1 / 3
amogtech
2 / 3
mhk
3 / 3
ccg


 There are four octet in IPV4. Each octet has 8 bits. So, there are 32 bits in IPV4. IPV4 is based on binary (0, 1) and decimal (0 to 9).

       1st Octet                               2nd Octet                         3rd Octet                         4th Octet

        8 bits                                     8 bit                                  8 bits                           8 bits

27 26 25 24 23 22 21 20       27 26 25 24 23 22 21 20         27 26 25 24 23 22 21 20        27 26 25 24 23 22 21 20

  255.255.255.255                   255.255.255.255                255.255.255.255                 255.255.255.255

 

How to become 255.255.255.255 ? As each octet has 8 bit and is based on binary....

27 = 128,  26 = 64,  25 = 32, 24 = 16,  23 = 8,  22 = 4, 21 = 2,  20 = 1

128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255

 

Let's try to change from the Decimal to the Binary....

              

   Decmial                                                                            Binary

1st Octet     2nd Octet    3rd Octet   4th Octet                 1st Octet      2nd Octet     3rd Octet      4th Octet

192       .    168         .       1      .     0              =        11000000  . 10101000  . 00000001 .  00000000

223       .    200         .      100   .     25             =        11011111  .  11001000  . 01100100 . 00011001

172       .    16          .       31     .    87             =        10101100  .  00010000  . 00011111 .  01010111

 

Let's explore 192.168.1.0/24....

1st Octet                                2nd Octet                           3rd Octet                           4th Octet

        8 bits                                  8 bit                                 8 bits                                8 bits

27 26 25 24 23 22 21 20       27 26 25 24 23 22 21 20         27 26 25 24 23 22 21 20        27 26 25 24 23 22 21 20

  255.255.255.255               255.255.255.255                  255.255.255.255                 255.255.255.255

                                               Network                                                                        Host

 

Network Address = 192.168.1.0

Subnet Mask = 255.255.255.0

Usable IP Addresses = 192.168.1.1 to 192.168.1.254

Broadcast Address = 192.168.1.255

 

 

 Let's explore 192.168.1.0/25....

1st Octet                             2nd Octet                          3rd Octet                           4th Octet

        8 bits                                  8 bit                                 8 bits                                8 bits

27 26 25 24 23 22 21 20       27 26 25 24 23 22 21 20         27 26 25 24 23 22 21 20        27 26 25 24 23 22 21 20

  255.255.255.255               255.255.255.255                  255.255.255.255                 255.255.255.255

                                               Network                                                                        Host

 

1st Network Address = 192.168.1.0

Subnet Mask = 255.255.255.128

Usable IP Addresses = 192.168.1.1 to 192.168.1.126

Broadcast Address = 192.168.1.127

 

2nd Network Address = 192.168.1.128

Subnet Mask = 255.255.255.128

Usable IP Addresses = 192.168.1.129 to 192.168.1.254

Broadcast Address = 192.168.1.255

 

 

 Let's explore 192.168.1.0/26....

1st Octet                             2nd Octet                          3rd Octet                           4th Octet

        8 bits                                  8 bit                                 8 bits                                8 bits

27 26 25 24 23 22 21 20       27 26 25 24 23 22 21 20         27 26 25 24 23 22 21 20        27 26 25 24 23 22 21 20

  255.255.255.255               255.255.255.255                  255.255.255.255                 255.255.255.255

                                               Network                                                                        Host

 

1st Network Address = 192.168.1.0

Subnet Mask = 192.168.1.192

Usable IP Addresses = 192.168.1.1 to 192.168.1.62

Broadcast Address = 192.168.1.63

 

2nd Network Address = 192.168.1.64

Subnet Mask = 192.168.1.192

Usable IP Addresses = 192.168.1.65 to 192.168.1.126

Broadcast Address = 192.168.1.127

 

3rd Network Address = 192.168.1.128

Subnet Mask = 192.168.1.192

Usable IP Addresses = 192.168.1.129 to 192.168.1.190

Broadcast Address = 192.168.1.191

 

4th Network Address = 192.168.1.192

Subnet Mask = 192.168.1.192

Usable IP Addresses = 192.168.1.193 to 192.168.1.254

Broadcast Address = 192.168.1.255

 

(Note: The Subnet Mask is reverse proportional to host range. The larger the subnet mask, the smaller the host range.)

 

The following table is formula for Ipv4 addresses (Class C). I've made it when I was in Singapore Polytechnic.

 

Binary        Decimal       Prefix          Subnet Mask        Count of Networks   Usable Ip Range

    -              -                /24           255.255.255.0                 1                      254                 
 

27               128             /25           255.255.255.128              2                     126                 

                    +

26                64             /26           255.255.255.192              4                       62                   
                    +

25                32             /27           255.255.255.224              8                       30                   

                    +

24               16             /28            255.255.255.240             16                      14                            

                    +

23                8              /29            255.255.255.248             32                       6

                   +

22                4             /30             255.255.255.252             64                        2                       


Share On:

What do you think?

Send us feedback!