Class A - 4 Bit Subnetting

If we include four bits from the host part to the network part, the subnet mask is changed to 255.240.0.0.

00001010.0000 | 0000.00000000.00000000
11111111.1111 | 0000.00000000.00000000

The four bits added to network part can have sixteen possible values in second octet and that are 0000, 0001, 0010, 0011, 0100, 0101, 0110, 0111, 1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111.

 

SN No	Description	Binaries	Decimal
1	Network Address	00001010.00000000.00000000.00000000	10.0.0.0
	First IP Address	00001010.00000000.00000000.00000001	10.0.0.1
	Last IP Address	00001010.00001111.11111111.11111110	10.15.255.254
	Broadcast Address	00001010.00001111.11111111.11111111	10.15.255.255
2	Network Address	00001010.00010000.00000000.00000000	10.16.0.0
	First IP Address	00001010.00010000.00000000.00000001	10.16.0.1
	Last IP Address	00001010.00011111.11111111.11111110	10.31.255.254
	Broadcast Address	00001010.00011111.11111111.11111111	10.31.255.255
3	Network Address	00001010.00100000.00000000.00000000	10.32.0.0
	First IP Address	00001010.00100000.00000000.00000001	10.32.0.1
	Last IP Address	00001010.00101111.11111111.11111110	10.47.255.254
	Broadcast Address	00001010.00101111.11111111.11111111	10.47.255.255
4	Network Address	00001010.00110000.00000000.00000000	10.48.0.0
	First IP Address	00001010.00110000.00000000.00000001	10.48.0.1
	Last IP Address	00001010.00111111.11111111.11111110	10.63.255.254
	Broadcast Address	00001010.00111111.11111111.11111111	10.63.255.255
5	Network Address	00001010.01000000.00000000.00000000	10.64.0.0
	First IP Address	00001010.01000000.00000000.00000001	10.64.0.1
	Last IP Address	00001010.01001111.11111111.11111110	10.79.255.254
	Broadcast Address	00001010.01001111.11111111.11111111	10.79.255.255
6	Network Address	00001010.01010000.00000000.00000000	10.80.0.0
	First IP Address	00001010.01010000.00000000.00000001	10.80.0.1
	Last IP Address	00001010.01011111.11111111.11111110	10.95.255.254
	Broadcast Address	00001010.01011111.11111111.11111110	10.95.255.255
7	Network Address	00001010.01100000.00000000.00000000	10.96.0.0
	First IP Address	00001010.01100000.00000000.00000001	10.96.0.1
	Last IP Address	00001010.01101111.11111111.11111110	10.111.255.254
	Broadcast Address	00001010.01101111.11111111.11111110	10.111.255.255
8	Network Address	00001010.01110000.00000000.00000000	10.112.0.0
	First IP Address	00001010.01110000.00000000.00000001	10.112.0.1
	Last IP Address	00001010.01111111.11111111.11111110	10.127.255.254
	Broadcast Address	00001010.01111111.11111111.11111111	10.127.255.255
9	Network Address	00001010.10000000.00000000.00000000	10.128.0.0
	First IP Address	00001010.10000000.00000000.00000001	10.128.0.1
	Last IP Address	00001010.10001111.11111111.11111110	10.143.255.254
	Broadcast Address	00001010.10001111.11111111.11111111	10.143.255.255
10	Network Address	00001010.10010000.00000000.00000000	10.144.0.0
	First IP Address	00001010.10010000.00000000.00000001	10.144.0.1
	Last IP Address	00001010.10011111.11111111.11111110	10.159.255.254
	Broadcast Address	00001010.10011111.11111111.11111111	10.159.255.255
11	Network Address	00001010.10100000.00000000.00000000	10.160.0.0
	First IP Address	00001010.10100000.00000000.00000001	10.160.0.1
	Last IP Address	00001010.10101111.11111111.11111110	10.175.255.254
	Broadcast Address	00001010.10101111.11111111.11111111	10.175.255.255
12	Network Address	00001010.10110000.00000000.00000000	10.176.0.0
	First IP Address	00001010.10110000.00000000.00000001	10.176.0.1
	Last IP Address	00001010.10111111.11111111.11111110	10.191.255.254
	Broadcast Address	00001010.10111111.11111111.11111111	10.191.255.255
13	Network Address	00001010.11000000.00000000.00000000	10.192.0.0
	First IP Address	00001010.11000000.00000000.00000001	10.192.0.1
	Last IP Address	00001010.11001111.11111111.11111110	10.207.255.254
	Broadcast Address	00001010.11001111.11111111.11111111	10.207.255.255
14	Network Address	00001010.11010000.00000000.00000000	10.208.0.0
	First IP Address	00001010.11010000.00000000.00000001	10.208.0.1
	Last IP Address	00001010.11011111.11111111.11111110	10.223.255.254
	Broadcast Address	00001010.11011111.11111111.11111111	10.223.255.255
15	Network Address	00001010.11100000.00000000.00000000	10.224.0.0
	First IP Address	00001010.11100000.00000000.00000001	10.224.0.1
	Last IP Address	00001010.11101111.11111111.11111110	10.239.255.254
	Broadcast Address	00001010.11101111.11111111.11111111	10.239.255.255
16	Network Address	00001010.11110000.00000000.00000000	10.240.0.0
	First IP Address	00001010.11110000.00000000.00000001	10.240.0.1
	Last IP Address	00001010.11111111.11111111.11111110	10.255.255.254
	Broadcast Address	00001010.11111111.11111111.11111111	10.255.255.255

The network 10.0.0.0 is divided into sixteen networks, each network has 1048576 total IP addresses and 1048574 usable IP addresses (two IP addresses are used in each subnet to represent the netwok id and the broadcast id).

From the above examples, you can clearly understand how to subnet a Class A network.

Class A Subnetting can be summerized as below.

Subnet Bits	Subnet Mask	CIDR	Total Subnets	Usable IP Address/Subnet
0	255.0.0.0	/8	1	16777214
1	255.128.0.0	/9	2	8388606
2	255.192.0.0	/10	4	4194302
3	255.224.0.0	/11	8	2097150
4	255.240.0.0	/12	16	1048574
5	255.248.0.0	/13	32	524286
6	255.252.0.0	/14	64	262142
7	255.254.0.0	/15	128	131070
8	255.255.0.0	/16	256	65534
9	255.255.128.0	/17	512	32766
10	255.255.192.0	/18	1024	16382
11	255.255.224.0	/19	2048	8190
12	255.255.240.0	/20	4096	4094
13	255.255.248.0	/21	8192	2046
14	255.255.252.0	/22	16384	1022
15	255.255.254.0	/23	32768	510
16	255.255.255.0	/24	65536	254
17	255.255.255.128	/25	131072	126
18	255.255.255.192	/26	262144	62
19	255.255.255.224	/27	524288	30
20	255.255.255.240	/28	1048576	14
21	255.255.255.248	/29	2097152	6
22	255.255.255.252	/30	4194304	2

In this Class A Subnetting Tutorial - Part 2, You have learned how to perform a Class A 4 bit subnetting. Click "Next" to continue.

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