Sams Teach Yourself TCP/IP in 24 Hours, Fourth Edition

The Network Access Layer and the OSI Model

As Hour 2, “How TCP/IP Works,” mentioned, TCP/IP is officially independent of the seven-layer OSI networking model, but the OSI model is often used as a general framework for understanding protocol systems. OSI terminology and concepts are particularly common in discussions of the Network Access layer because the OSI model provides additional subdivisions to the broad category of network access. These subdivisions reveal a bit more about the inner workings of this layer.

As Figure 3.1 shows, the TCP/IP Network Access layer roughly corresponds to the OSI Physical and Data Link layers. The OSI Physical layer is responsible for turning the data frame into a stream of bits suitable for the transmission ...