I understand the concept of FCoE. I have looked at the Wikipedia page and looking at the layer 2 frame diagram, it looks like FCoE really should "just work" on any Ethernet switch, but is this really the case?

If so, what do switches like Cisco's Nexus 5k or 6120P offer that normal switches don't (in specific relation to FCoE)?

I am just using those two switches as examples. On the Nexus 5548UP page for example it says the following;

Unified ports that support traditional Ethernet, Fibre Channel (FC),and Fibre Channel over Ethernet (FCoE)

Well if FCoE runnins over regular Ethernet, that why does it support "Ethernet and Fibire Channel over Ethernet"?

This is why I am curious as to weather FCoE will run on any Ethernet switch and these switches just support "bonus" features, or if you do indeed require a specialist switch.

Thank you.