What is the data link layer in Network Security?
In Network Security, the data link layer is the second layer from the bottom in the OSI model. The data link layer consists of the following sub-layers:
- MAC (Media Access Control)
- LLC (Logical Link Control)
What does the data link layer do?
The data link layer manages sets of bits for
The data link protocols include PPP, FDDI, Ethernet, and Token Ring.
Functions of the data link layer
Physical addressing
The data link layer represents the physical address of the sender or receiver if the frames are assigned to the various systems on the network. This is done by adding a header to the frame.
Half duplex
In half-duplex mode, data can be transmitted one node at a time.
Full duplex
During a full-duplex, data can be sent by both nodes at the same time.
Framing
The data link layer divides the data into bits, which are received via the network layer in the form of
Error detection
An error that is caused when noise during transmission or any other technical issue that would cause bits to flip is detected.
Error control and correction
The bits that are flipped due to errors are corrected and then flipped back to the original bits. The receiving node detects the error, and the data link layer also detects missing frames.
Flow control
Flow control prevents the receiver’s buffer from overflowing. The data link layer manages the speed of transmission of data at the ends.
Secure delivery
The data link layer transmits the data from the network layer without any errors.
Issues with the data link layer
Some of the issues of the data link layer are:
Data traffic regulation
It can be difficult to manage the transmission of data so that the slow receiver end is not overwhelmed by a fast sender end.
Errors
Transmitted data has the potential for errors.
Interface to the network layer
It provides an unacknowledged interface surface to the network layer by sending data from the network layer of the sending machine to the receiver machine’s network layer.