Which EtherTypes are recognized for 802.1AD / QinQ ?

From: I.C.H <i.c.h_at_will-hier-weg.de>
Date: Fri, 13 May 2022 09:14:26 UTC
Hi all,

i allready asked the question in the FreeBSD Forums, but i was told to
better aks this question in the mailing list to be sure.

You can find my question and all the answers given in this topic here:

I will also quote the initial question at the end of this email.

Thanks for clarify my question.

Kind regards

Hi all,

802.1AD defines the EtherType / TPID as 0x88A8.
FreeBSD supports 802.1AD (QinQ tagging), see
<https://www.freebsd.org/cgi/man.cgi?ifconfig(8)> -> vlanproto

Before IEEE passed 802.1AD , there were proprietary standards for VLAN
stacking, often called 802.1QinQ or similar. Sometimes, vendors used
0x9100, 0x9200 or 0x9300 as EtherType for the "outer" tag, but some
switches can also insert 0x8100 into another 0x8100.

Today, its still possible to buy switches with QinQ-capability with
proprietary QinQ implementation which uses some non-802.1AD-compliant
EtherTypes. Not all offer the ability to change the EtherType to 0x88A8
or define it by your own, so you have to deal with it.

I am wondering, which EtherTypes are assigned internally in FreeBSD to
be handled as QinQ ?

I googled a bit and found this, but i am not sure if it will answer my
question: https://reviews.freebsd.org/D21846

Thanks for helping to clarify this topic.

Kind regards