Special Edition Using TCP/IP, Second Edition

The Link Layer

Before data can be sent over the physical medium, the software address that is used by the Internet layer to identify the hosts must be converted to a hardware address that can be recognized by the Network layer. Therefore, an address translation mechanism that translates addresses provided by the Network layer must be implemented. The Link layer, which acts as an interface between the Internet layer and the Network Interface layer performs this vital role (see Figure 2.3). It helps in bridging the gap between the different addressing formats that are used by both the layers. This task of resolving the software address to the corresponding hardware address is performed by a protocol called Address Resolution Protocol (ARP), ...