I understand that Profinet builds on Ethernet, but I am not quite sure how.
Ethernet has a lot of different standards for the physical layer, eg 10Base2 (coaxial, 10 Mbit/s), 100Base-TX (twisted pair, 100 Mbit/s) and 1000BASE‑SX (fiber, 1Gbit/s).
Let's say I have full access of a 10Base2 (coaxial) NIC, including writing a new driver for it if necessary, so that such NIC's can send frames back and forth, and the frames conform to PROFINET standard and the NIC's deal appropriately with Profinet frames. Can I call this Profinet?
If not, then what is the requirements for the physical layer in order to call the network Profinet? Perhaps the allowed physical layers are specified individually in the Profinet standard specifications? If so, where can I find a complete list of the physical layers that are part of Profinet?