IP addresses are 32 bits long; like all network-level addresses, they have a network portion and a host portion. The network portion uniquely identifies the data link (that is, the network) and is common to all devices attached to the network. The host portion uniquely identifies a particular device attached to the network.
There are several ways to represent the 32 bits of an IP address. For instance, the 32-bit IP address
could be represented in decimal as
The binary format is cumbersome, and the decimal format is time-consuming to calculate. A better format is shown in Figure 2.9. The 32 bits of the address comprise four octets, each of which can be represented with a decimal number ...