The Data Link Layer is fifth layer in the Open Systems Interconnection (OSI) Model and is used for the encoding, decoding and logical organization of data bits. Data packets are framed and addressed by this layer, which has two sublayers.
The Data Link Layer's first sublayer is the media access control (MAC) layer. It is used for source and destination addresses. The MAC layer allows the data link layer to provide the best data transmission vehicle and manage data flow control.
The Data Link Layer's second sublayer is the logical link control. It manages error checking and data flow over a network.
Source: Data Link Layer