The TCP/IP Protocol Suite
The TCP/IP protocol suite is a network model with four layers: Application, Transport, Internetwork, and Network Interface. These layers correspond to the layers in the OSI reference model.
A series of documents called RFCs define, describe, and standardize the implementation and configuration of the TCP/IP protocol suite. The InterNIC is responsible for maintaining these standards.
Notice in the next slide that the Application layer and the Network Interface layer of the TCP/IP model support multiple functions that require five different layers in the OSI reference model.