Forwarding Frame

[Webinar_Question]

How does a device know that the incoming PROFINET frame should be forwarded? Is it MAC address based?

[Alex.W]

How does a device know that the incoming PROFINET frame should be forwarded? Is it MAC address based?

Each Ethernet frame contains an address field that is used in Layer 2 (switching or bridging) to transmit the frames in a directed manner (point to point = unicast or point to multipoint = multicast/broadcast). This means that in the case of a unicast frame, only the network lines between sender and receiver see the frame where the frame is to be transmitted. All other nodes see nothing of the frame.

The address field in layer 2 contains the destination and the sender, both on a MAC address basis. The switches/bridges learn these MAC addresses and save them in the Forwarding Database (FDB).