I'm going to be honest with you here – you pretty much already carried out this task when we were looking at classful addresses. However, because we are moving away from default subnet masks, we need to look at the last step of the process in more detail.
I'm going to use the 13.45.89.1 IP address and the 255.255.255.192 subnet mask for this example. First, we will convert the host IP and subnet mask into binary, like we did previously:
Figure 11.18: Converting the host IP and subnet mask into binary
Then, we calculate the Network ID in binary using the AND calculation and convert it into decimal:
