Can not exchange messages between two nodes running on different hosts Ubuntu/VxWorks

[mkrunic-windriver]

I have setup my environment according to instructions, but when I try ros2 multicast from both directions nothing is being received on the other side:

https://github.com/ros2/ros2cli/tree/master/ros2multicast

In the Wireshark the message is not detected. When I execute the following line on the VxWorks: [vxWorks *]# ifconfig gei0 inet add 224.0.0.1/8

message is then captured by Wireshark, but not with ros2 multicast receive.

Just to emphasize that I can ping other side from both directions.

Also I have added this line to vxscript: taskSpawn 0,50,0,0x20000,setenv,"RMW_IMPLEMENTATION","rmw_cyclonedds_cpp"

and: export RMW_IMPLEMENTATION="rmw_cyclonedds_cpp"

on Ubuntu, to be sure that I am using the same version of DDS.

I am using ROS2 Humble.

[razr]

Thanks for reporting it. Please do

Host side:

# add a multicast route to the tap0
$ sudo ip route add 225.0.0.0/8 dev tap0

$ sudo ip route show
...
192.168.200.0/24 dev tap0 proto kernel scope link src 192.168.200.254 
225.0.0.0/8 dev tap0 scope link

$ ros2 multicast receive
Waiting for UDP multicast datagram...

VxWorks side:

[vxWorks *]# python3 ros2 multicast send
Launching process 'python3' ...
Process 'python3' (process Id = 0xffff800000361780) launched.
Sending one UDP multicast datagram...

On the host side you should get

Received from 192.168.200.1:50614: 'Hello World!'

[mkrunic-windriver]

I can confirm that sending and receiving UDP packages using ros2 multicast is now successful.

Now the original problem still persists. I have created simple ros2 publisher subscriber packages. When I run publisher and subscriber on the same host (VxWorks or Ubuntu), subscriber successfully receives messages send by publisher, but when subscriber is run on a different host (VxWorks or Ubuntu), messages is not received.

As I have described above I have added this line to vxscript: taskSpawn 0,50,0,0x20000,setenv,"RMW_IMPLEMENTATION","rmw_cyclonedds_cpp"

and this to Ubuntu: export RMW_IMPLEMENTATION="rmw_cyclonedds_cpp"

just to be sure they are using the same dds middleware.

Is there anything else I have missed to configure to make these two nodes on different hosts to talk to each other?

[razr]

I'm still digging into the network setting problem.

[razr]

Starting from ROS 2 iron release the ROS_STATIC_PEER environment variable has been introduced. it works for the docker/host combination, see https://github.com/eProsima/Fast-DDS/discussions/3811. ROS_STATIC_PEER does not exist in humble, you need to use an XML profile instead. eProsima has recommended using this profile to communicate between two peers.

[borntocodeRaj]

So here are the steps On the docker side put the xml profile name it as fastdds-docker.xml in vxworks7-ros2-build repo

you can fill the file with the config as `<?xml version="1.0" encoding="UTF-8" ?>

172.17.0.1

7412 ` The IP address should be the IP address of the host. Export the file in docker export FASTRTPS_DEFAULT_PROFILES_FILE=/work/fastdds-docker.xml Docker should be launches as docker run -ti -h ros2native -v $PWD:/work vxros2build:humble wruser@ros2native:/work$ mkdir -p ros2_native/src && cd ros2_native wruser@ros2native:/work/ros2_native$ vcs import src < /work/build/ros2/ros2_ws/ros2.repos wruser@ros2native:/work/ros2_native$ colcon build --merge-install --cmake-force-configure --packages-up-to-regex examples_rcl* ros2action ros2component ros2node ros2pkg ros2service ros2topic ros2cli ros2lifecycle ros2multicast ros2param ros2run demo_* dummy_robot launch --cmake-args -DCMAKE_BUILD_TYPE:STRING=Debug -DBUILD_TESTING:BOOL=OFF wruser@ros2native:/work/ros2_native/install$ source setup.bash wruser@ros2native:/work/ros2_native/install$ ros2 run demo_nodes_py listener Keep this running in one terminal. In another terminal, run from the host. In the Host side, also keep the xml profile as `

172.17.0.1

7412 ` Keep the IP of the host, and then source the ros2 as source /opt/ros/humble/setup.bash source the path of the ros, then from the host also build the package as colcon build --merge-install --cmake-force-configure --packages-up-to-regex examples_rcl* ros2action ros2component ros2node ros2pkg ros2service ros2topic ros2cli ros2lifecycle ros2multicast ros2param ros2run demo_* dummy_robot launch --cmake-args -DCMAKE_BUILD_TYPE:STRING=Debug -DBUILD_TESTING:BOOL=OFF Once the build is successful. export the xml profile, by exporting the path in the host export FASTRTPS_DEFAULT_PROFILES_FILE=~/vxworks7-ros2-build/fastdds-docker.xml Now run on the host side ros2 run demo_nodes_cpp talker [INFO] [1692708772.697120937] [talker]: Publishing: 'Hello World: 1' [INFO] [1692708773.697069323] [talker]: Publishing: 'Hello World: 2' [INFO] [1692708774.697118381] [talker]: Publishing: 'Hello World: 3' You should observe wruser@ros2native:/work/ros2_native/install$ ros2 run demo_nodes_py listener [INFO] [1692708772.697120937] [talker]: Publishing: 'Hello World: 1' [INFO] [1692708773.697069323] [talker]: Publishing: 'Hello World: 2' [INFO] [1692708774.697118381] [talker]: Publishing: 'Hello World: 3' In case the connection breaks, try it again

[razr]

Hi @borntocodeRaj what is the difference between your setup and what I have described here

[borntocodeRaj]

Hello @razr (Andrei) the difference I see is the IP address for me in the xml profile is same for the docker and the host.

[razr]

I'm glad to see that it works on your side. Could you please put the content of both XML files you are using? I'm also wondering about this. You run listener, but the output messages are from the talker.

wruser@ros2native:/work/ros2_native/install$ ros2 run demo_nodes_py listener
[INFO] [1692708772.697120937] [talker]: Publishing: 'Hello World: 1'
[INFO] [1692708773.697069323] [talker]: Publishing: 'Hello World: 2'
[INFO] [1692708774.697118381] [talker]: Publishing: 'Hello World: 3'

[borntocodeRaj]

Hello @razr actually that is a typo, I am actually getting listener when I run listener, and talker on the side of the terminal, where I type talker, attached are the actual screenshot of that. Communication of talker and Listener

XML file content

[razr]

It looks like you have an error opening an XML file. Most probably you still run it with a non-peer-to-peer configuration. XML file shall be loaded on both sides

[razr]

The default gateway (g=192.168.200.254) was not set in the VxWorks boot line, Thanks @robwoolley for pointing it out.

[vxWorks *]# route show

INET route table - vr: 0, table: 254
Destination                     Gateway                       Flags    Use   If    Metric
0.0.0.0/0                       host                          UGS      0     gei0   0

[mkrunic-windriver]

I can confirm that the communication between VxWorks and Host (Ubuntu 22.04.) is working now on my side as well when adding default route. One more thing I had to do:

export RMW_IMPLEMENTATION=rmw_fastrtps_cpp

In my case rmw_cyclonedds_cpp was set as ros2 middleware, but default is rmw_fastrtps_cpp.

Thanks for support @razr and @rcwoolley!

Cheers, Momo