CIDR - Each Supernet is treated as a single entity
Since supernet addressing is a fairly complex mechanism, the easiest way to understand it is to walk through the setup process.
Step 1 - Select a netmask for each supernet
Each supernet must have a netmask assigned to it. The netmask for an individual supernet can be, but does not have to be, the same as the netmask for any other supernet.
As in subnetting, a netmask creates a division between the network portion of an address and the host portion of an address. However, since the network you are defining is larger than a Class C network, the division you are creating is not in the fourth octet of the address. For this example, we’ll be creating supernets composed of fewer than 254 Class C net- works. So, their netmasks will actually be splitting up the third octet in their IP addresses.
