Azure Classroomnotes 17/Jun/2023

Networking contd…

• To create a network initially we had network classes
  • Class A
  • Class B
  • Class C
  • Class D
  • Class E
• Creating networks using Class Based Addressing will not be closer to the needs
• Lets understand CIDR

CIDR (Classless interdomain routing)

• Creating a network of size 500

ip: 192.168.0.118
sm: 255.255.255.0

--------------------

hid size => 1 octect => 2^8 - 2 ~= 250

we want a 500 device network

sm: 11111111.11111111.11111111.00000000

network id => consecutive 1's
host id => consecutive 0's

host size => 2^ (no of 0's) - 2 => 2^8-2

2^n-2 ~= 500

2^n ~= 500
 n = 9
sm: 11111111.11111111.11111110.00000000 => 255.255.254.0

• Create a network of size 10000

number of consecutive 0's = n
number of consecutive 1's => N = (32-n)

2^n ~= 10000
n = 14
N = 32 - 14 = 18
SM: 11111111.11111111.11000000.00000000
     255.255.192.0

• Create a network of size 50 devices

number of consecutive 0's = n
number of consecutive 1's => N = (32-n)

2^n ~= 50
n = 6
N = 32-6 = 26

SM: 11111111.11111111.11111111.11000000
  : 255.255.255.192

• Figure out a subnet mask for a network with
  • 12000 devices
    2^n ~ = 12000
n = 14
N = 32 - 14 = 18
SM: 11111111.11111111.11000000.00000000
255.255.192.0
  • 8 devices
    2^n = 8 + 2
n = 4
N = 32 - 4 = 28
SM: 11111111.11111111.11111111.11110000
255.255.255.240
• CIDR Notation: x.x.x.x/N

192.168.0.0/24 => 
ip: 192.168.0.x => 192.168.0.0 - 192.168.0.255
sm: 11111111.11111111.11111111.00000000
    255.255.255.0


192.168.0.0/16
ip: 192.168.x.x  => 192.168.0.0 to 192.168.255.255
sm: 11111111.11111111.00000000.00000000

192.168.0.0/20 => 192.168.0.0 to 192.168.15.255
ip: 192.168.(x).x  => 192.168.(x).0 to 192.168.(x).255
sm: 11111111.11111111.11110000.00000000

172.16.0.0/12
ip: 172.16.0.0/12 => 172.16+0.0.0 to 172.16+15.255.255
                  => 172.16.0.0 to 172.31.255.255
sm: 11111111.11110000.00000000.00000000

192.168.128.0/20

ip: 192.168.128.0 => 192.168.128.0 to 192.168.128+15.255 (192.168.143.255)
SM: 11111111.11111111.11110000.00000000

10.64.0.0/14
ip: 10.64.0.0 => 10.64+0.0.0 to 10.64+3.255.255
              => 10.64.0.0 to 10.67.255.255
sm: 11111111.11111100.00000000.00000000

• We need
  • 2 power table: Refer Here
  • decimal to binary converter: https://www.rapidtables.com/convert/number/decimal-to-binary.html
  • binary to decimal converter: Refer Here