IP Addressing
As with any other network-layer protocol, the IP addressing scheme is integral to the process of
routing IP datagrams through an internetwork. Each IP address has specific components and follows
a basic format. These IP addresses can be subdivided and used to create addresses for subnetworks,
as discussed in more detail later in this chapter.
Each host on a TCP/IP network is assigned a unique 32-bit logical address that is divided into two
main parts: the network number and the host number. The network number identifies a network and
must be assigned by the Internet Network Information Center (InterNIC) if the network is to be part
of the Internet. An Internet Service Provider (ISP) can obtain blocks of network addresses from the
InterNIC and can itself assign address space as necessary. The host number identifies a host on a
network and is assigned by the local network administrator.