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.