Subnetting of Class C IP address

Subnetting of Class C IP address

In the Class C address only 8 bits are available to define the host part in the address. In this class the subnet bit starts at the left and go to right. The Class C Subnet mask can be following-

Binary form               decimal form

10000000                   128

11000000                   192

11100000                    224

11110000                    240

11111000                    248

11111100                    252

There are lots of question arise when subnetting a network like how many valid subnet, how may host per subnet, what is the broadcast id for each subnet etc.

In Class C network we can take an example like-

Network Address is- 192.168.10.0

Subnet Mask- 255.255.255.192

Now the question are-

1. How many subnet we can define in this network address-

The formula for determining the subnet is – 2ⁿ

Where n is the number of bit that is borrowed.

192=11000000

In this case the borrowed bit is 2 so the number of subnet is -2²=4

2. How many hosts per subnet we can define.

The formula for determining the number of host per subnet is – 2ⁿ-2

Where n is number of host bits that is 6.

192=11000000

In this case 6 host bit and the number of the host per subnet-2⁶-2=62hosts.

3. What are the valid subnets-?

The formula for determining the valid subnet is –

256-decimal value of number of borrowed bit

256-11000000

256-192=64

And we start the valid subnet from 0 to 192.

0, 0+64=64, 64+64=128,128+64=192

So there are four subnets -0, 64,128,192

First subnet-192.168.10.0

First host-192.168.10.1

Last host-192.168.10.62

Broadcast address-192.168.10.63

Second Subnet-192.168.10.64

First host-192.168.10.65

Last host-192.168.10.126

Broadcast address-192.68.10.127

Third Subnet-192.168.10.128

First host-192.168.10.129

Last host-192.168.10.190

Broadcast address-192.168.10.191

Fourth Subnet-192.168.10.192

First host-192.168.10.193

Last host-192.168.10.254

Broadcast address-192.168.10.255