Unknown ethertypes 0x88e1 and 0x8912 from my Fritz Box

At least every 15 minutes, but sometimes more frequently, I receive two broadcast packets with ethertypes 0x88e1 and 0x8912 sent from the MAC address of my Fritz Box. I can't find these ethertype values on Wikipedia nor on LiveAction Ethertype Values list.

What protocol is that ? And where can I find a description of that protocol if not on Wikipedia ?

0x88e1 is HomePlug Management, for "Ethernet via powerline" bridges. The FritzBox might be looking to collect status information about the powerline network. (You can use open-plc-utils e.g. plctool or int6kstat to do the same from Linux.)

I'm not sure about 0x8912 but various posts say that it's also related to FritzBox's HomePlug functionality.

Related:

• https://pablo.tools/blog/computers/dropped-packets/
• https://serverfault.com/questions/1015896/linux-server-dropping-rx-packets-in-netif-receive-skb-core
• https://docbox.etsi.org/Reference/homeplug_av21/homeplug_av21_specification_final_public.pdf
• https://www.cise.ufl.edu/~nemo/plc/refs/HomePlug%20GP_Specification_Ch11_MMEs_v1.1-Jan_23_2012%20DRAFT.docx

The official list of ethertype values is found on http://standards-oui.ieee.org/ethertype/eth.txt.