Which address is used to identify devices on the same local network at the data link layer?

• A. Physical address
• B. Logical address
• C. Port number
• D. IP address

Answer: (A)

The data link layer identifies devices on the same local network using hardware addresses assigned to each network interface. In Ethernet, this is the MAC address, a unique physical address burned into the NIC. Frames carry both a source and destination MAC, and switches use these addresses to deliver frames within the same broadcast domain. While IP addresses identify devices across networks at the routing (network) layer, and port numbers identify specific processes at the transport layer, the MAC address is what precisely identifies a device on the local LAN. So, the address used at the data link layer to identify devices on the same local network is the physical address (MAC address).