What is the purpose of the address resolution protocol (ARP)?

The address resolution protocol (ARP) is primarily used for mapping an IP address to a physical MAC address within a local area network. When a device needs to communicate with another device on the same network, it must establish the appropriate link layer addressing to send data frames. ARP facilitates this process by allowing a device to broadcast a request for the MAC address associated with a specific IP address. Once the device that holds the requested IP address responds with its MAC address, the requesting device can then encapsulate its data in frames that can be sent over the local network using the correct MAC address.

This mechanism is essential for ensuring that data packets reach their intended destinations at the data link layer, as physical addresses are required for proper data transfer on the network. Understanding this mapping is crucial for network communication and operations, making ARP a fundamental protocol in networking.