Classed or Classic IP Addresses

Classic TCP/IP Addressing architecture divides all possible IP addresses into classes based on the most significant bits of the address. The class determines what part of the address designates the network and what part designates the host. The three main address classes are Class A, Class B, and Class C. Class A addresses have a binary Zero (0) as the most significant bit of the address. The address range is from 0.0.0.0 to 127.255.255.255. The network portion is the most significant byte of the address, and the host portion is the three byte remainder. Class A network addresses are intended for networks that have more than 65,534 hosts on a single network. Class B addresses have binary One Zero (10) as the most significant two bits of the address. The address range is from 128.0.0.0 to 191.255.255.255. The network portion is the most significant two bytes of the address, and the host portion is the two byte remainder. Class B network addresses are intended for networks that have from 255 to 65,534 hosts on a single network. Class C addresses have binary One One Zero (110) as the most significant three bits of the address. The address range is from 192.0.0.0 to 223.255.255.255. The network portion is the most significant three bytes of the address, and the host is the one byte remainder. Class C network addresses are intended for networks that have fewer than 255 hosts on a single network. Addresses that have binary One One One (111) as the most significant three bits of the address are designated Class D or Class E addresses. These are reserved for Multi-cast and other special applications.