Presentation Layer Definition

The presentation layer, the second layer from the top in the seven-layer OSI (open systems interconnect) model, translates data from programs and protocols in the application layer above it to formats that can be transmitted over networks and used by other applications on other hosts. It is likewise responsible for the delivery and formatting of information to the application layer for further processing or display.

Although the presentation layer is concerned with data structure representation, compression and encryption, these activities are sometimes performed at other layers, each offering its own advantages and disadvantages. Also, in many applications and protocols no distinction is made between the presentation and application layers.

Examples of presentation layer protocols include ASCII (American standard code for information interchange), EBCDIC (extended binary coded decimal interchange code), MIDI (musical instrument digital interface), MPEG (moving picture experts group), SSL (secure sockets layer), TDI (tabbed document interface), TLS (transport layer security) and XDR (external data representation).

Created November 6, 2005.
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