Different Classes of IP Address with Example and Its Use

Internet Protocol (IP) is a network layer, host-to-host delivery protocol. It means it delivers a packet from one host to the other with no knowledge about the ports within the host.

It is a connection-less protocol that makes it unreliable. Hence, it is often clubbed with TCP. TCP is a reliable protocol from the transport layer.

There are two versions of IP address. These are IPv4 and IPv6.

In this article, we discuss IPv4 address space and its different classes of IP address.

IPv4 Address:

An IP address uniquely identifies each host and router. This IP address is 32 bits long.

One of the usual IP addresses that we see.

For example, 145.10.34.3.

This address is a 32-bit address represented within system in binary form:
10010001.00001010.00100010.00000011

An IP address format is usually divided into two parts:

• Network ID: To uniquely identify the network to which the host belongs.
• Host ID: To uniquely identify the host in a particular network.

Two hosts in the same network have the same network ID part but different host ID part.

On the basis of this division, IP addresses are classified into various classes.

Following are the different classes of IP address:

• 1. Class A
• 2. Class B
• 3. Class C
• 4. Class D
• 5. Class E

Class A:

• This Class IP address always has its first bit as 0, next 7 bits as a network address and following 24 bits as the host address.
• The range of IP addresses is 0.0.0.0 to 127.255.255.255.
• This means that it allows 2^7 networks and 2^24 hosts per network.
• This class of IP address is used for the very large network. Ex. Big Organisation

Class B:

• Class B IP address always has its first bits as 10, next 14 bits as a network address and following 16 bits as the host address.
• The range of IP addresses is 128.0.0.0 to 191.255.255.255.
• This means that it allows 2^14 networks and 2^16 hosts per network.
• This class of IP address is used for a medium network like multinational companies.

Class C:

• Class C IP address always has its first bits as 110, next 21 bits as a network address and following 8 bits as the host address.
• The range of IP addresses is the first block from 192.0.0.0 to 192.0.0.255 and last block from 223.255.255.0 to 223.255.255.255.
• This means that it allows 2^21 networks and 2^8 hosts per network.
• This class is used for a small network such as small companies or colleges.

Class D:

• Class C IP address always has its first bits as 1110.
• There is no segregation of host and network addresses.
• It allows multicast which means a datagram directed to multiple hosts.

Class E:

• The address begins with 1111.
• It is reserved for future use, research and development purpose.

We can use IP address class A, B and C for subnetting and supernetting in a computer network.

IP address classes Summary:

Summarizing different classes of IP address with its range and applications:

IP address ranges for a different class in the table are theoretically calculated. There are some special IP addresses which are reserved for a special purpose.

Suppose,

IP addresses having all zero’s or one’s either in network id or host id are ruled out from all the IP address classes. These IP addresses are used for the special purpose.

A related article that you may like to read: How does Computer Network Work?