IP Address Classes Defined

IP Address Classes Defined

The IP address is 32 bits in length and is used to identify both the host address and the address of the network in which the host resides. An address class is defined to allocate the minimum number of bits that are to be used as the network ID. The remaining bits can be used to further subdivide the network using subnet masks and to define the host ID.

Table 3.4 illustrates the currently available IP address classes:

Class D addresses are used for Multicasting (for example Real Audio broadcasts across the Internet. Class E are experimental. Neither of these address classes can be used as a host ID.

Let’s revisit the one of the sample IP address shown in table 3.2. Based on our newly acquired knowledge of IP address classes, we see that IP address 207.21.32.12 is a Class C address. Note that the first octet is 207, and falls within the range of a Class C network. In addition, the binary equivalent of 207 is 1101111. Since the first three most significant bits are 110, we can again confirm that this is a Class C address.

Further Information