In this post I will try to explain the Basic operations we will use for subnetting.

conversions

• Binary to Decimal
• Decimal to Binary
  
  
  

Binary to Decimal

The decimal number is equal to the sum of binary digits (dn) times their power of 2 (2n).

For networking we will use the table down below

Reference table

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

Example:
convert 101101
we set each 1 from right to left

we add the value of each result together to get 45

Decimal to Binary

Reference table

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

Example:
convert 78
we compare 78 to every value on table.

78 >= 128 = No 
78 >= 64  = YES -> 78 - 64 = 14  
14 >= 32  = NO  
14 >= 16  = NO  
14 >= 8   = YES -> 14 - 8  = 6
6  >= 4   = YES -> 6  - 4  = 2
2  >= 2   = YES -> 2  - 2  = 0
0  >= 1   = NO

we replace every yes by 1 on reference table

27	26	25	24	23	22	21	20
128	64	32	16	8	4	2	1
0	1	0	0	1	1	1	0

78 = 01001110