CS601 GDB Solution

Because the Data Link Layer is Layer 2 of the seven-layer OSI model of computer networking. It corresponds to or is part of the link layer of the TCP/IP reference model. The Data Link Layer provides the functional and procedural means to transfer data between network entities and might provide the means to detect and possibly correct errors that may occur in the Physical Layer. The Data Link Layer is concerned with local delivery of frames between devices on the same LAN. Data Link frames, as these
protocol data units are called, do not cross the boundaries of a local network. Internet work routing and global addressing are higher layer functions, allowing Data Link protocols to focus on local delivery, addressing, and media arbitration. In this way, the Data Link layer is analogous to a neighborhood traffic cop; it endeavors to arbitrate between parties contending for access to a medium. The data link thus provides data transfer across the physical link. That transfer can be reliable or unreliable; many data link protocols do not have acknowledgments of successful frame reception and acceptance, and some data link protocols might not even have any form of checksum to check for transmission errors. In those cases, higher-level protocols must provide flow control, error checking, and acknowledgments and retransmission. The Data Link Layer protocols respond to service requests from the Network Layer and they perform their
function by issuing service requests to the Physical Layer. The Data Link Layer is often implemented in software as a "network card driver". The operating system will have a defined software interface between the data link and the network transport stack above.
This interface is not a layer itself, but rather a definition for interfacing between layers. The data link thus provides data transfer across the physical link. That transfer can be reliable or unreliable; many data link protocols do not have acknowledgments of successful frame reception and acceptance, and some data link protocols might not even have any form of checksum to check for transmission errors. In those cases, higher-level protocols must provide flow control, error checking, and acknowledgments and retransmission..