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Version: ROS 2 Jazzy

Linux Network Configuration

Clearpath robots use netplan to configure all network connections, including wired and wireless interfaces. The netplan package is installed on Ubuntu by default.

To edit the netplan configuration files you will also need a text editor. The nano and vi editors are included by default, but additional editors such as vim or emacs can also be installed using the apt command.

Connecting to an Existing Wi-Fi Network​

Use netplan to connect your robot to an existing wireless network.

First, determine the name of your wireless interface by running iwconfig you should see an entry similar to this:

wlp59s0   IEEE 802.11  ESSID:off/any
          Mode:Managed  Access Point: Not-Associated   Tx-Power=off
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on

The interface name is in the left column, starting with w.

Once you have identified your interface, edit or create a file called /etc/netplan/60-wifi.yaml containing the following:

network:
  wifis:
    MY_WIFI_INTERFACE:
      optional: true
      access-points:
        MY_WIFI_SSID:
          password: MY_WIFI_PASSWORD
      dhcp4: true

with the following substitutions:

  1. Replace MY_WIFI_INTERFACE with the name of the interface you identified in the first step, e.g. wlp59s0
  2. Replace MY_WIFI_SSID with the SSID of your network.
  3. Replace MY_WIFI_PASSWORD with your network's password.

For example:

network:
  wifis:
    wlp59s0:
      optional: true
      access-points:
        BabCom:
          password: peekaboo
      dhcp4: true

This configuration will connect your robot via DHCP to your WPA2/3 wireless network. If you need to use a static IP address, modify the file to contain the following:

network:
  wifis:
    MY_WIFI_INTERFACE:
      optional: true
      access-points:
        MY_WIFI_SSID:
          password: MY_WIFI_PASSWORD
      dhcp4: false
      dhcp4-overrides:
        send-hostname: true
      addresses:
        - MY_STATIC_IP/MY_SUBNET
      nameservers:
        addresses:
          - MY_NAMESERVER

with the same substitutions noted earlier, plus

  1. Replace MY_STATIC_IP with the desired static IP address.
  2. Replace MY_SUBNET with the length of your network's subnet mask (typically 24 or 16)
  3. Replace MY_NAMESERVER with the IP address of your DNS server You may add multiple DNS servers with each one on its own line.

For example:

network:
  wifis:
    wlp59s0:
      optional: true
      access-points:
        BabCom:
          password: peekaboo
      dhcp4: false
      dhcp4-overrides:
        send-hostname: true
      addresses:
        - 10.25.0.134/16
      nameservers:
        addresses:
          - 10.25.0.10
          - 8.8.8.8
          - 8.8.4.4

Once you have edited the netplan configuration file, run the following two commands:

  1. sudo netplan --debug generate -- this will verify that the netplan configuration files can be read properly. Correct any errors before proceeding.
  2. sudo netplan try -- this will try running the new configuration, but will automatically roll back if it doesn't work correctly.
  3. sudo netplan apply -- this will apply the new configuration to your network interfaces.
note

By convention, all Netplan configuration files should be prefixed with two numbers indicating the order in which the file should be read. Files are read in alphanumeric order, with 00- prefixes first and 99- prefixes last.

If multiple files define the same configuration, the last-read file will override the earlier definitions.

Once all files have been processed the result is amalgamated to create the system's Netplan confguration.

Standard Clearpath Bridge​

The default networking configuration for a robot's computer is to bridge all Ethernet interfaces and assign the computer the IP address 192.168.131.1. See Reserved IP Addresses for a detailed list of IP ranges.

warning

Changing or removing the default bridge configuration may result in your robot no longer working properly. Certain components inside the robot rely on static IP addresses in the 192.168.131.0/24 subnet.

To configure the default bridge, create or edit /etc/netplan/50-clearpath-standard.yaml to contain the following:

network:
  version: 2
  renderer: networkd
  ethernets:
    bridge_enp:
      match:
        name: "enp*"
      dhcp4: false
      dhcp6: false
    bridge_enx:
      match:
        name: "enx*"
      dhcp4: false
      dhcp6: false
    bridge_eth:
      match:
        name: "eth*"
      dhcp4: false
      dhcp6: false
  bridges:
    br0:
      addresses:
      - "192.168.131.1/24"
      dhcp4: true
      dhcp6: false
      interfaces:
      - bridge_eth
      - bridge_enx
      - bridge_enp

This will bridge all physical ethernet ports together into the br0 bridge, which is assigned the static address 192.168.131.1. The bridge can also be used to connect to a wired DHCP server to provide internet access to the robot.

After editing the file, run the following commands to apply the changes:

  1. sudo netplan --debug generate -- this will verify your netplan configuration files and notify you if there are errors. Correct any errors before proceeding.
  2. sudo netplan try -- this will try running the new configuration, but will automatically roll back if it doesn't work correctly.
  3. sudo netplan apply -- this will apply the new configuration. Note that if you are logged in over SSH from a remote computer you may lose your SSH connection if the active interface was modified.

Determining the robot's IP address​

The robot's main computer can have several IP addresses for different connections. The robot will always have a static address on its internal network of 192.168.131.1 with a netmask of 255.255.255.0 (24 bits).

note

If your robot has a wireless base-station or long-range wireless radio integrated into it, these are considered part of the robot's internal network. When connected to the base-station you can log into the robot via its 192.168.131.1 IP address.

The robot's wired interface may also be connected to an external DHCP source to provide wired internet access, and the robot can be connected over Wi-Fi. To determine the robot's DHCP address, you must either

  1. Log into your router and look up the current DCHP assignments. This process will vary from vendor-to-vendor, so refer to your router's manual for instructions on how to do this.
  2. Log into the robot via its static 192.168.131.1 address and run the command ip a

Interpreting ip a output​

The ip a command produces a lot of output, and can be difficult to understand if you aren't familiar with it.

Sample Output

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host noprefixroute
       valid_lft forever preferred_lft forever
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br0 state UP group default qlen 1000
    link/ether 12:23:34:45:56:67 brd ff:ff:ff:ff:ff:ff
3: enp4s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br0 state UP group default qlen 1000
    link/ether 12:34:56:78:90:ab brd ff:ff:ff:ff:ff:ff
4: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff
    inet 192.168.131.1/24 brd 192.168.131.255 scope global br0
       valid_lft forever preferred_lft forever
    inet 10.0.100.42/16 metric 100 brd 10.0.255.255 scope global dynamic br0
       valid_lft 79814sec preferred_lft 79814sec
    inet6 1234::1234:5678:90ab:cdef/64 scope link
       valid_lft forever preferred_lft forever
5: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 70:1a:b8:2b:0b:b0 brd ff:ff:ff:ff:ff:ff
    inet 10.0.200.101/16 brd 10.0.255.255 scope global wlp2s0
       valid_lft forever preferred_lft forever
    inet6 1234::1122:3344:5566:7788/64 scope link
       valid_lft forever preferred_lft forever
6: vcan0: <NOARP,UP,LOWER_UP> mtu 16 qdisc pfifo_fast state UP group default qlen 100
    link/can
7: vcan1: <NOARP,UP,LOWER_UP> mtu 16 qdisc pfifo_fast state UP group default qlen 1000
    link/can

Note: MAC addresses have been redacted in the sample above

Each numbered item (1 to 7 in the example above) corresponds to a network interface. Each interface that has an active connection will have an entry of the form inet aaa.bbb.ccc.ddd/ee indicating its IP address. Some interfaces, such as the bridge interface described above, may have more than one address.

The items of note are:

  • br0: The Clearpath bridge interface. It will always have the inet 192.168.131.1/24 address, denoting its static address on the internal network. In this example it is also connected to a wireless DHCP source, giving it the address 10.0.100.42/16.
  • wlp2s0: the robot's wireless interface (the wireless interface will always start with w). In in this example the robot is connected to a wireless network with the address 10.0.200.101/16.
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