AWS Classroom Series – 20/Aug/2021

Solutions to Exercises

• Expand CIDR Ranges

172.16.0.0/12

nid bits = 12
host id bits = 32-12 = 20

IP: 10101100.00010000.00000000.00000000
SM: 11111111.11110000.00000000.00000000
    255.240.0.0

IP: 10101100.0001xxxx.xxxxxxxx.xxxxxxxx
    10101100.00010000.00000000.00000000 => 172.16.0.0
	10101100.00011111.11111111.11111111 => 172.31.255.255

192.168.0.0/16

SM: 255.255.0.0
IP: 192.168.0.0 - 192.168.255.255

10.0.0.0/8
SM: 255.0.0.0
IP 10.0.0.0 - 10.255.255.255


10.100.192.0/20
nid = 20
hid = 32-20 = 12

IP: 00001010.01100100.11000000.00000000
SM: 11111111.11111111.11110000.00000000
    255.255.240.0

IP: 00001010.01100100.1100xxxx.xxxxxxxx
  : 00001010.01100100.11000000.00000000 = 10.100.192.0
  : 00001010.01100100.11001111.11111111 = 10.100.207.255


10.10.0.0/21
IP: 00001010.00001010.00000000.00000000
SM: 11111111.11111111.11111000.00000000
  : 255.255.248.0
IP: 00001010.00001010.00000xxx.xxxxxxxx
  : 00001010.00001010.00000000.00000000 => 10.10.0.0
  : 00001010.00001010.00000111.11111111 => 10.10.7.255

Subnet

• This is subnetwork i.e it is a part of network
• We need to create a private network with six subnets for the following
• Private network ranges: When we create any private network it has to be in the following ranges
  • 10.0.0.0/8
  • 172.16.0.0/12
  • 192.168.0.0/16
• Total organization devices ~= 6000

2^n - 2 ~= 6000
2^n ~= 6000
n = 13
host bits = 13
network id = 32-13 => 19

• So lets choose 192.168 series

192.168.0.0/19

IP: 11000000.10101000.000xxxxx.xxxxxxxx
SM: 11111111.11111111.11100000.00000000

• So the total organization network cidr 192.168.0.0/19
• Now we need to create subnet cidrs.
• Each subnet requires 1000 devices

2^n ~= 1000
n = 10
host id bits for subnet = 10
network id bits = 22

IP: 11000000.10101000.000xxxxx.xxxxxxxx
SM: 11111111.11111111.11100000.00000000


IP: 11000000.10101000.000xxxxx.xxxxxxxx


subnet:


N-SM: 11111111.11111111.11100000.00000000
S-SM: 11111111.11111111.11111100.00000000

N-IP: 11000000.10101000.000xxxxx.xxxxxxxx

S-IP: 11000000.10101000.000xxxyy.yyyyyyyy

Possible

F1: 11000000.10101000.000000yy.yyyyyyyy => 192.168.0.0/22
F2: 11000000.10101000.000001yy.yyyyyyyy => 192.168.4.0/22
F3: 11000000.10101000.000010yy.yyyyyyyy => 192.168.8.0/22
F4: 11000000.10101000.000011yy.yyyyyyyy => 192.168.12.0/22
F5: 11000000.10101000.000100yy.yyyyyyyy => 192.168.16.0/22
F6: 11000000.10101000.000101yy.yyyyyyyy => 192.168.20.0/22

• Exercise: Create a private network with 3 subnets
  • Each subnet requires 25000 devices to be connected