Help on finding the broadcast address for a given IP address and subnet mask.
To calculate broadcast address from a given IP address and subnet mask, follow the steps below.| Steps |
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| 1. For any octet if the subnet mask value is 255, copy the IP octet; if the subnet mask value is 0, put 255. |
| 2. For any octet, if the subnet mask is neither 0 nor 255: (a) Calculate the jump = 256-subnet mask. (b) Check the integer multiples of jump and find THE smallest integer multiple of jump that is > IP value on that octet. Copy that specific (integer multiple-1) on that octet. |
| Example1:IP: 130.143.214.6 and Subnet mask: 255.255.0.0. After you finish step 1, The broadcast address is 130.143.255.255. |
| Example2:IP: 110.103.214.110 and Subnet mask: 255.255.255.240. After finishing step 1, you have 110.103.214.____. After finishing step 2.a), jump=16 for the 4th octet At step 2. b) the multiples of jump are 0, 16, 32, 48.......and the value to copy is (112-1)=111. The broadcast address becomes 110.103.214.111 |
| Example3:IP: 130.143.214.6 and Subnet mask: 255.255.192.0. After finishing step 1, you have 130.143.____.255 After finishing step 2.a), jump=64 for the 3rd octet At step 2. b) the multiples of jump are 0, 64, 128, 192, 256...and the value to copy is (256-1)=255. The broadcast address becomes 130.143.255.255 |