What is the function of ARP in a network?

ARP, or Address Resolution Protocol, serves the essential function of mapping IP addresses to MAC addresses within a local network. When a device wants to communicate with another device on the same local network, it needs to know the MAC address that corresponds to the IP address of the target device. ARP facilitates this by broadcasting a request on the network asking, "Who has this IP address?" The device with that IP address responds with its MAC address. This process enables devices to send packets at the data link layer by using the appropriate MAC address, ensuring successful communication.

Understanding ARP's role highlights its importance in the networking model, particularly in the context of IPv4, where devices rely on this mapping for local area network (LAN) communications. Other options focus on different networking functions: managing traffic flow, filtering requests, and encrypting data are handled by other protocols and technologies, but they do not involve the core responsibility of ARP.