The network access layer, sometimes called the *data link layer*, deals with the creation of data packets and their transmission across a network. This layer corresponds to the physical hardware involved in network transmission. Hubs, modems, cables, and wiring are all considered part of this layer. The **address resolution protocol** (ARP) is part of the network access layer. ARP assists IP with directing data packets on the same physical network by mapping IP addresses to MAC addresses on the same physical network.