In the OSI model, which layer adds Media Access Control (MAC) addresses to data packets?

In the OSI model, the Data Link Layer is responsible for adding Media Access Control (MAC) addresses to data packets. This layer serves as a vital link between the physical transmission of data and the network layer above it.

When a packet is prepared for transmission over a local area network (LAN), the Data Link Layer encapsulates the packet with a header that includes the MAC addresses of both the source device and the destination device. This addressing is essential for ensuring that data is correctly routed over a network segment since MAC addresses are used to identify devices on the same local network.

The Data Link Layer also provides error detection and correction, and it manages frame synchronization and flow control, which are critical for reliable communication. This layer ensures that the data packets are correctly formatted for the hardware technology that is being used for transmission, making the inclusion of MAC addresses one of its primary functions.

By understanding the responsibilities of the Data Link Layer, it becomes clear why this layer is associated with MAC addresses specifically, as it operates directly with the hardware and is essential for local data transmission.