DDS and Wireshark: A Deep Dive into the Newest Features
Written by Juanjo Martin Carrascosa
August 4, 2020
When I joined RTI a few years ago, we used to customize Wireshark® and provide our own installers to customers to help them analyze their network traffic. That customization contained improved dissection of DDS data transmitted over the RTPS protocol (but if you are a Wireshark user you already know this!). Wireshark is the best network protocol analyzer tool and is used all over the world, so having up-to-date support for DDS is key.
I quickly learned the hard way that the right way to improve the tool is to cooperate with the Wireshark community and provide our improvements to them directly. By working with the Wireshark community, they can code-review, approve and release updates to the whole world, not just RTI Connext DDS users. You can quickly see the benefit at wireshark.org; just download the latest version. It’s much easier than retrieving RTI’s customized version that may (or may not) be available for your operating system, or using a version that is not up to date with respect to other things like the GUI.
Long story short, it’s been almost 6 years since RTI started working directly with the Wireshark community. And now it’s time to share with you what’s new. Hint: it even includes new documentation to help you find what you need, quickly.
Dissection of your own data
Wireshark has done a great job of dissecting discovery data over the past few years, but we thought it might be time for Wireshark to tackle the user data too.
The first image (click to enlarge) shows user data. In this case, the features that dissect user data are disabled, so there is no information regarding the DDS Topic or DDS Type.
In this second image, you see that by simply enabling the “Topic Information” feature, Wireshark will map the DataWriter GUID with the Discovery Traffic, showing you what Topic and Type this sample belongs to. You will need the Discovery Traffic to be present in the capture for this feature to work.
And now Wireshark can even go one step further: Now it can understand TypeObjects. To use this, enable the “User Data Dissection” feature and take a look at your data sample:
If the Discovery Traffic is present and you are sending your types in Discovery, you will be able to see your samples dissected in Wireshark. No need for extra configuration, libraries or any other files. Isn’t this fantastic?
Keep in mind that the User Data Dissection uses the Topic Information feature, so you will have to keep both enabled if you want to analyze your user data.
We’ve been busy on more than updating the Wireshark DDS code. Our documentation now has a fresh look. We’ve also added best practices and useful filters so you can find information more quickly. Wireshark is an open source tool, but you can find RTI’s documentation about how to use Wireshark with DDS here.
Download the latest version
To get the latest improvements for Wireshark, download it from www.wireshark.org. Windows and Mac installers are provided. If you are working in a UNIX environment and want to use the latest version, you may need to build it yourself.
Learn More With RTI
Stay tuned! RTI updates the Wireshark tool and documentation as part of our regular release cycle. We have a team full of experts on DDS and Wireshark, and we want to make sure you learn how to use both efficiently.
To learn more about Wireshark and how to use it to debug problems in your DDS system, I invite you to join RTI in the September 24 Tech Talk: “Efficiency in Overdrive: How to Analyze DDS Traffic Using Wireshark”. We hope to see you there!
About the author:
Juanjo Martin is Services Director for RTI Professional Services. He joined the Engineering Department of RTI in 2012, where he started working in the support team and developed some features and improvements in several products, including Wireshark. Later, he joined the Professional Services team in order to help RTI customers optimize their systems. After traveling to help customers around the world for a few years, he now manages the EMEA and APAC Professional Services teams.