During encapsulation at the data link layer for Ethernet, which address is added?

• A. The logical address is added.
• B. The physical address is added.
• C. The IP address is added.
• D. The process port number is added.

Answer: (B)

At the data link layer, Ethernet encapsulation adds a frame header that uses the device’s physical (MAC) addresses to deliver the frame on the local network. The Ethernet header includes the destination MAC address and the source MAC address, along with an EtherType field that indicates the next protocol in the stack. These MAC addresses are hardware identifiers tied to network interfaces, which is why they’re called physical addresses. IP addresses belong to the network layer and are carried inside the payload after encapsulation, not added at this layer. Port numbers belong to the transport layer (TCP/UDP) and are part of the transport header, not the Ethernet data-link header.