EFM frames on tagged port

[Mark]

Hello,

Reading the specs I didn't completely understand if EFM, CFM or LLDP frames
can be tagged or not. Specifically, what is the behavior of a L2 switch when
sending out such frames out a trunk port, i.e. the frames are supposed to be
tagged.

I understand that slow protocols use reserved destination multicast
addresses , i.e. 01:80:c2:x:x:x and by standard they are not supposed to
propagate the 802.1d bridge - so does this mean that bridge software *must*
treat such frames specially and do not tag/untag them at all?

Thanks

Mark