⬆️ OSI Upper Layers 1.2.7

Layer 5 (Session Layer) Function

Administers the establishment, management (data transfer), and termination (tearing down) of a session or dialog between client and server.

Layer 6 (Presentation Layer) Function

Transforms data between the format required for the network and the format required for the application (e.g., character set conversion).

Example of Presentation Layer Transformation

Character set conversion between standards like ASCII and Unicode.

Other concepts supported by Layer 6

Data compression and encryption (though encryption is often implemented at lower layers or within Layer 7 protocols).

Layer 7 (Application Layer) Function

Provides an interface for software programs on network hosts to exchange data.

Layer 7 (Application Layer) Encapsulation Role

It is at the top of the stack and does not encapsulate any other protocols; it provides services to the software application.

Purpose of Upper-Layer Protocols

Provide the services that make a network useful (e.g., web browsing, email, directory lookup, and database services).