The data link layer forms the second layer/Layer 2 in the OSI model, the standardized reference model for structuring network communication.
This layer is responsible for the secure and reliable transmission of data between directly neighboring network nodes. The main functions are the addressing of devices via the physical MAC address, the control of access to the transmission medium, error detection and correction as well as the segmentation and merging of data into frames. Protocols such as Ethernet or PPP (Point-to-Point Protocol) are used to access the medium.
The data link layer ensures that data is transmitted correctly between devices and that differences in the network are avoided. This layer therefore forms the basis for reliable data communication in the network.