Native Ethernet data link layer
Ethernet as a field network: PROFINET standard

The access method on Ethernet is called CSMA/CD (Carrier Sense Multiple Access/ Collision Detection). It's a contention technique that doesn't give exclusive access to the channel (like polling or tokenization), but tries to avoid conflicts and uses them as a method of channel allocation.

• CS (Carrier Sense): the ability to detect traffic on the channel (listen before speaking). If the station wishing to transmit notices that there is traffic on the network, it does not attempt to transmit, but waits until the channel is clear (figure 2 a ).

• MA (Multiple Access): each...