Each device on a subnet has which identifier that associates it with the others on the same subnet?

• A. IP Address
• B. MAC Address
• C. DNS Name
• D. Port Number

Answer: (A)

The IP address is the identifier that associates devices on the same subnet. It provides a logical address for each host within the network, and the subnet mask defines which part of that address identifies the network vs. the individual host. This allows devices on the same subnet to determine whether a destination is local (on the same subnet) or must be reached through a router. On the local link, ARP translates the IP address to a MAC address to deliver frames. The MAC address is tied to hardware and isn’t what groups devices by subnet; DNS names are human-friendly aliases resolved to IPs, and port numbers identify applications on a host, not network membership.