Why Wireshark is not displaying RTPS sub-messages in the 'Info' column?

Question

I want to analyze the RTPS traffic in Wireshark.

I am running two applications that are transmitting and receiving a DDS (Data Distribution Service) topic in the same computer.

I can only see INFO_TS,DATA(p) in the info column and not the other sub-messages like HEARTBEAT, ACKNACK etc.,

Note: I tried using both shared memory and UDP4 protocol.

I have enabled RTPS dissection in the preferences Tab and expected to see RTPS sub-messages, but couldn't.

enter image description here

Answer 1

The submessages you mentioned should show up as illustrated in the Wireshark screenshot attached below.

Keep in mind that HEARTBEAT and ACKNACK submessages are only sent when doing reliable communications. Looking at the screenshot that you added, it only shows Participant discovery traffic. The associated submessages are marked as DATA(p). In order for reliable communications to happen, Endpoint discovery must have kicked in first. This means that DataWriters and DataReaders are discovering each other and start to exchange reliable communications, if configured to do so. Your capture does not show your system arriving at that stage.