How to Planning IP Address Step 5

14 May 2009

Step 5: Figure Out the Directed Broadcast Addresses

After figuring out all of your subnets, you next need to figure out what the directed broadcast address is for each subnet.

This is very simple. The directed broadcast of a subnet is one number less than the next network number.

Also, the broadcast address has all of its hosts bits set to binary 1s. Table as below shows our network numbers and directed broadcast addresses.

For the last table entry, the directed broadcast address will be the highest possible value in a byte: 255.

Network Addresses	Mathematics	Directed Broadcast Addresses
192.168.1.0	16-1	192.168.1.15
192.168.1.16	32-1	192.168.1.31
192.168.1.32	48-1	192.168.1.47
192.168.1.48	64-1	192.168.1.63
192.168.1.64	80-1	192.168.1.79
192.168.1.80	96-1	192.168.1.95
192.168.1.96	112-1	192.168.1.111
192.168.1.112	128-1	192.168.1.127
192.168.1.128	144-1	192.168.1.143
192.168.1.144	160-1	192.168.1.159
192.168.1.160	176-1	192.168.1.175
192.168.1.176	192-1	192.168.1.191
192.168.1.192	208-1	192.168.1.207
192.168.1.208	224-1	192.168.1.223
192.168.1.224	240-1	192.168.1.239
192.168.1.240		192.168.1.255

Next go to step 6 to planning your ip address here.