Supernetting, also called Classless Inter-Domain Routing (CIDR), is a way to aggregate multiple Internet addresses of the same class. The original Internet Protocol (IP) defines IP addresses in four major classes of address structure,

Using supernetting, the network address 192.168.0.0/24 and an adjacent address 192.168.1.0/24 can be merged into 192.168.0.0/23.

basically we can interconnect  multiple smallest network into single network

look it here

Q :- company have two network address
   1 :- 192.168.0.0/24
   2 :- 192.168.1.0/24

 we need to 500 host on single network

but according to 24 subnets we have only 254 host in single network now what we do
 let's see....

for interconnect network

1 )  192.168.0.0
2 )  192.168.1.0

let's see...                 find 500 host

192.168.0.0
192.168.1.0

we can see here 2 octet are same 8 bit + 8 bit

16 bit are same

and octet 3rd

0
1
binary conversation of this number

0 = 00000000
1 = 00000001


we can see 7 bit are same in both

so now we have 16 + 7 = 23

192.168.0.0/23   (let's find host of this subnet )

/23 bit on for network

11111111.11111111.11111110.00000000

1 = network bit
0 = host bit

network bit = 23
host bit = 9

formula to find host




29 -- 2

2*2*2*2*2*2*2*2*2 = 512 

512 - 2 = 510

now we have 510 host

let's start to given IP

 192.168.0.0 ( this is network we can't assign )
192.168.0.1 ( this first valid host IP )
192.168.0.1.... ( continue )
192.168.0.255 .. ( continue )
192.168.1.1... ( continue )
192.168.1.2..... ( continue )

 192.168.1.254 ( last valid IP )

 192.168.1.255 ( broadcast IP we can't assign )

now finally we add 2 network into single network 

 192.168.0.0
192.168.1.0

 thnks....
next will  basic Router understanding .....