Data Link Layer is the second layer in the OSI reference model. It represents creating a shared transmission medium and frequent transmission of the data frame in a computer transmission setting.
It can access a natural flow of elements for the physical layer at the sender device. The basic flow of data is generated using multiple technologies such as cable, DSL, wireless, optical fibre, etc.
The primary service of the data link layer is to support error-free transmission. The physical layer sends the data from the sender’s hub to the receiver’s hub as raw bits. The data link layer should recognize and correct some errors in the communicated data.
The data link layer provides a distinct connection to the network layer. It is used to handle communication bugs, control the data stream, and manage sender and receiver inconsistency by maintaining the multiple services. It can work these actions in the following method −
Unacknowledged connectionless service − This contains separate frames from the source host to the destination host without some acknowledgment structure. It does not have any link established or launched. It does not manage with frame recovery due to channel noise.
Acknowledged connectionless service − The transmission medium is more error-prone. This requires acceptance service for each frame shared between two hosts to provide that the frame has occurred correctly.
Acknowledged connection-oriented service − This layer supports this service to the network layer by settling a link between the source and destination hosts before any information removal occurs.
Framing − In this layer, it receives a raw bitstream from the physical layer that cannot be bug-free. The data link layer divides the bitstreams into frames to provide a frequent change of bitstreams to the network layer.
Error Control − It includes sequencing frames and sending control frames for acceptance. A noisy channel can avoid scanning of bits, falling bits from a frame, introducing specific bits in the frame, frames final sinking, etc.
Flow Control − There is another fundamental problem in the data link design to regulate the cost of data communication between two source and destination hosts. If the conflict among the source and destination hosts data sending and receiving speed, it will create packets to drop at the receiver end.
Sequence Integrity − The data link layer supports the data bits sequence and sends them to the physical layer in the similar sequence as received from the network layer. It supports a reliable share of data link service data unit (DLSDU) over the data link connections.