Me again!
I'm studying for my HCNA and I have found another use cases for it. And I can tell you that hybrid ports will be THE way to go in the future!
-------- Separate IPv4 and IPv6 traffic --------
You can use hybrid ports to separate IPv4 and IPv6 traffic into separate VLANs. How? Here it is:
You have to use a protocol based VLAN -> 4.7.1.5 Protocol-based VLAN Assignment. L2 frames carry an ETHERTYPE-tag. This in combination with a protocol-based VLAN assignment allows you to separate IPv4 and IPv6 traffic into VLANs.
E.g. you create a VLAN 14 for IPv4 and VLAN 16 for IPv6 traffic. In fact this is quite cool and absolutely the way to go in my opinion.
-------- Jumbo Frames --------
There is a proposal to tag JUMBO-Frames with a special Ethertype: 0x8870. You could detect jumbos automatically and let them run trough a special VLAN dedicated to this type of traffic, also with a protocol based VLAN assignment.
-------- Other use cases --------
There are other interesting Ethertypes: 0x88E5 MAC security (IEEE 802.1AE) ; 0x0806 Address Resolution Protocol (ARP) ; 0x8902 IEEE 802.1ag Connectivity Fault Management (CFM) Protocol / ITU-T Recommendation Y.1731 (OAM) so maybe there are other possibilities...
What do you think?