Given a netwok mask
For ex: 255.255.240.0
First identify the class to which it belongs:
Here in the example given, it belongs to class B
The network mask of class B is 255.255.0.0
So first 2 octets belongs to net id and last 2 octets belongs to host id.
Convert last two octets 240.0 to binary and its binary equivalent is 1 1 1 1 0 0 0 0. 0 0 0 0 0 0 0 0
since there are 4 ones's here
Number of subnets = 2^number of ones-2 = 2^4 - 2 = 14
Number of hosts = 2^number of zeros-2 = 2^12 - 2 = 4094
For ex: 255.255.240.0
First identify the class to which it belongs:
Here in the example given, it belongs to class B
The network mask of class B is 255.255.0.0
So first 2 octets belongs to net id and last 2 octets belongs to host id.
Convert last two octets 240.0 to binary and its binary equivalent is 1 1 1 1 0 0 0 0. 0 0 0 0 0 0 0 0
since there are 4 ones's here
Number of subnets = 2^number of ones-2 = 2^4 - 2 = 14
Number of hosts = 2^number of zeros-2 = 2^12 - 2 = 4094
