Now, next we will going to see the steps regarding how to compute the broadcast address of a subnet
So again
The user input is nothing but the IP address and the mask value that is configured on one of the machines present in the subnet
In our example, we have taken such a machine as machine B
So using this as the user input, let us see how to compute the broadcast address of a subnet
So follow the following steps to calculate the broadcast address
In step 1 obtain the network ID
So in the previous lecture, I have already discussed how to calculate the network ID
So, the first step is to obtain the network ID of a subnet
In the second step find the M'. M' is nothing but it is a complement of mask value 24
So in the previous slide when the mask value was 24 you converted
Into binary representation such that the first 24 bits are all ones and the next 8 bits are all zeros
Right. Now you have to do something opposite that is you have to find the complement of the mask value
So the complement of the mask value is nothing but do the opposite
That is the first 24 bits or all zeros and the remaining 8 bits are all ones
so we call this as M'
Right
So you can see that the first 24 bits are all zeros and then remaining 8 bits are all ones
Now finally in the step 3 perform the logical or operation between the binary
result that you have obtained in step 1 and the step 2
So you obtain the following as the final result
Now finally convert each octet of this result
Which you have obtained in step 3 into its decimal equivalent
You will get 11.1.1.255/24
which is actually the network broadcast address of our subnet
So this is also fairly simple. just follow the steps 1 2 3 & 4 to obtain the broadcast address of a given subject
Right
So what does actually broadcast address means? we will discuss in detail the concept of broadcast address
But for now just assume that
whenever a packet with the destination IP address is equal to
broadcast address comes or lands in our subnet
All the machines present in a subnet, Will going to process and accept the packet
More precisely saying that the network layer of all the machines note the word
network layer of all the machines will going to accept the packet if the destination IP address
present in the packet is equal to the
broadcast address or
If the destination IP address and the packet is equal to the IP address of the receiving interface of a device.
In both the scenarios the device will going to
Process and receive the packet. So this is how we compute the network broadcast address