Illustrated TCP/IP by Matthew G. Naugle Wiley Computer Publishing, John Wiley & Sons, Inc. ISBN: 0471196568   Pub Date: 11/01/98

Chapter 18
TCP/IP: The Protocols (covered in this book) and the OSI Model

The best way to introduce TCP/IP is by looking at it through the ISO OSI model. I am not going to discuss the OSI model and its layer functions here. I am placing the protocol of TCP/IP into this model to show you where the protocol suite sits in this model.

Let’s start with understanding the functions and protocols by studying their placement in the OSI model. This slide shows that the protocol suite of TCP/IP has its place in the OSI model. The heart of the TCP/IP network protocol is at layers 3 and 4. The applications for this protocol (file transfer, mail, and terminal emulation) run at the session through the application layer.

As you can see, this protocol runs independently of the data–link and physical layer. At these layers, the TCP/IP protocol can run on Ethernet, Token Ring, FDDI, serial lines, X.25, and so forth. It has been adapted to run over any LAN or WAN protocol. TCP/IP was first used to interconnect computer systems through synchronous lines and not high–speed local area networks. Today, it is used on any type of media. This includes serial lines (asynchronous and synchronous) and high–speed networks such as FDDI, Ethernet, Token Ring, and Asynchronous Transfer Mode (ATM).

TCP/IP: The Protocols (covered in this book) and the OSI Model