Networking

Network Link Selection

Ariel OS currently supports two different networking links: Ethernet-over-USB (aka CDC-NCM) and Wi-Fi. Boards may support both of them, only one of them, or none of them. However, currently the network stack supports at most one interface.

Which link layer is used for networking must be selected at compile time, through laze modules:

• usb-ethernet: Selects Ethernet-over-USB.
• wifi-cyw43: Selects Wi-Fi using the CYW43 chip along an RP2040 MCU (e.g., on the Raspberry Pi Pico W).
• wifi-esp: Selects Wi-Fi on an ESP32 MCU.

When available on the device, one of these module is always selected by default, currently preferring Wi-Fi networking. Overriding this default selection is possible by explicitly selecting the desired module.

Network Credentials

For Wi-Fi, the network credentials have to be supplied via environment variables:

CONFIG_WIFI_NETWORK=<ssid> CONFIG_WIFI_PASSWORD=<pwd> laze build ...

Using the Networking Link on the Device

Network Configuration

DHCPv4 is used by default for network configuration, including for IP address allocation. This is enabled by the network-config-dhcp laze module, selected by default.

In order to provide a static configuration, select the network-config-static laze module, which will take precedence. The configuration can be customized with the following environment variables:

Non-static IPv6 address allocation will be supported in the future.

Support for Network Protocols

Support for various network protocols can be enabled through Cargo features listed in the documentation. Most of these use embassy_net, which should be used through the ariel_os::reexports::embassy_net re-export.

Using the Network Stack

A network stack handle can then be obtained using ariel_os::net::network_stack().

See the examples for details.

Host Setup

Static IPv4 Address Configuration

When using a device with a static IPv4 address, the host computer can be configured as follows (where host_address is an IP address configured as gateway for the device):

# ip address add <host_address>/24 dev <interface>
# ip link set up dev <interface>

To verify that the address has indeed be added, you can use:

ip address show dev <interface>

Replace <interface> with the name of the used network interface. To find out the name of your interface you can use a command such as ip address.

Ethernet-over-USB

For Ethernet-over-USB, ensure that, in addition to the USB cable used for flashing and debugging, the user USB port is also connected to the host computer with a second cable.