The presentation layer is the sixth layer (layer 6) of the seven-layer OSI model. The presentation layer is responsible for the delivery and formatting of information to the application layer for further processing or presentation to the user. It relieves the application layer from the responsibility in data representation.
This layer may translate data from a format used by the application layer into a common format at the source system. The presentation layer at the target system may re-translate the format into another appropriate format for its application layer.
The presentation layer provides the following services and functions. These functions ensure that information sent from the application layer of one system will be readable by the application layer of another system.
- Character code translation – i.e. ASCII to EBCDIC
- Data conversion and format – the use of standard image, sound, and video formats
- Data compression – de-duplicates the number of bits that need to be transmitted on the network
- Data encryption – encrypt data for security purposes
Some of the protocols that function at this layer include:
- Apple Filing Protocol (AFP)
- Independent Computing Architecture (ICA)
- Lightweight Presentation Protocol (LPP)
- NetWare Core Protocol (NCP)
- Network Data Representation (NDR)
- eXternal Data Representation (XDR)
- X.25 Packet Assembler/Disassembler Protocol (PAD)