Network Address And Broadcast Address

Network Address:

You cannot use first and last address of a network as host address. Network Address is the first address of a network. For example, if 10.0.0.0/8 is a network, 10.0.0.1 is network address.

Role of a network address

If you want to block or allow or want to adopt some routing rules against a good number of IPs, you've to add rules for each and every IP individually. It's a very hard task to maintain and incredibly time-consuming. Network address or ID solves this problem.It's a way to group a subnet. So, you just need to append your routing rules against a network address and all nodes those have assigned target network address will follow.

Broadcast Address:

The last IP of a network is the broadcast address.

Role of a broadcast address

You want to see if all the nodes under a router or subnet are linked or pingable or reachable. One way of doing is by pinging individual nodes. But it's again a regular way of doing. Better you can assign a broadcast address to all the nodes under a subnet or router, then you can just ping that broadcast address and get the status of every nodes under that broadcast address.