Now
a days we have lots of subnet calculator available in Internet. But
learning subnetting is still a "must" for network engineers. The one and
only way to learn subnetting is "Subnetting Practice".
Before
learning subnetting you have to know some basic terms, like what is
network bits, host bits, what is subnet mask. There are many definitions
of these terms. But below I'll give some simple and short
definition/explanation of them.