TCP/IP protocols are managed into five basic layers. Although some layers of the TCP/IP reference model related to layers of the ISO reference model, the ISO layers procedure does not have a layer that corresponds to TCP/IP Internet Layer.
TCP/IP reference model is given in the figure below.
Corresponds to physical network hardware layer in OSI.
Specifies how to manage data in frames.
Specifies the format of data packets transmit across an Internet and forwards data packets.
Specifies how to ensure reliable communication.
Like 6 and 7 in OSI architecture, it specifies how one application needs an Internet.
HOST COMPUTERS, ROUTERS AND PROTOCOL LAYERS:
TCP/IP describe the term host computer to refer to any computer machine that connects to an Internet and executes applications. A TCP/IP protocol makes it worth full for any pair of hosts to interact despite hardware differences.
Both routers and host require TCP/IP protocol software but routers do not require layer 5 protocols for applications, as they do not execute applications.