Subnetting Description

Subnetting

The art of dividing a network into subnet is called subnetting.

The importance of subnetting is to keep data inside the physical address or to funnel large no of addresses through a router to a single internal IP address.

The host bits are used for subnetting. In subnetting ,the no of hosts gets decreased but the no of subnet gets increased. Now you will understand more about routing and the definition is beginning to expand which is forwarding of data into different networks or subnetworks is called routing.

Now I will tell how to make subnet mask of a network ID. Here is the question

200.1.1.0
255.255.255.0
make 8 subnets

This is a class C network. Now the formula of subnet is 2^n where n is the no of subnet
so we have to make 8 subnets means  2^3=8
now first we create the table

128     64     32     16     8     4     2     1

now we start to fill the value of the subnet which is 3 in the table from the left hand side.

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

Now we add the no that have been fill which are 128 ,64 and 32 which gives us the total of 224. So after subnetting we get the answer which is

200.1.1.0
255.255.255.224 

Now here are some question for you to understand and practice 

1) 200.1.1.0
require 16 subnets

Sol
First we find the no subnets which is 2^4=16
now we fill the subnets in the table

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

The total is 240, now after subnetting we get 
200.1.1.0/28
255.255.255.240

2) 200.8.6.0
require 64 subnets

Sol
First we find the no subnets which is 2^6=64
now we fill the subnets in the table

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

The total is 252 ,now after subnetting we get 
200.1.1.0/30
255.255.255.252

3) 200.8.1.0
require 4 subnets

Sol
First we find the no subnets which is 2^2=4
now we fill the subnets in the table

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

The total is 192  ,now after subnetting we get 
200.1.1.0/26
255.255.255.192

4) 200.5.9.0
require 30 subnets

Sol
First we find the no subnets which is 2^5=32
now we fill the subnets in the table

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

The total is 248 ,now after subnetting we get 
200.1.1.0/29
255.255.255.248

Note:If we ever get a subnet value which is not in the 2^n , remember to pick that value ehich is closest to the given subnet.Like in the last question we have been given a subnet which is 30 so it is closest to 2^6 which is 32.