Every company intending to be connected to the Internet must have an address plan first. It usually consists of two parts. The first is a schematic diagram of individual LAN to WAN connections, the other is a list of the individual LANs with estimated numbers of LAN interfaces. The address plan should include a reserve for potential expansion over the next two years. The reserve is usually double the present capacity. Then the address plan is sent to an Internet provider, implying a request for assigning a corresponding number of IP addresses.
Figure 6.8: A fictitious company network
An example: We are supposed to connect to the Internet a company using three local networks: Car Body Works, Paint Shop, and Engine Plant (a Regional Internet Registry never accepts a general application for the three A, B, and C networks—the concrete request must always be specified).
There are 8 computers in the Car Body Works, and the number is expected to increase to 16; the nine computers...