fastdds.xml

<?xml version="1.0" encoding="UTF-8" ?>

<profiles xmlns="http://www.eprosima.com/XMLSchemas/fastRTPS_Profiles" >
    <transport_descriptors>
        <transport_descriptor>
            <transport_id>UdpTransport</transport_id>
            <type>UDPv4</type>
        </transport_descriptor>
    </transport_descriptors>

    <participant profile_name="udp_transport_profile" is_default_profile="true">
        <rtps>
            <userTransports>
                <transport_id>UdpTransport</transport_id>
            </userTransports>
            <!-- Disables shared memory; required for Isaac Sim ROS2 Extension to transmit topics, especially between Docker containers or over the network -->
             <!-- this is because if shared memory is enabled, ROS2 looks up message pointers thinking it's all on the same machine when it's not -->
            <!-- https://answers.ros.org/question/370595/ros2-foxy-nodes-cant-communicate-through-docker-container-border/ -->
            <!-- https://docs.omniverse.nvidia.com/isaacsim/latest/installation/install_ros.html#isaac-sim-app-install-ros:~:text=Run%20export%20FASTRTPS_DEFAULT_PROFILES_FILE%3D~/.ros/fastdds.xml%20in%20the%20terminals%20that%20will%20use%20ROS%202%20functions -->
            <useBuiltinTransports>false</useBuiltinTransports>
        </rtps>
    </participant>
</profiles>