SUBNNETTING | How to Subnet a Network? | PART 2 | Binary Numbers

How to Subnet a Network? | PART 2 | Binary  Numbers

To understand network addresses, we should take a moment to consider the binary number system. Since all electronic devices only understand binary numbers, all network addresses are actually made up of binary digits called bits. An IP address consists of 32 bits, broken into four parts called octets. Each octet equals 8 bits. Our sample network address of 192.168.1.0, looks like this in binary.

11000000	10101000	00000001	00000000
192	168	1	0

But how does 11000000 equate to 192? How does 10101000 equate to 168? Here's how .

            A bit can have only two possible values: on, which is represented by a 1, or off, which is represented by a 0.. To represent the decimal number 0, as in the last octet above, all 8 bits are turned off. When turned on, each bit has a value. Let's take a look at one 8-bit octet , since each octet contains a distinct number. The values are as follow:

Bit	1	1	1	1	1	1	1	1
Bit value	128	64	32	16	8	4	2	1

             

              

               The right-most bit has a value of 1, the next bit has a value of 2, the next bit has a value of 4, and so on as shown in the chart above. The decimal value of an octet is the sum of the bit values. So if all bits are on, the value of the octet is 255, or 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1

                 The following table shows that 11000000 equals 192 in decimal. The bit with a value of  128 and the bit with a value of 64 are turned on, so we add 128 + 64 and get 192

Bit	1	1	0	0	0	0	0	0
Bit value	128	64	32	16	8	4	2	1

This table shows that 10101000 equals 168 in decimal. The bits with values of 128, 32, and 8 are turned on, and their sum equals 168.

Bit	1	0	1	0	1	0	0	0
Bit value	128	64	32	16	8	4	2	1