Internetworking: Classfull IP Addressing
Identification of class
- Class A 1 - 126
- /8 Prefixes -- 8-bit network-prefix with the highest order bit set to 0 and a seven-bit network number, followed by a 24-bit host-number.
- Class B 128 - 191
- /16 Prefixes -- Each Class B network address has a 16-bit network-prefix with the two highest order bits set to 1-0 and a 14-bit network number, followed by a 16-bit host-number.
- Class C 192 - 223
- /24 -- Prefixes Each Class C network address has a 24-bit network-prefix with the three highest order bits set to 1-1-0 and a 21-bit network number, followed by an 8-bit host-number.