D-Link DES-3326 User Manual page 92

DES-3326 Layer 3 Fast Ethernet Switch User's Guide
Figure 5-10. OSI Seven Layer Network Model
Each layer is a distinct set of programs executing a distinct set of
protocols designed to accomplish some necessary tasks. They are
separated from the other layers within the same system or
network, but must communicate and interoperate. This requires
very well-defined and well-known methods for transferring
messages and data. This is accomplished through the protocol
stack.
Protocol layering as simply a tool for visualizing the organization of
the necessary software and hardware in a network. In this view,
Layer 2 represents switching and Layer 3 represents routing.
Protocol layering is actually a set of guidelines used in writing
programs and designing hardware that delegate network functions
and allow the layers to communicate. How these layers
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Switch Management and Operating Concepts