Subnet Calculation

Subnet calculation with example;

How many Subnets and hosts we can have with 192.168.1.0/27?

First determine which class this IP address falls to-> Class c, netmask of /24
       -Therefore 27-24=3 we have 3 bits for Net. we can have 2^3=8 Subnet

Second to determine number of Host in each subnet calculate how many bits you have by subtracting /27 of 32.
       -Therefore 32-27=5  we have 2^5=32 when it gives us 30 valid hosts first and last  number is Subnet address and Broadcast address accordingly.

See the full answer below and try to practice it yourself afterward.


192.168.1.0/27

Class C: 27-24=3 -> 8 subnets

32-27=5 ->2^5=32 ->30 hosts in each subnet

Subnet1: 192.168.1.0             192.168.1.1->192.168.1.31
Subnet2: 192.168.1.32           192.168.1.33->192.168.1.63    
Subnet3: 192.168.1.64           192.168.1.65->192.168.1.95
Subnet4: 192.168.1.96           192.168.1.97->192.168.1.127 
Subnet5: 192.168.1.128         192.168.1.129->192.168.1.159
Subnet6: 192.168.1.160         192.168.1.161->192.168.1.191 
Subnet7: 192.168.1.192         192.168.1.193->192.168.1.223
Subnet8: 192.168.1.224         192.168.1.225->192.168.1.254 

Is it now more clear?
try to practice with different class of ip.
For additional study: http://www.cisco.com/c/en/us/support/docs/ip/routing-information-protocol-rip/13788-3.html