176

A 0 in each position indicates that the value for that position is not added to the total. A 0 in every position yields a total of 0, as follows in Table 6-3.

Table 6-3	Binary Positional Notation with Digit of 0
Decimal Value		128	64	32	16	8	4	2	1
Binary Digit		0	0	0	0	0	0	0	0
Position Value		0	0	0	0	0	0	0	0

For the conversion of a 32-bit IPv4 address, you identify the 4 bytes or octets that make up this address. You then convert each of these four octets to decimal. As an example, convert the IPv4 address 10101100000100000000010000010100 to the bytes of a dotted decimal address. The conversion starts with the low-order bits, in this case byte 00010100, and con-tinues up to the high-order byte.

How To

Step 1.      Divide the 32 bits into 4 octets, as follows:

10101100.00010000.00000100.00010100

Step 2.      Convert the low-order byte 00010100 first, as seen in Table 6-4.

Step 3.      Convert the next-highest byte, which is 00000100, as seen in Table 6-5.

Step 4.      Continue converting with the next byte, 00010000, as seen in Table 6-6.

Step 5.      Convert the highest byte, 10101100, as seen in Table 6-7.

Step 6.      Write down the four numbers with dots separating the octets, such as 172.16.4.20.

Table 6-4	Conversion of Binary Number 00010100
Decimal Value		128	64	32	16	8	4	2	1
Binary Digit		0	0	0	1	0	1	0	0
Position Value		0	0	0	16	0	4	0	0
Total Value				0 + 0 + 0 + 16 + 0 + 4 + 0 + 0 = 20
Table 6-5	Conversion of Binary Number 00000100
Decimal Value		128	64	32	16	8	4	2	1
Binary Digit		0	0	0	0	0	1	0	0
Position Value		0	0	0	0	0	4	0	0
Total Value			0 + 0 + 0 + 0 + 0 + 4 + 0 + 0 = 4