter because it changes its own data. It is useful in coloring rules and in menu Edit > Find Packet > by Display Filter.

Use frame.time_delta instead. That's the difference from the previous frame in the capture file.

> 2)i set the first sample as time reference

That's not relevant with frame.time_delta.

> PS:Just an additional off-topic question:is there some tool capable of building chart on captured packets?

Try Wireshark. Spend some time exploring the Statistics menu, see if anything there does what you want. If not, you could export to a spreadsheet. Wireshark and Tshark have several export options. I find Tshark -Tfields -ewhatever_field_you_want very useful:

"C:\Program Files\Wireshark\tshark" -rfilename.pcap -Tfields -eframe.number -eframe.time_delta -eip.src -ewhatever...>filename.txt
(That's on Windows, with typical installation.)

There are many other tools that might be useful. The libpcap file format is very popular. Try a search like "libpcap tools".

Julian.