What is the main function of the Data Link Layer in the OSI model?

The main function of the Data Link Layer in the OSI model is to divide data into frames for transmission. This layer is responsible for ensuring reliable transfer of data across a physical network. It handles the packaging of raw bits from the Physical Layer into frames, which include not only the data itself but also control information, such as source and destination MAC addresses, error detection codes, and synchronization bits.

By framing the data, the Data Link Layer facilitates effective communication over the physical medium, managing errors that may occur during transmission and providing flow control to avoid overwhelming the receiving device. This framing is essential for differentiating between separate pieces of data, enabling multiple network devices to communicate without data collisions.

The other options, while related to different layers or functionalities, do not describe the primary role of the Data Link Layer. Establishing communication sessions pertains more to the Session Layer, while formatting data for the network and routing data packets are functions associated with the Transport and Network Layers, respectively.