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CycloneDDS Settings

CycloneDDS configuration

You can apply changes to the CycloneDDS configuration by creating a file at /etc/cyclonedds.xml (or any other path you prefer).

sudo nano /etc/cyclonedds.xml

Then you can set the CYCLONEDDS_URI environment variable to the path of the configuration file.

export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp
export CYCLONEDDS_URI=file:///etc/cyclonedds.xml/cyclonedds.xml

After the changes are applied, you need to restart the ROS daemon.

ros2 daemon stop

Alternatively, you can search the daemon process in htop and kill it.

$ htop

# press F3 to search, use keyword ros2cli.daemon
# trigger a kill signal with F9, then signal type 9

Traffic on the loopback interface

According to this issue, the ROS_LOCALHOST_ONLY environment variable is not supported in CycloneDDS and it should not be set in your ~/.bashrc file when you try to limit the traffic to the loopback interface.

You may achieve this by specifying the CycloneDDS to only listen to traffic from localhost.

This can be done by specifying the lo interface in the cyclonedds.xml file.

<Interfaces>
    <NetworkInterface name="lo" priority="default" multicast="default" />
</Interfaces>

You also need to enable multicast on the lo interface.

sudo ip link set lo multicast on

You can also persist the multicast setting on the lo interface by adding a systemd service.

sudo nano /etc/systemd/system/lo-multicast.service

[Unit]
Description=Enable Multicast on Loopback

[Service]
Type=oneshot
ExecStart=/usr/sbin/ip link set lo multicast on

[Install]
WantedBy=multi-user.target

System-wide network settings

You need to increase the maximum receive buffer size for network packets and set the IP fragmentation settings before you can apply the suggested CycloneDDS configuration.

sudo nano /etc/sysctl.d/10-cyclone-max.conf

Add the following content to the file.

# Increase the maximum receive buffer size for network packets
net.core.rmem_max=2147483647  # 2 GiB, default is 208 KiB

# IP fragmentation settings
net.ipv4.ipfrag_time=3  # in seconds, default is 30 s
net.ipv4.ipfrag_high_thresh=134217728  # 128 MiB, default is 256 KiB

Then you can apply the changes with the following command.

sudo sysctl -p --system

If you only want to apply the changes to the current session, you can use the following command

# Increase the maximum receive buffer size for network packets
sudo sysctl -w net.core.rmem_max=2147483647  # 2 GiB, default is 208 KiB

# IP fragmentation settings
sudo sysctl -w net.ipv4.ipfrag_time=3  # in seconds, default is 30 s
sudo sysctl -w net.ipv4.ipfrag_high_thresh=134217728  # 128 MiB, default is 256 KiB

You may validate the changes with the following command.

user@pc$ sysctl net.core.rmem_max net.ipv4.ipfrag_time net.ipv4.ipfrag_high_thresh
net.core.rmem_max = 2147483647
net.ipv4.ipfrag_time = 3
net.ipv4.ipfrag_high_thresh = 134217728

Suggested CycloneDDS configuration

The following is a configuration file that is suggested by the Autoare Network Settings documentation.

<?xml version="1.0" encoding="UTF-8" ?>
<CycloneDDS xmlns="https://cdds.io/config" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://cdds.io/config https://raw.githubusercontent.com/eclipse-cyclonedds/cyclonedds/master/etc/cyclonedds.xsd">
  <Domain Id="any">
    <General>
      <Interfaces>
        <NetworkInterface autodetermine="false" name="lo" priority="default" multicast="default" />
      </Interfaces>
      <AllowMulticast>default</AllowMulticast>
      <MaxMessageSize>65500B</MaxMessageSize>
    </General>
    <Internal>
      <SocketReceiveBufferSize min="10MB"/>
      <Watermarks>
        <WhcHigh>500kB</WhcHigh>
      </Watermarks>
    </Internal>
  </Domain>
</CycloneDDS>

Reference