Little more on IP addresses (valid host IDs)

Now that we know about IP addresses. Let us take a look at following:

Network address:

All host bits turned off is the network address.

For example in a class A address- 10.16.1.1, the network address is 10.0.0.0

Broadcast address:

All host bits turned on is the broadcast address. In the above example, 10.255.255.255

Valid host IDs are the number between the network address and the broadcast address.

Class A address

The class A format is as follows:

network.node.node.node

For example, a class A address 

Network address: 10.0.0.0

Broadcast address: 10.255.255.255

valid hosts - 10.0.0.1 through 10.255.255.254

Class B address

The class A format is as follows:

network.network.node.node

For example, a class B address 

Network address: 172.16.0.0

Broadcast address: 172.16.255.255

valid hosts - 172.16.0.1 through 172.16.255.254

Class C address

The class C format is as follows:

network.network.network.node

For example, a class C address 

Network address: 192.168.100.0

Broadcast address: 192.168.100.255

valid hosts - 192.168.100.1 through 192.168.100.254

Trick:  to check for a valid host ID just remember all the host bits can't be all turned on or off at the same time.