To simplify usage, depending on the needs of users, IP addresses are divided into three classes.
Class A IP address given to the network with a very large number of hosts. IP Range 1.xxx.xxx.xxx. – 126.xxx.xxx.xxx, there were 16,777,214 (16 million) IP address in each class A. The IP address given for the class A network with a very large number of hosts. In class A IP address, network ID is the first 8 bits, while the host ID is 24 bits next. Thus, how to read a class A IP address, for example, 113.46.5.6 is:
Network ID = 113
Host ID = 46.5.6
So the above means the host IP address number 46.5.6 on the network number 113.
Class B IP address is usually allocated for medium to large sized networks. In class B IP address, network ID is 16 bits first, while the host ID is 16 bits next. Thus, how to read a class B IP address, for example 132.92.121.1
Network ID = 132.92
Host ID = 121.1
So the IP address above mean numbers 121.1 hosts on the network number 132.92. with a length of 16 bits of host ID, IP address networks with class B can accommodate about 65,000 hosts. IP Range 128.0.xxx.xxx – 191.155.xxx.xxx
Class C IP address originally used for small networks (LANs). Host ID is the last 8 bits. With this configuration, can be formed about 2 million networks with each network has 256 IP addresses. IP Range 192.0.0.xxx – 223.255.255.x. allocating an IP address is basically the process of selecting the network id and host ID that is right for a network. This exact configuration depends on the objectives to be achieved, namely to allocate IP addresses as efficiently as possible.