Historic Ip Address Classes - Novell NETWARE 6-DOCUMENTATION Manual

Historic IP Address Classes

Class A Addresses
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NetWare TCP/IP Administration Guide
The addresses for all the nodes on the network must meet the following
criteria:
All addresses within a network must use the same prefix. For example,
any node on network 129.47 must have an address in the form 129.47.x.x.
Each node must have a unique IP address.
Each 4-byte IP address is divided into two parts:
A network portion, which identifies the network
A host portion, which identifies the node
IP addresses are differentiated into three classes, based on the two most
significant bits of the first byte. This is done so that routers can efficiently
extract the network portion of the address.
This division can occur at any one of three locations within the 32-bit address.
These divisions correspond to the three IP address classes: Class A, Class B,
and Class C. Regardless of address class, all nodes on any single network
share the same network portion; each node has a unique host portion.
A Class A IP address consists of a 1-byte network portion followed by a 3-byte
host portion, as shown in
network portion is always set to 0. Thus, within an internetwork, there can be
a total of 126 Class A networks (1 through 126), with more than 16 million
nodes in each (networks 0 and 127 are reserved).
The format of a Class A address is as follows:
0nnnnnnn.hhhhhhhh.hhhhhhhh.hhhhhhhh
where n represents the network address and h represents the host address.
Class A addresses contain 7 bits of network address and 24 bits of host
address.
Figure 6 on page 23. The highest-order bit of the