OSI Reference Model Networking Layers, Sublayers and Layer
Groupings (Page 1 of 3) The most important OSI Reference Model
concept is that of networking layers. Its not an exaggeration to
say that layers are really the heart of the OSI modelthe entire
point of the model is to separate networking into distinct
functions that operate at different levels. Each layer is
responsible for performing a specific task or set of tasks, and
dealing with the layers above and below it. The rest of this
section will deal with many of the different nuances of this
layer orientation. The OSI Reference Model is comprised of seven
conceptual layers, each assigned a ranking number from one to
seven. The layer number represents the position of the layer in
the model as a whole, and indicates how close the layer is to
the actual hardware used to implement a network. The first and
lowest layer is the physical layer, which is where low-level
signaling and hardware are implemented. The seventh and highest
layer is the application laye