When it comes to 802.3az/EEE aka "Green Ethernet" there are basically two flavours on how to reduce the powerconsumption of a network device (specially when more than a few interfaces are being used):

• Powersaving of the PHY being used. Similar to how HLT-instructions are used on x86 CPU's to lower powerconsumption when there is nothing to do (or in the PHY case the time when there are no packets to be received or sent).

• For RJ45 interfaces adjust powerlevel to the detected cablelength. A TP-cable that is 2 meter in length will need less power to push the signaling through compared to a TP-cable that is say 80 meter in length.

Its not uncommon that these settings (EEE) nowadays are enabled by default.

However they are known to from time to time cause issues.

For example wired apple products are known to have issues with network switches/routers who does EEE where the workaround is to disable this for the particular interface. And there are other vendors/models where EEE needs to be disabled for them to function properly.

This can be manually done using ethtool (example below) but it would be handy if this could be part of set interfaces ethernet ethX aswell.

sudo ethtool --set-eee <NIC> eee off

It might also work to disable this system wide by adding this to the grub.cfg (kernel cmdline):

EEE=0

HPE Comware use this as command on interface-level to enable EEE (by default disabled):

port auto-power-down