Presentation layer

In the seven-layer OSI model of computer networking, the presentation layer is layer 6 and serves as the data translator for the network. It is sometimes called the syntax layer. Within the service layering semantics of the OSI network architecture, the presentation layer responds to service requests from the application layer and issues service requests to the session layer through a unique presentation service access point (PSAP).cite book | last = Hura | first = Gurdeep | title = Data and Computer of one system sends out is readable by the application layer of another system. On the sending system it is responsible for conversion to standard, transmittable formats. On the receiving presentation layer might be able to translate between multiple data formats using a common format. In many widely used applications and protocols no distinction is actually made between the presentation and application layers. For example, HyperText Transfer Protocol (HTTP), generally regarded as an application-layer protocol, has presentation-layer aspects such as the ability to identify character encoding for proper conversion, which is then done in the application layer. The presentation layer is the lowest layer at which application programmers consider data structure and presentation, instead of simply sending data in the form of datagrams or packets between hosts. This layer deals with issues of string representation - whether they use the Pascal method (an integer length field followed by the specified amount of bytes) or complex data structures into flat byte-strings (using mechanisms such as TLV, XML or JSON) can be thought of as the mally standardized at this level, often by using XML Data conversion Character code translation Compression Encryption and Decryption Serialization Protocols sometimes considered at this level (though perhaps not strictly adhering to the OSI model) include: Apple Filing Protocol (AFP) Independent Computing Architecture (ICA), the Citrix system core protocol Lightweight Presentation Protocol (LPP) NetWare Core Protocol (NCP) Network Data Representation (NDR) Tox, The Tox protocol is sometimes regarded as part of both the presentation and application layer eXternal Data Representation (XDR) X.