Sandiah Notes

The IP Address and Classes
Hosts and networks
IP addressing is based on the concept of hosts and networks. A host is
essentially anything on the network that is capable of receiving and transmitting
IP packets on the network, such as a workstation or a router. It is not to be
confused with a server: servers and client workstations are all IP hosts.
The hosts are connected together by one or more networks. The IP address of
any host consists of its network address plus its own host address on the
network. IP addressing, unlike, say, IPX addressing, uses one address
containing both network and host address. How much of the address is used for
the network portion and how much for the host portion varies from network to
network.
IP addressing
An IP address is 32 bits wide, and as discussed, it is composed of two parts: the
network number, and the host number [1, 2, 3]. By convention, it is expressed
as four decimal numbers separated by periods, such as "200.1.2.3" representing
the decimal value of each of the four bytes. Valid addresses thus range from
0.0.0.0 to 255.255.255.255, a total of about 4.3 billion addresses. The first few
bits of the address indicate the Class that the address belongs to:
The bits are labeled in network order, so that the first bit is bit 0 and the last is bit
31, reading from left to right. Class D addresses are multicast, and Class E are