What does ARP resolve to MAC addresses?

ARP, or Address Resolution Protocol, is specifically designed to map IP addresses to the MAC (Media Access Control) addresses of devices on a local network. When a device wants to communicate with another device on a network and only knows its IP address, it uses ARP to find out the corresponding MAC address. This is crucial because while devices communicate over a network using IP addresses, the actual data transfer occurs through MAC addresses at the Data Link layer.

In the ARP process, a device sends out an ARP request as a broadcast to the network asking, "Who has this IP address? Please send me your MAC address." The device that owns the specified IP address will respond with its MAC address. This ability to resolve IP addresses into MAC addresses facilitates the necessary communication at a low level, ensuring that data packets are correctly routed to the appropriate devices on the local network.