(also layer 6, syntax layer)
Presentation layer definition
The presentation layer is the sixth layer in the Open System Interconnection (OSI) model. It serves as the data translator for the network — it takes data formats from different sources and presents it to the application layer in an accurate, well-defined, and standardized manner.
Real presentation layer functions
- Data translation (conversion): The presentation layer is responsible for making sure that data is represented uniformly on all network devices even if they usually process and display data in different ways.
- Compression: Compression and decompression performed at the presentation layer can improve the throughput of data.
- Encryption and decryption: Some (but not all) encryption is done at the presentation layer to protect data as it travels down the protocol stack. A popular encryption scheme involving the presentation layer uses the Secure Sockets Layer (SSL) protocol.
- Serialization: Translating data structures and object states into formats that can be stored or transmitted. Serialization can be used to create clones of the original data in different computing environments.
Examples of presentation layer protocols
- AFP (Apple Filing Protocol)
- ICA (Independent Computing Architecture)
- LPP (Lightweight Presentation Protocol)
- NCP (NetWare Core Protocol)
- NDR (Network Data Representation)
- PAD (X.25 Packet Assembler/Disassembler Protocol)
- XDR (eXternal Data Representation)