duplex

When a value is set, either "half" or "full", configures the device to use the specified duplex mode.

If "auto-negotiate" is "yes" the specified duplex mode will be the only one advertised during link negotiation: this works only for BASE-T 802.3 specifications and is useful for enforcing gigabits modes, as in these cases link negotiation is mandatory. If the value is unset (the default), the link configuration will be either skipped (if "auto-negotiate" is "no", the default) or will be auto-negotiated (if "auto-negotiate" is "yes") and the local device will advertise all the supported duplex modes. Must be set together with the "speed" property if specified. Before specifying a duplex mode be sure your device supports it.