| TCP/IP stands for Transport Control
Protocol / Internet Protocol. It is a protocol suite used by most communications
software, especially in the U.S. It came out of the work on ARPANET (predecessor
to Internet). It is not so much of a model, but a base set of protocols.
Uses a connectionless network layer.
Ptocotols came first, where in
OSI reference model, the model came first. Model provides a nice basis
to talk about networks. TCP/IP provides better protocols for using them.
OSI is not widely accepted, especially
in the U.S. The major reason is that TCP/IP has been a fine working model
and most of the companies have invested heavily into TCP/IP. There are
some other criticisms. about the OSI model.
-
It would be nice if all layers were of roughly
equal size and complexity - in practice, the session layer and presentation
layer are absent from many existing architectures.
-
Some functions - addressing, flow control, retransmission
- are duplicated at each layer, resulting in degraded performance.
-
The initial specification of the OSI model ignored
the connectionless model, thus leaving much of the LANs behind.
-
The OSI model has too many layers the data has
to travel through, which will impact the performance.
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