OSI stands for Open System Interconnection. OSI model is a conceptual model which describes the communication between a computer system and a network. Moreover, there are seven layers in the OSI model which are categorized on the basis of different roles and functions. So, we have listed below all seven layers in the OSI model:
- Physical Layer
- Data Link Layer
- Network Layer
- Transport Layer
- Session Layer
- Presentation Layer
- Application Layer
1. Physical Layer
The physical layer in the OSI model comprises electrical and physical equipment involved in data communication. The physical layer includes different physical equipment like cables, switches, modems, and routers. Moreover, the physical layer is the end of OSI architecture in which data is converted into a bit stream for communication. It is responsible for data communication from one end to another in the network.
2. Data Link Layer
The data link is a layer OSI model which is responsible for error-free data communication between two directly connected nodes. The data link layer consists of two further sub-layers. The first layer of the data link is Media Access Control (MAC) which mainly controls the rights and permissions of data access. The second layer of the data link is Logical Link Control (LLC) which is responsible for error checking, rectification, and frame synchronization.
3. Network Layer
The network layer is the most critical layer of the OSI model. It is responsible for the transmission of data packets from one host to another. Moreover, the functions of the network layer include finding network devices with the help of IP and MAC addresses. Then it routes packets as per the destination address.
4. Transport Layer
The transport layer manages the transmission and the complete delivery of data packets which are further divided into segments. The transport layer ensures that data is transmitted in a sequence. Moreover, it also ensures data error rectification and prevents data duplication. The most common example of transport layers is Transmission Control Protocol (TCP) and User Diagram Protocol (UDP).
5. Session Layer
The session layer in the OSI model is the layer that opens and closes a session between two networking devices. Moreover, it Creates, Manages, Re-creates, and authenticates a network session for data communication. The session layer also ensures error control and data synchronization.
6. Presentation Layer
The presentation Layer also known as the Syntax Layer is mainly responsible for data translation., Secondly if computing devices are communicating over the encrypted connection then it also provides data encryption/decryption services. Finally, the presentation layer also facilitates data compression which helps in speedy and efficient data transfer.
7. Application Layer
The application layer is the layer in the OSI model that directly interacts with the end user for data communication. The end user can be a software application, for example, a browser or an email client. The application layer exposes protocols like HTTP, FTP, and SMTP that enable email and data communication.
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