For what two purposes does the Ethernet protocol use physical addresses? (Choose two.)
A.
to uniquely identify devices at Layer 2
B.
to allow communication with devices on a different network
C.
to differentiate a Layer 2 frame from a Layer 3 packet
D.
to establish a priority system to determine which device gets to transmit first
E.
to allow communication between different devices on the same network
F.
to allow detection of a remote device when its physical address is unknown
Physical addresses or MAC addresses are used to identify devices at layer 2 -> A is correct.
MAC addresses are only used to communicate on the same network. To communicate on different network we have to use Layer 3 addresses (IP addresses) -> B is not correct; E is correct.
Layer 2 frame and Layer 3 packet can be recognized via headers. Layer 3 packet also contains physical address -> C is not correct.
On Ethernet, each frame has the same priority to transmit by default -> D is not correct.
All devices need a physical address to identify itself. If not, they can not communicate -> F is not correct.