You can define as many IP ranges as you need. An IP range has
start-limit. Here are some IP ranges for
different network types.
This defines the first 21 IP numbers of the class C network 192.168.1.0.
This defines a huge range in a class B network. Note that this notation won't be used much. This kind of network is often split into several physical networks, and IP numbers are allocated to each one. This is one place where the "IP range definitions" system is very useful.