Figure 17-3 illustrates the calculation of costs in a DECnet Phase IV routing environment. Protocol Cost Calculation 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. 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 17-4 shows a sample DECnet network with several addressable entities. After this byte-swapped address is appended to the standard DECnet MAC address prefix, the resulting address is AA00.0400.4B30. Routing Levels DECnet routing nodes are referred to as either Level 1 or Level 2 routers. A Level 1 router communicates with end nodes and with other Level 1 routers in a particular area. Level 2 routers communicate with Level 1 routers in the same area and with Level 2 routers in different areas.