Answer
A class C subnet uses the first three octets of an IP address to designate the network ID, and the remaining octet for the designation of the Host ID.
Host ID | | ip address xxx.xxx.xxx.xxx | | | | | | Network ID
The first three bits of the first octet are always set to one one zero, 110 to indicate a Class C address therefore this leaves 21 bits to represent the Network ID. These 21 bits provide 2, 097,152 network addresses. The remaining 8 bits are used for the host ID and this provides 254 or (28)-2 hosts per network
Keywords:IP Address subnet class