For what two purposes does the Ethernet protocol use physical addresses?
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正确答案AE
