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Protocols implementing this layer: MIME, ASCII, Zip.
Professional working at this level: Application Developer, Network Application Team, Cryptographer,
Telecommunications Architect, Network Architect, Forensic Analyst, Network Engineer.
The presentation layer is primarily concerned with data conversion. Numerous standardization protocols are
used to ensure interoperability between systems and applications like ASCII and UNICODE. If conversion is
possible between two such standards, the presentation layer performs this function, but it also performs
compression, decompression, encryption, and decryption, although all such tasks are not exclusively part of
this layer.
Layer 7 — Application
Function: Various other applications generate and consume data at this level. This layer is the most diverse,
but also the most familiar to users. The applications that generate and modify user data implement the
application layer of the stack. It is a subtle difference, but this layer is not the applications themselves; rather,
it is the formatted data product of those applications.
Protocols implementing this layer: File Transfer Protocol (FTP), Hypertext Transfer Protocol (HTTP), Simple
Mail Transfer Protocol (SMTP), and many others.
Professional working at this level: Application Developer, Network Application Team, Cryptographer,
Telecommunications Architect, Network Architect, Forensic Analyst, Network Engineer.
The application layer and the presentation layer function together in most cases. Applications that organize
data into standard formats for interoperation use presentation layer file formats. Those formats are opened to
the user by applications with awareness of that file type. For example, most users automatically associate the
application, MS Word, with the file type “.docx.” These two layers have distinct functions, but differ from the
strictly data-in-motion layers: 2, 3, 4, and 5.

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