Wireshark Analysis of DDS Packets

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Wireshark Analysis of DDS Packets

Hi,

I am trying to find the packets which been sent by the RTI DDS over the  network. I am capturing packets for Shape Demo with wireshark. I need help in the analysis part. I am attaching pcap file also with this topic.

I am trying to find the DATA which is been sent from publisher to the subscriber in the DATA Submessage, but i didn't find readable values of data (x, y, color etc) of the topic available in this sub message.

Can anyone help in figuring out that.

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Last seen: 4 months 3 weeks ago
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Hey,

First off:

Looking at your pcap I noticed mostly that you have a lot of discovery messages but not many 'possible' user data messages.

Have you verified that using rti dds ping works?

If so, have you tried using rti dds spy with -printSample option?

Going straight to wireshark is a bit extreme and you may want to use more user-friendly solutions before deep-diving that much.

If you are still keen on going for wireshark analysis:

while RTPS (and RTPS2) are well-known protocols supported for a very long time by wireshark other tools like it, your user data is not so 'easy' to understand.

Unlike JSON, which has a (fairly) descriptive nature (that is, field names and delimiters are sent in the object which is essentially a string), what RTI DDS uses is less "descriptive" on the wire (which allows it to achieve greater throughput of ACTUAL data).

This makes it harder for wireshark to deserialize your data.

There are ways used to dissect user data using wireshark.

The most common method is to use a LUA script which helps wireshark in understanding the structure of your user data. This method is used extensively and you may find many examples of how to use it online.

 

Good luck,

Roy.