What is IP address? Discuss about IP address

In the global network Internet, each node is identified with unique number called IP address. The IP address of a machine is an array of four numbers separated by period, as shown below:

18.10.200.14
185.25.85.141

Each number in the above array is an eight-bit integer (That is it is between 0 and 255 and called an Octet). There are three classes of networks in the Internet depending on the numbers of hosts it can handle. They are
Class A networks
Class B networks
Class C networks

Class A networks can handle a large number of hosts. Class B networks are capable of handling a moderate number of hosts.

Class C networks can handle only a small number of hosts. The maximum number of hosts handled by each network are tabulated.

The first octet of a Class A network IP address represents the network ID and has a value from 1 to 126. So, there are only 126 Class A networks. However for each Class A network the second, third and the fourth octet represent the host ID, which can be any number between 0 and 256 and hence can have 16,177,214 hosts. (Note: 256 * 256 * 256 =16,177,216).
The general form of an IP address of a Class A network host is

N.H1.H2.H3.

Where

N ranges from 1 to 126
H1, H2, H3 are numbers from 0 to 255.

The first octet of a Class B network IP address is a value from 128 to 191. The general format of a Class B network IP address is
N1.N2.H1.H2

Where

N1 ranges from 128 to 191 N2 ranges from 0 to 255
N1 and H2 may range from 0 to 255.

N1 and N2 form the network ID and H1 and H2 represent the host ID. There can be up to 16,384 Class B networks on the Internet, each of which can have up to 65,534 hosts.
(Note: N1 takes one of the 64 values from 128 to 191 and N2 takes 0 to 255. 254 * 254 = 65536)

Class C networks are designed to handle the situation where there would be very large number of networks that contained a small number of networks which in turn contained a small number.