Subnetting Calculation

What is Subnet??

Subnets are a type of network that allows an organisation to have a large square of addresses without having to create many organisations or split the addresses into subnets. The rest of the world considers the affiliation to be a single factor. Nonetheless, there are a few subnets on the inside. All messages are sent from the router address, which connects the connection to the rest of the Internet; the router then routes the message to the appropriate subnets.

In this section, we are expecting to to show calculation on how to identify the IP address that was assigned for the  OnlineLearning System Server based on the information given in the project scenario.

 

Let's Use Fixed-Length Subnet Mask (FLSM) as an example :

Based on the given scenario, we choose class C and class A respectively for home network and Cobham College Campus network and assume that Cobham College Campus has 5 department including IT Center, therefore there will be 5 subnetwork as well. 

Let's set :

Private Ip address(Cobham College Campus)  : Class A ( 10.0.0.0/8 )

Subnet Mask for class A =  255.0.0.0

 

NETWORK	HOST	HOST	HOST
255	0	0	0

 

 

2 ^ BB >= 5 subnetwork needed

Bit borrowed = 3 , therefore 3 bit borrowed to determine the IP range between subnetwork. 

Bit left = 32(overall bit which is 4 octet of ip address) - 8(First octet is subnet mask for class A) - 3(Bit borrowed) = 21 bit , so basically this 21 bit of binary we can change to determine ip range between subnetwork or department.

 

Number of host per subnet = ( 2^Bit Left ) - 2       

                                            = ( 2 ^ 21 ) -2

                                            =  2 097 150 of IP address that we can get

 

Why is it necessary to subtract 2 in this formula? Because there is one address for the subnet and another for the broadcast address.....

Table below are the result of the calculation of IP address between subnetwork. 

SUBNET NUMBER	IP NUMBER
0	Network Address	10.0000 0000.0000 0000.0000 0000
	IP Address Range	10.0000 0000.0000 0000.0000 0001 10.0001 1111.1111 1111.1111 1110
	Broadcast Address	10.0001 1111.1111 1111. 111 1111
1	Network Address	10.0010 0000.0000 0000.0000 0000
	IP Address Range	10.0010 0000.0000 0000.0000 0001 10.0011 1111.1111 1111.1111 1110
	Broadcast Address	10.0011 1111.1111 1111.1111 1111
2	Network Address	10.0100 0000.0000 0000.0000 0000
	IP Address Range	10.0100 0000.0000 0000.0000 0001 10.0101 1111.1111 1111.1111 1110
	Broadcast Address	10.0101 1111.1111 1111.1111 1111
3	Network Address	10.0110 0000.0000 0000.0000 0000
	IP Address Range	10.0110 0000.0000 0000.0000 0001 10.0111 1111.1111 1111.1111 1110
	Broadcast Address	10.0111 1111.1111 1111.1111 1111
4	Network Address	10.1000 0000.0000 0000.0000 0000
	IP Address Range	10.1000 0000.0000 0000.0000 0001 10.1001 1111.1111 1111.1111 1110
	Broadcast Address	10.1001 1111.1111 1111.1111 1111

The last Subnet will be design for router which is subnet 4.

Home Address Network : 1 SUBNET ONLY

Private Ip address : Class C ( 192.168.0.0 )

Subnet Mask for class C =  255.255.255.0

NETWORK	NETWORK	NETWORK	HOST
255	255	255	0

 

Bit Borrowed = 2^BB >= 1 subnetwork only needed

                       = 0 , therefor 0 bit borrowed, so the last octet of ip in binary form will be from 0000 0000 until 1111 1110.

SUBNET NUMBER	IP NUMBER
0	Network Address IP Address Range Broadcast Address	192.169.0.0 192.168.0.1 192.168.0.254 192.168.0.255