2.4. The OSI Model's Upper Layers
The upper layers of the OSI model deal with less esoteric concepts. Even though we're still discussing computer networking, the top three layers (Session, Presentation, and Application) seem easier to understand. Because the Network+ exam doesn't cover the upper layers (and many times these top three layers are grouped together), the following sections will give only a brief overview.
2.4.1. The Session Layer
Protocols that operate at the Session layer of the OSI model are responsible for establishing, maintaining, and breaking sessions, or dialogs. This is different from the connection services provided at the Transport layer because the Session layer operates at a higher level and looks at the bigger picture—the ...
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