An address that enables transmission to every node in a local network. The address is the highest numeric value of the address format being used. An Ethernet broadcast address is all binary 1's. An IP broadcast address is the highest number in its class; for example, the broadcast address of a Class C 192.168.16.0 network is 192.168.16.255.
Subnet Broadcast Addresses
The broadcast address for a subnet must account for the part of the address that is reserved for the subnet. Using the above Class C example configured for six subnets would have a broadcast address of 192.168.16.31. It is derived as follows. For more on the Class C example, see
subnet mask. See
broadcast and
multicast.
Class C Mask for Six Subnets
255 255 255 224
11111111.11111111.11111111.11100000
Step 1
Invert the mask.
0 0 0 31
00000000.00000000.00000000.00011111
Step 2
OR the inverted mask with an IP
address in the subnet, such as
192.168.16.1.
192 168 16 1
11000000.10101000.00010000.00000001
00000000.00000000.00000000.00011111
-----------------------------------
11000000.10101000.00010000.00011111
192 168 16 31