What main purpose does the OSI layer 2 serve in networking?

The main purpose of OSI layer 2, also known as the Data Link layer, is to perform framing and addressing for packets that require local delivery. This layer is responsible for converting the raw bits received from the physical layer into frames. It also attaches necessary control information to these frames, including hardware addresses (such as MAC addresses) that uniquely identify devices on a local network.

By framing the data, the Data Link layer ensures that the received bits are grouped correctly, allowing the network to interpret them accurately. This is crucial for facilitating the communication between devices on the same network segment, as it manages error detection and correction as well, which helps maintain the integrity of the data being transmitted.

While other functions such as routing between different networks, establishing sessions, or controlling how data is transmitted may occur at different layers of the OSI model, the specific function of framing and addressing packets for local delivery is exclusive to the Data Link layer. This distinction underscores the importance of this layer in enabling efficient, reliable local network communication.