Networking contd

• Now lets create a network which can accomodate 2000 devices Refer Here for table of values

hosts size = 2000
number of bits for host

2^n ~= 2000
n = 11

ipaddress: x.x.x.x/32-n
         : x.x.x.x/21
         : 10.0.0.0/21 or
         : 172.16.0.0/21
         : 192.168.0.0/21

subnet mask: 11111111.11111111.11111000.00000000
            255.255.248.0

• Generally we choose ip address which are reserved for private networking. private cidrs are
  • 10.0.0.0/8
  • 172.16.0.0/12
  • 192.168.0.0/16
• Lets try to create a network which can accomodate 100000 devices

host size = 100000
2^n ~= 100000
n = 17

ip address: x.x.x.x/32-17 => x.x.x.x/15
         : 10.0.0.0/15
         :172.16.0.0/15

subnet mask: 11111111.11111110.00000000.00000000
             255.254.0.0

• Generally we will not create one huge network, we will break huge network into multiple smaller sub networks, and this is called as subnet. Subnet should have network id which is equal or greater than main network

network: 10.10.0.0/16  => 2^16 => network id : 10.10
correct subnet: 10.10.0.0/24 => 2^8 => network id => 10.10.0
correct subnet: 10.10.0.0/16 => 2^16 network id: 10.10
wrong subnet: 10.10.0.0/15  => 2^17

• Lets try to create 3 subnets of size to connect 200 devices in a network with range 192.168.0.0/16

network : 192.168.0.0/16
subnet mask: 255.255.0.0

host size ~= 200
2^n ~=200
n = 8

subnet1:

ip address => 192.168.0.0/24
subnet mask => 255.255.255.0

subnet2:
192.168.1.0/24

subnet3:
192.168.2.0/24

• Lets try to create 3 subnets subnet1 with 200 devices subnet2 and subnet 3with 500 devices from a network of 172.16.0.0/16

network: 172.16.0.0/16

subnet1 :
host size: 200
2^n ~= 200
n = 8
subnet: 172.16.0.0/24

subnet2:
host size: 500
2^n ~= 500
n = 9
172.16.2.0/23

subnet3:
host size: 500
2^n ~= 500
n = 9
172.16.4.0/23

• Lets try to create 4 subnets of size 1000 each in the network 192.168.0.0/20

network: 192.168.0.0/20
subnet with 1000
2^n ~= 1000
n = 10

192.168.0000    00    00. 00000000

subnet1 = 192.168.0.0/22

subnet2 = 192.168.4.0/22

subnet3 = 192.168.8.0/22

subnet4 = 192.168.12.0/22

• Exercise: Create a subnets for each floor as mentioned in the below image

Router

• Router is a networking component which can forward packets from one network to other
• Default gateway is ip address of your router
• Execute the following command

tracert google.com

• In the router routing rules are configured. This is called route table.