What is the main responsibility of the Data link layer in the OSI model?

The Data Link layer in the OSI model primarily focuses on facilitating the reliable transmission of data between directly connected nodes. One of its main functions is to break packets received from the Network layer into frames, which are then transmitted over the physical medium. This process involves adding headers and trailers to the data to create a frame that includes necessary control information, such as source and destination MAC addresses, error detection codes, and other data integrity measures.

By framing the data, the Data Link layer ensures that it can be properly interpreted by the receiving device and that it can handle any issues related to physical transmission, like errors that may occur during the sending of bits over the medium. This framing is crucial for effective communication within a local network or across point-to-point links.

Other functions of the Data Link layer, which include managing physical addressing and facilitating access to the shared medium (in the case of multiple devices), further underscore its foundational role in the process of data transmission.