What is the primary function of a MAC address in a network?

A MAC (Media Access Control) address is a unique identifier assigned to each network interface card (NIC) used in a local area network (LAN). It operates at the data link layer (Layer 2) of the OSI model and is used to uniquely identify devices on a network. This address helps in the local delivery of data packets within the same network segment by ensuring that the data is directed to the correct device. Unlike IP addresses, which are used for routing data between different networks and can change over time, MAC addresses are fixed and embedded in the hardware of the NIC. They are crucial for network communication and are used by network devices to identify and interact with each other on a local network.