Presentation Layer of the OSI Model

Knoji reviews products and up-and-coming brands we think you'll love. In certain cases, we may receive a commission from brands mentioned in our guides. Learn more.
Presentation Layer of the OSI Model This is the sixth layer of the OSI model. This layer deals with syntax and semantics of the data exchanged between two devices. It transforms the data in the format that will be accepted by the application layer. Prese

Presentation Layer of the OSI Model

This is the sixth layer of the OSI model. This layer deals with syntax and semantics of the data exchanged between two devices. It transforms the data in the format that will be accepted by the application layer. Presentation layer receives data from application layer. It adds header to the data and passes data to the session layer. At the receiver side, the presentation layer receives data from session layer. It detaches header from the data and passes data to the application layer.

Responsibilities of presentation layer are:

Translation - The running programs on the computer exchange data in the form of character strings and numbers. Before transmitting, the information should be converted to bits format. The presentation layer handles interoperability between different encoding systems used by different computer systems. At the sending device, presentation layer changes the information from its sender-dependent format into a common format that will be accepted by the device. At the receiving side, presentation layer changes the information from the common format into its receiver-dependent format. For example, consider one device that uses Extended Binary Coded Decimal Interchange Code (EBCDIC) to represent data and wishes to transmit data to a device using American Standard Code for Information Interchange (ASCII) to represent the same data. The information sent directly won't be accepted by the device. To resolve this problem, the presentation layer performs the conversion of codes. At the sender's side the EBCDIC code is converted into a common format. At the receiver's end the presentation layer again converts that data (common format) into ASCII code.

Encryption - The presentation layer also adds security to data by encrypting it. Encryption is a process in which the data is converted into a form that prevents unauthorized users from reading. Encryption allows a system to carry sensitive and private information. The encrypted data is decrypted by the presentation layer at the receiving end. Decryption is a process opposite to encryption. It converts the encrypted message back to its original form.

Compression - Data compression refers to a process of encoding data using less number of bits. . This procedure reduces the number of bits used to symbolize the information. It is important while transmitting multimedia information such as text, audio and video. Lossless and lossy compressions are the two types of data compression techniques. In lossless compression, the data received after decompressing the compressed data is the exact replica of the original data. In lossy compression, the data received after decompressing the compressed data is not the exact replica of the original data. The data is lost in the compression and decompression processes. Presentation layer is responsible for performing data compression.

You may also be interested in understanding the other seven layers of the OSI Model

Application Layer of the OSI Model

Session Layer of the OSI Model

Transport layer of the OSI Model

Network Layer of the OSI Model

Data Link Layer of the OSI Model

Physical Layer of the OSI Model

0 comments