What does ARP stand for?

• A. Automatic Routing Protocol.
• B. Address Resolution Protocol mapping IP → MAC on a local network (L2).
• C. Address Reassignment Protocol.
• D. Anomaly Reporting Protocol.

Answer: (B)

Address Resolution Protocol is the mechanism that maps an IPv4 address to a MAC address on the local network. When a device needs to send a packet to another host on the same subnet, it uses ARP to find the destination’s hardware address. It broadcasts an ARP request asking who has that IP, and the host with the matching IP replies with its MAC address, allowing the requester to fill the Ethernet frame’s destination MAC. This ARP mapping is cached for quick reuse, so future communications don’t require another broadcast. If the destination is on a different network, ARP isn’t used for that hop—the router handles inter-network communication. The other options describe different kinds of protocols not involved in IP-to-MAC mapping.