Netopia Router PN Series - Manual (Page 245)

Understanding IP Addressing B-9
must use the mask issued by the ISP). This, however, is not a
problematic limitation for your small network.
The advantages to this situation is the greater ease and lower cost
of obtaining a subnet from an ISP rather than a full Class C address.
Distributing IP addresses
To set up a connection to the Internet, you may have obtained a
block of IP host addresses from an Internet service provider. When
configuring the Netopia Router, you gave one of those addresses to
its Ethernet port, leaving a number of addresses to distribute to
computers on your network.
There are two schemes for distributing the remaining IP addresses:
■ Manually give each computer an address
■ Let the Netopia Router automatically distribute the addresses
These two methods are not mutually exclusive; you can manually
issue some of the addresses while the rest are distributed by the
Netopia Router. Using the Router in this way allows it to function as
an address server.
One reason to use the Netopia Router as an address server is that
it takes less time than manually distributing the addresses. This is
particularly true if you have many addresses to distribute. You only
need to enter information once, rather than having to repeatedly
enter it on each host separately. This also reduces the potential for
misconfiguring hosts.
Another reason to use the Netopia Router as an address server is
that it will only distribute addresses to hosts that need to use them.
If there is a shortage of addresses, the address server will
automatically take an address away from a host that has stopped
using it and give it to a host that is requesting one. If you do not
possess enough addresses for every host on your network to have
one at all times, using address serving to distribute them is one
solution. However, this is not an efficient solution because a host
without an IP address will be forced to wait until a host with one is
turned off or gives up its IP address for some other reason.