Presentation Layer of OSI Model
Presentation Layer of OSI Model in Computer Network
The presentation layer is layer 6 of the 7-layer Open Systems Interconnection (OSI) model. It is used to present data to the application layer (layer 7) in an accurate, well-defined and standardized format. It deals with the syntax and the semantics of the messages. The presentation layer is sometimes called the syntax layer.
The lowest layer of the OSI reference model is the physical layer. It is responsible for the actual physical connection between the devices. The physical layer contains information in the form of bits. It is responsible for transmitting individual bits from one node to the next. When receiving data, this layer will get the signal received and convert it into 0s and 1s and send them to the Data Link layer, which will put the frame back together.
Responsiblity of Presentation Layer
- Data encryption/decryption
- Character/string conversion
- Data compression
- Graphic handling
Functions of Presentation Layer
The main functions of the presentation layer are as follows
- It encodes the messages from the user dependent format to the common format and vice versa, for communication among dissimilar systems.
- It is responsible for data encryption and decryption of sensitive data before they are transmitted over common channels. It is also responsible for data compression. Data compression is done at the source to reduce the number of bits to be transmitted. It reduces the storage space and increases the file transfer rate. It is particularly useful for transmission of large multimedia files.
Design Issues with Presentation Layer
- To manage and maintain the Syntax and Semantics of the information transmitted.
- Encoding data in a standard agreed-upon way just like a string, double, date, etc.
- It Performs Standard Encoding scheme on the wire.