Trusted answers to developer questions
Trusted Answers to Developer Questions

Related Tags

communitycreator
general

What is the data link layer in Network Security?

Arooj Fatima

Grokking Modern System Design Interview for Engineers & Managers

Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.

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)
The OSI Model

What does the data link layer do?

The data link layer manages sets of bits for transmission in the form of packetswhere the packets are transmitted from one end to the other. The data link layer is capable of managing packets using different protocols on different connections in a path.

The data link protocols include PPP, FDDI, Ethernet, and Token Ring.

Different Protocols on Different Links

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 blockscalled frames.

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.

RELATED TAGS

communitycreator
general

Grokking Modern System Design Interview for Engineers & Managers

Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.

Keep Exploring