OCR GCSE Computer Science Complete Practice Exam 2025

The Data Link Layer is responsible for passing data over the physical network. It acts as an intermediary between the physical and network layers, ensuring that data is formatted properly for transmission over the specific type of physical network being used. This layer involves protocols that facilitate error detection and correction, as well as framing, which organizes the data into manageable units for transmission.

In the context of the OSI model, the Data Link Layer prepares data for the physical layer, ensuring that it adheres to the necessary protocols for the specific media (like Ethernet) being used. This includes the use of MAC addresses to identify devices on the same network segment.

Other layers have different responsibilities; for example, the Network Layer is focused on routing data packets between devices across different networks and managing logical addressing, while the Transport Layer is concerned with end-to-end communication, error recovery, and data flow control. The Application Layer, on the other hand, provides network services directly to user applications. Thus, the Data Link Layer is uniquely positioned to manage the transmission of data over the physical medium.