CLASS FULL v/s CLASS LESS Subnetting


Classful networks use the 'classful' subnet mask according to the leading bits in the first block of the IP address:
Class A begins with binary 0 (0-127.x.x.x)
So and IP address 0.0.0.0 to 127.255.255.255 use subnet mask = 255.0.0.0
/8
 
Class B begins with binary 10 (128-191)
So IPaddresses 128.0.0.0 to 192.255.255.255 use subnet mask = 255.255.0.0
/16

Class C begin with binary 110 (192-223)
So IP addresses 192.0.0.0 to 255.255.255.0 use a subnet mask = 255.255.255.0
/24


Classless IP addressing means you can use any subnetmask you want, even assigning partial blocks. For example subnet 192.168.1.0 is a class C network.
But you have two physical interfaces on your router that connect to 3 switches   Classless routing allows me to break up this IP address into more useful segments.

let see.....


in this pic...
we have three block A,B,C
and ip are using 192.168.1.0/24

Q :-  1 we can you use only this network 192.168.1.0
        2 BLOCK A have 30 client , same as BLOCK B,C


NOW WE HAVE TO CLASS LESS SUBNETTING TO SPRAT THREE NEWORK IN SINGAL NETWROK OK

let see...

we have netwrok 192.168.1.0 this network belong to CLASS C
so... 192.168.1.0/24 ( by default 254 host keep in /24)

now we have to find out 30 host

now use my logic ...

formula to find out proper CIDR  for 30 host

       n
= ( 2  -2 ) formula to find CIDR for 30 host
 
     0
   2 -2 = -1

    1
   2 -2 =  1

   2
  2 -2 =  2

   3
  2 -2 =  6
 
   4
  2 -2 =  14

   5
  2 -2 =  30

stop it here way  we need 30 host

(note : - value should be equal ya greater but not less then acording given host )

now we have power 5

let see..

192.168.1.0


5 power host we keep and all is network

11111111.11111111.11111111.11100000

 1 = network bit 
0 = host bit

                 192.168.1.0/27
sub-mask  
   11111111.11111111.11111111.11100000
   255.255.255.224
(in last octet three on bit will add 128+64+32 =224)
  

calculate HOST AND NETWORK

formula of host





now we have no of host is 5
              5
Ans  :-  2  - 2    = ?
  
           32 - 2  = 30  HOST

 Assign host to BLOCK A 

192.168.1.0  this is network (we never assign network )
192.168.1.1 (this is valid ip to assign pc )
192.168.1.2....
192.168.1.30
192.168.1.31 (this is broadcast ip never assign )

192.168.1.32 (this is new network continue  )
 Assign host to BLOCK B 

 192.168.1.32 (this is network never assign )
192.168.1.33 (this is valid ip to assign pc )
192.168.1.34...
192.168.1.62
192.168.1.63 ( this is broadcast ip never assign )

 192.168.1.64 (this is new network continue )
Assign host to BLOCK C

192.168.1.64  (this is network never assign )

192.168.1.65  (this is valid ip to assign pc )
192.168.1.66....
192.168.1.94 
192.168.1.95  ( this is broadcast ip never assign )

192.168.1,96  (this is new network continue future  )

 look at here ... 
   1 network/broadcast we never assign to pc 
   2 new network will addition   of 32 suppose 32 is my new network so 32 + 32 = 64 is next network 
      same 64 + 32 = 96  new network
     
(if any problem in explanation mention in comment i will be help for you thnks....)

 

try it .....


192.168.1.0/28

192.168.2.0/26

192.168.1.0/30

find there host and network and type in comment thnks....