The physical layer manages hardware interfaces and determines the electrical and mechanical functions of the physical media, and this layer corresponds to the OSI physical layer. Phase IV DECnet Addressing DECnet addresses are not associated with the physical networks to which the nodes are connected. An area's value ranges from 1 to 63, inclusive. Likewise, a node address can be between 1 and 1,023, inclusive. Therefore, each area can have 1,023 nodes, and approximately 65,000 nodes can be addressed in a DECnet network.
Areas can span many routers, and a single cable can support many areas.
Figure 28-3 illustrates a sample DECnet network with several addressable entities. After this byte-swapped address is appended to the standard DECnet MAC address prefix, the address is AA00.0400.4B30. DECnet Phase V utilizes a layered approach that achieves a high degree of flexibility in terms of support for upper-layer protocol suites. As the following section discusses, DECnet OSI actually allows for the support of multiple protocol suites. This has contributed to the relatively wide acceptance of DECnet in the computer networking industry.