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Finding a gap in length or id

asked 2019-06-11 22:27:13 +0000

LPF gravatar image

I am testing a LAN switch and I am sending packets with the length of each frame incremented by 1 from 126 to 1500 and back again. I am trying to use the incremented lengths to find a gap. All of these packets are coming from the same source, so if there is a way to find a gap in IP identifiers that would also solve my problem.

Thanks you!

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answered 2019-06-12 00:51:26 +0000

Bob Jones gravatar image

Maybe graph length of frames in the IO graph tool and look for a discontinuity? Do you know how to use it? Unless the gap is big, it might be easy to miss.

I would probably export the dataset and move to excel or another tool and have it calculate the length deltas for me... they should all be 1, except where a gap exists. So, graphing the delta calculation, anything above 1 would be a gap. It should stand out a little more this way.

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The I/O viewer isn't helpful because it is always bytes/sec, but exporting to excel works great!

Thanks Bob!

LPF gravatar imageLPF ( 2019-06-12 12:40:12 +0000 )edit

It's possible to get other values on the graph. If you are interested, we can provide more detail.

Bob Jones gravatar imageBob Jones ( 2019-06-16 20:02:09 +0000 )edit

answered 2019-06-16 18:52:24 +0000

updated 2019-06-16 18:53:08 +0000

You can do this task by different ways. 2 of them I show you.

  1. You can use tshark -> Have a detailed look here
  2. You can use the "File -> Export Packet dissections -> As CSV..." dialog to export the packet pane view to a csv file. After that you can import it into excel and do some sorts or scripting around it....
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Asked: 2019-06-11 22:27:13 +0000

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Last updated: yesterday