Before the data is ready for transmission over the network channel, processing and converting the data with the specified services is necessary to reach proper transmission standards. This task is handled by the “Data-Link in the OSI Model.”
In this article on “Data-Link in the OSI model,” we will be briefed on the terms and information related to the working and functioning of the data-link layer.
What is the Data-Link Layer?
The “Data-Link layer,” is responsible for maintaining and terminating the established connection between the network devices over the network channel.
The Data-Link Layer has two sublayers:
- The first is the “medium access control,” which uses the MAC addresses from the network devices to transmit data between them.
- The second layer is the “logical link layer,” which identifies, checks flow control, and performs the error check for the transmitted data.
Working Of the Data-Link Layer
The data flow between the data-link layer and other layers in the OSI Model, i.e., to begin with, the network layer will share the data packets with the data-link layer.
The data-link layer handles these data packets by integrating them with the frame structure. The frame acts as a header for the data packet, containing information about the destination address, sender address, and other related services.
The final data format in the data-link layer is known as the data frame, which is then transmitted to the physical layer of the OSI Model.
Next, let’s look at the functions of the data-link layer in the OSI network model.
Functions of the Data-Link Layer
The working of the data-link layer in the OSI model requires the need functioning of the following attributes:
- The data packets received from the network layer are encapsulated in frames by the data-link layer for bit-to-bit sharing over the channel.
- It is also responsible for restructuring the framed data in the network model, and each data frame is different from the others.
- The task of adding a physical address to the frame in the header format is known as addressing.
- It acts as an identification service for transmitting the frames to multiple network models over the channel.
3. Flow Control
- During data transmission, the sender or receiver's data flow may differ, causing network traffic in the channel.
- The Data-link layer in such situations acts as a flow control for the sender side to prevent data overflow at the receiver side.
4. Access Control
- In this network model, when multiple devices share the same communication channel, this leads to data collision in the network channel.
- To prevent such data collision, the data-link layer performs checks on the devices with the same network channel to avoid data loss.
5. Error Control
- During data transmission, due to noise or signal loss, errors might occur in the data being transmitted.
- To minimize such data error rate, the data-link layer performs error detection and correction techniques on the transmitted data.
Sub-Layers of the Data-Link Layer
The data-link layer depending on the communication with the other OSI model is divided into two types of sub-layers:
1. Logical Link Control (LLC)
This is the upper sub-layer of the data-link layer.
- The LLC sub-layer is responsible for handling and maintaining the communication between the other layers of the OSI Model.
- It is also responsible for handling error messages and reliability checks for the data.
2. Media Access Control (MAC)
This is the lower sub-layer of the data-link layer.
- The MAC sub-layer is responsible for framing the data received from the upper layers.
- It also is responsible for data encapsulation and media access control for the data received.
With this, we have reached the end of this article on “Data Link Layer.” In case of any queries, do let us know in the comments section below.
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In this article on ‘Data-Link Layer in the OSI model,’ we learned the importance of applying the data-link layer for data encapsulation and integrating the frame header for the received data.
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