Dotted-Decimal Notation

Dotted-Decimal Notation


To make Internet addresses easier for human users to read and write, IP addresses are

often expressed as four decimal numbers, each separated by a dot. This format is called

"dotted-decimal notation."

Dotted-decimal notation divides the 32-bit Internet address into four 8-bit (byte) fields

and specifies the value of each field independently as a decimal number with the fields

separated by dots. Figure 5 shows how a typical /16 (Class B) Internet address can be

expressed in dotted decimal notation.

Figure 5: Dotted-Decimal Notation

Table 1 displays the range of dotted-decimal values that can be assigned to each of the

three principle address classes. The "xxx" represents the host-number field of the

address which is assigned by the local network administrator.

Table 1: Dotted-Decimal Ranges for Each Address Class