Variable Length Subnetmask !!!!!!!!!!!!!
IP ADDRESS : 192.168.20.0/24 Class C Network !!!
Network A : 50 Hosts
Network B : 27 Hosts
Network c : 12 Hosts
Network D : 12 Hosts
Network E : 2 Hosts
Network F : 2 Hosts
Network G : 2 Hosts
Network H : 2 Hosts
So the Number of Networks = 8 Networks
192.168.20. 0
1 1 1 1 1 1 1 1
NN HHHHHH
h
2 - 2 = --
6
2 - 2 = 62
n
2 = Nummber of Subnets
2
2 = 4 Subnets
00 000000 = 0
01 000000 = 64 => this is for Network A
10 000000 = 128
11 000000 = 192
N N
128 64 32 16 8 4 2 1
Subnet masks for Network A 255.255.255.192 or by CIDr 192.168.20.0/26
( borrowed 2 N from Hosts )
so Network A from 192.168.20.64 to 192.168.20.127
2nd we will subnetting for Network B from 192.168.20.128 to 192.168.20.191
its mean 10 000000 = 128
h
2 - 2 = --
5
2 - 2 = 30
NNN HHHHH
but in Network A we used 2 N
but in Network B we using 3 N so
1 0 N HHHHH
this N for 0 and for 1
1 0 0 HHHHH so Network B 128
1 0 1 HHHHH
Subnetmask for Network B = 255.255.255.224 or by CIDR = 26 + 1 Extra bit
192.168.20.128/27
( borrowed 3 N from Hosts )
so its still found two Networks from 128 to 159 and from 160 to 191
Next 2 Network c and d
from 160 to 191
it means 1 0 1 N HHHH
for Network C = 12 Hosts
its mean
h
2 - 2 = ---
4
2 - 2 = 14 Hosts
NNNN HHHH
1 0 1 0 HHHH 160 this is for Network C to 175
1 0 1 1 HHHH 176 this is for Network D to 191
Subnet mask 255.255.255.240 and by CIDR /28 = 27 + 1 Extra bit
because C and D in the same value of Number of Hosts
Network c : 12 Hosts
Network D : 12 Hosts
about A , B , C , D
this is my Network
00000000 192.168.20.0/26 Network Address Unvalid
01000000 192.168.20.64/24 Network A
10000000 192.168.20.128/27 Network B
10100000 192.168.20.160/28 Network C
10110000 192.168.20.176/28 Network D
11000000 192.168.20.192/26 Broadcast Address Unvalid
but about this Range from 192.168.20.1 to 192.168.20.63 its Valid IP Addresses
and can use it so we can use this point to point Networks for Network E , Network F , Network G
Network H
so now lets make network for E, F, G, H
h
2 - 2 = --
2
2 - 2 = 2 we just need 2 hosts so its valid
about first ip 192.168.20.0/26 00000000
00 NNNN 00
but we need just 2 H
so NNNN for represent 4 Extra bits like this :
00 000000 = 0
01 000000 = 64
10 000000 = 128 001 010 011 0010 0001 0011 00001 00010 00011 ..etc
11 000000 = 192
represent 2 Hosts bits
and about 4N bits u can give it 16 Subnets
its mean you can subnet it for
0000 0000 0/30 0 - 3 first host 1 last one 2
0000 0100 4/30 4 - 7 first host 5 last host 6
0000 1000 8/30 8 - 12 first host 9 last 10
0000 1100 12/30
0001 0000 16/30
-
-
-
-
0011 1000 56/30
0011 1100 60/30
this is My All Networks
0000 0000 192.168.20.0/30 Network E
0000 0100 192.168.20.4/30 Network F
0000 1000 192.168.20.8/30 Network G
0000 1100 192.168.20.12/30 Network H
0001 0000 192.168.20.16/30 For future Growth
01000000 192.168.20.64/24 Network A
10000000 192.168.20.128/27 Network B
10100000 192.168.20.160/28 Network C
10110000 192.168.20.176/28 Network D
Enjoy !!!
