IP addresses are classified into five types based on network ids: Class A, Class B, Class C, Class D, and Class E.
1. Class A IP address
In A Class A IP address, the first segment of the IP address is the network number, and the remaining three segments are the numbers of the local computer. In Class A IP addresses, the length of the network ID is 8 bits and the length of the host ID is 24 bits. Class A network addresses are small in number. There are 126 networks, each of which can accommodate more than 16 million hosts.
Class A IP addresses range from 1.0.0.1 to 127.255.255.254.
2. Class B IP addresses
In a Class B IP address, the first two numbers in the four segments of an IP address are network numbers. Class B IP addresses contain 16 bits of network ID and 16 bits of host ID. Class B network addresses are applicable to medium-scale networks with 16,384 networks, each of which can accommodate more than 60,000 computers.
Class B IP addresses range from 128.0.0.1 to 191.255.255.254.
3. Class C IP addresses
In a Class C IP address, the first three numbers are network numbers, and the remaining numbers are local computer numbers. The network ID and host ID of Class C IP addresses are 24 digits and 8 digits respectively. There are more than 2.09 million networks in Class C IP addresses. It is applicable to small-scale LAN networks. Each network can contain a maximum of 254 computers.
Class C IP addresses range from 192.0.1-223.255.255.254.
4. Class D IP addresses
Class D IP addresses were historically called multicast addresses, or multicast addresses. In Ethernet, a multicast address names a set of sites that should be applied to the network to receive a packet. The highest bit of a multicast address must be 1110, ranging from 224.0.0.0 to 239.255.255.255.
5. Class E IP addresses
Class E IP addresses start with 11110. Class E IP addresses are reserved for future and experimental use.