Selecting An Appropriate Address Class; Reserved Ip Addresses - Novell NETWARE 6-DOCUMENTATION Manual

Selecting an Appropriate Address Class

Reserved IP Addresses

When selecting an IP address class, you must decide on both network numbers
and host address portions. Because the first 1, 2, or 3 bits of the IP address
determine how the entire address is to be interpreted and where the division
between the network address and host address portion is to occur, you should
know the consequences of your choice. When deciding on a network class,
you should consider the number of IP nodes to be supported on your network
and the number of networks you plan to configure.
For example, if you use Class C addresses (the first 3 bits of the IP address are
110 binary), then you are restricted to 254 nodes. However, the number of
nodes available can be altered by using subnets. Before selecting an IP address
class, see "Creating Subnets" on page
The IP addressing rules reserve the following types of IP addresses for special
purposes:
Network addresses—IP addresses in which the host portion is set to all
zeros. For example,129.47.0.0 is the network address (or network
number) for a Class B network. Network addresses identify networks
rather than nodes on a network. By convention, no node is ever assigned
a host portion consisting of all zeros.
Broadcast addresses—Addresses in which the host portion is set to all
ones. A packet with a broadcast address is destined for every node on the
network. By convention, no node is ever assigned a host portion
consisting of all ones.
Loopback addresses—Addresses that cause the protocol software to
return data without sending traffic across a network. Network address
127.0.0.0 and all host addresses on that network (for example, 127.0.0.1)
are reserved.
Multicast addresses—Addresses that are used to send packets to a group
of hosts or routers. They range from 224.0.0.1 to 239.255.255.255.
Reserved addresses—Addresses in which the network portion consists
of all zeros or all ones.
28.
Understanding
25