The Data Link Layer, designated as Layer 2 in the Open Systems Interconnection (OSI) reference model defined by ISO/IEC 7498-1, provides the functional and procedural means to transfer data between adjacent network entities and to detect and possibly correct errors that may occur in the Physical Layer.[1] This layer ensures node-to-node delivery of data within a local network segment by organizing bits into structured frames, managing access to the shared physical medium, and implementing mechanisms for flow control and reliable transit.[2]Key functions of the Data Link Layer include framing, where data packets from the upper Network Layer are encapsulated with headers and trailers containing synchronization bits and error-checking codes; physical addressing using Media Access Control (MAC) addresses to identify devices on the local network; and error detection and recovery through techniques such as cyclic redundancy checks (CRC) and acknowledgments.[3] In the IEEE 802 standards for local area networks (LANs), the Data Link Layer is subdivided into two sublayers: the Logical Link Control (LLC) sublayer, which provides a uniform interface to the Network Layer, handles multiplexing of protocols, and manages flow and error control; and the MAC sublayer, which deals with medium access, framing specific to the physical topology, and collision detection or avoidance in shared environments.[4]