Effects of Partial Masking
Notice how important the subnet mask is in determining the logical subdivision of the network.
If the subnet mask in the figure below was 255.255.255.0 instead of 255.255.255.224, the broadcast address would not be 199.192.65.63. Instead, 199.192.65.255 would be the correct broadcast address.
Figure 3-12 Broadcasts on partially masked octets