What is the function of the Address Resolution Protocol (ARP)?

The Address Resolution Protocol (ARP) plays a crucial role in facilitating communication over a network by mapping IP addresses to their corresponding Media Access Control (MAC) addresses. When a device wishes to communicate with another device on the same local area network (LAN) and knows the target's IP address, it utilizes ARP to discover the MAC address associated with that IP address. This is essential because while network communications often operate using IP addresses at a higher layer, the actual data frames transmitted over the physical network rely on MAC addresses for successful delivery.

When ARP is employed, it sends out a broadcast request for the MAC address corresponding to the desired IP address. The device with that IP address responds with its MAC address, which can then be used to encapsulate the IP packets within data frames for transmission. This process of resolving IP addresses to MAC addresses enables effective frame forwarding and ensures that data reaches the correct destination within the network.

Understanding the function of ARP is fundamental in networking, particularly in the context of Ethernet networks, where the interaction between IP and MAC addresses is critical for data exchange.