What type of mapping does ARP perform?

ARP, or Address Resolution Protocol, is specifically designed to map IP addresses to physical MAC (Media Access Control) addresses on a local network. When a device wants to communicate with another device on the same local network, it must first discover the MAC address associated with the destination IP address. The device sends an ARP request to the network, asking which device has the specific IP address, and the device that owns that IP address responds with its MAC address. This process is essential for enabling communication over Ethernet networks, where data packets are sent based on MAC addresses.

The other options presented do not accurately define the function of ARP. For example, ARP does not deal with mapping IP addresses to domain names (that function is handled by DNS - Domain Name System). Similarly, ARP is not involved in subnet masks or the relationship between MAC addresses and domain names. Thus, the correct choice distinctly highlights ARP's role in establishing the connection between IP addresses and their corresponding MAC addresses, underscoring the necessity of this mapping for network communications.