Subnetting

• Dividing a Single Network into Multiple Networks.
• Converting Host bits to Network Bits 
   i.e. Converting 0’s into 1’s
• Subnetting is also called as FLSM (Fixed Length Subnet Mask)
• Subnetting can be done in three ways.

1. Requirement of Network
2. Requirement of Host
3. Cisco / Notation

Scenario

ZOOM Technologies is having 100 PC

• Which Class IP addresses you will using in the network ?
   Answer : Class C.
• In ZOOM Technologies we have Five Departments with 20 Pcs each

ZOOM Technologies – 192.168.1.0/24

• Administrator Requirement 
   Inter-department communication should not be possible ? 
   
   Solution.
   Allocate a different Network to each Department
   i.e.

• In the above Scenario inter-department communication is not possible.

Main Aim of Subnetting

Problem with the previous Scenario is :-

• Instead of 20 machine Broadcasting, you doing broadcasting for 254 machine, Loss of bandwidth.
• More Wasting of IP addresses (Approximately 1000)
• Security
  
  
  

Power table

Some Important Values

Requirement of Networks is 5 ?
Example – 1

 
Class C : 192.168.1.0

If you convert 3 Host Bits to Network Bits
6 Subnet & 30 Hosts/Subnet

                              Customize Subnet Mask
                                    255.255.255.224

                                                Subnet Range
                                 192.168.1.32    to   192.168.1.63    ->MCSE .
                                 192.168.1.64    to   192.168.1.95    -> CISCO .
                                 192.168.1.96    to   192.168.1.127  ->FIREWALL
                                 192.168.1.128  to   192.168.1.159  ->SOLARIS
                                 192.168.1.160  to  192.168.1.191  ->TRAINING
                                 192.168.1.192  to  192.168.1.223  -> Future Use

Requirement of Networks is 14 ?
Example – 2 

lass C : 192.168.1.0

Try to do the calculation ?

Example – 2

Example – 3

Example – 4

Example – 5

bit to network bit.

Example – 6

Requirement of Hosts is 40 ?
Example – 1 

Requirement of Hosts is 2 ?
Example – 2 

Cisco / Notation
Example – 1 

Requirement of Networks is 2 ?
Example – 1 




Requirement of Hosts is 126 ?
Example – 2

Cisco / Notation
Example – 3