Subnets And Using A Subnet Mask - 3Com SuperStack 3 4900 SX Getting Started Manual

Subnets and Using a
Subnet Mask
The IP address can be split into two parts:
The first part ('192.168' in the example) identifies the network on
which the device resides.
The second part ('100.8' in the example) identifies the device within
the network.
If your network is internal to your organization only, you may use any
arbitrary IP address. We suggest you use addresses in the series
192.168.100.X (where X is a number between 1 and 254) with a subnet
mask 255.255.255.0. If you are using SLIP, use the default SLIP address of
192.168.101.1 with a subnet mask of 255.255.255.0.
These suggested IP addresses are part of a group of IP addresses that
have been set aside specially for use "in house" only.
CAUTION: If your network has a connection to the external IP network,
you must apply for a registered IP address. This registration system
ensures that every IP address used is unique; if you do not have a
registered IP address, you may be using an identical address to someone
else and your network will not operate correctly.
Obtaining a Registered IP Address
InterNIC Registration Services is the organization responsible for
supplying registered IP addresses. The following contact information is
correct at time of publication:
World Wide Web site: http://www.internic.net
You can divide your IP network into sub-networks also known as subnets.
Support for subnets is important because the number of bits assigned to
the device part of an IP address limits the number of devices that may be
addressed on any given network. For example, a Class C address is
restricted to 254 devices.
If you have a small network (less than 254 devices), you may decide not
to have multiple subnets.
Managing a Switch Over the Network 31