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

Physical Addressing

As you learned in earlier chapters, the Network Access layer is necessary to relate the logical IP address, which is configured through the protocol software, with the actual permanent physical address of the network adapter. This physical address is often called the MAC address because, within the OSI model, physical addressing is the responsibility of the Media Access Control (MAC) sublayer. Because the physical addressing system is encapsulated within the Network Access layer, the address can take on a different form depending on the network architecture specification.

In the case of ethernet, the physical address is burned into the networking hardware at the factory. A few years ago, ethernet hardware almost always consisted ...