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The OSI Model - Summary
The OSI (Open Systems Interconnect) Model is Application
the standard reference model used in networking 7
and communications. These are the seven Presentation
layers. This model is the basis for protocols that 6
are used when devices need to communicate Session
over a network. Every layer of the model has 5
protocols. The upper layers of the model are Transport
dependent upon the lower layers – for example, 4
the network layer (L3) depends upon both the Network
physical layer (L1) and the data link layer (L2) to 3
be operational. This is true of all the models
used in networking, including the TCP/IP model, 2 Data Link
which we’ll see shortly.
1 Physical
