TCP/IP and the OSI Model – The Network (Internet) Layer

If you recall, the Internet layer’s primary responsibilities are determining a path between networks (routing), as well as network addressing. The addressing that takes place at the Internet layer is often referred to as logical addressing. These addresses aren’t “burned-in” like Ethernet MAC addresses, but instead are assigned by an administrator. The addressing protocol of the TCP/IP stack is the Internet Protocol (IP).

Note that TCP/IP routing protocols such as RIP, OSPF, and others also exist at the Internet layer. These will be looked at in Chapter 8, when routing is covered in detail.

Author: Dan DiNicolo

Dan DiNicolo is a freelance author, consultant, trainer, and the managing editor of He is the author of the CCNA Study Guide found on this site, as well as many books including the PC Magazine titles Windows XP Security Solutions and Windows Vista Security Solutions. Click here to contact Dan.