What identifier is used at the data link layer to uniquely identify an Ethernet device?
- IP address
- MAC address
- sequence number
- TCP port number
- UDP port number
Explanation: Ethernet frames are identified at the data link layer by their MAC addresses, which are unique to each NIC. IP addresses are used at the network layer, and TCP and UDP port numbers are used at the transport layer. Sequence numbers are fields in TCP headers.
More Questions: CCNA 1 Module 6 Quiz – Data Link Layer Answers