HP-UX LAN Administrator's Guide (Feburary 2007)

DRAFT COPY Network Addressing
Variable-Length Subnet Addressing
Chapter 7 123
Example of Subnets with Variable-Length Subnet Masks
The following example shows four subnetworks within the 192.6.12 network along with the
netconf entries necessary to configure these subnetworks with variable-length subnet masks.
Note that there are four different subnet masks used in this network. Also note that the
subnet numbers in the network map correspond to the mirror image subnet numbers listed in
Table 7-7.
Figure 7-13 Network Map with Variable-Length Subnets
The subnet numbers shown below correspond to the subnets show in the network map in
Figure 7-13.
In this example of mirror image counting, the first subnet has 6 hosts (with space allocated for
a maximum of 6 hosts), the second subnet has 60 hosts (with space allocated for a maximum
of 62 hosts), the third subnet has 30 hosts (with space allocated for a maximum of 30 hosts),
and the fourth subnet has 14 hosts (with space allocated for a maximum of 16 hosts). Notice
how the range of numbers (129-135, 65-127,193-223, and 33-47) is spread out to allow room
for additional growth in each case.
A
C
192.6.12.64,
255.255.255.192
B
192.6.12.192,
255.255.255.224
D
Corporate Offices
Marketing Dept.
(Subnet 1) R & D Dept.
(Subnet 6)
Facility LAN
(Subnet 16)
Manufacturing Dept.
(Subnet 2)
lan1
192.6.12.64,
255.255.255.192
lan0
192.6.12.129,
255.255.255.248
lan1
192.6.12.193,
255.255.255.224
lan0
192.6.12.130,
255.255.255.248
192.6.12.132
255.255.255.248
(Gateway)
lan1
192.6.20.1
(network 192.6.20)
lan0
192.6.12.131,
255.255.255.248
lan1
192.6.12.33,
255.255.255.240
192.6.12.128,
255.255.255.248
192.6.12.32,
255.255.255.240
E
Networking LAN
(Subnet 17)
lan2
192.6.12.1
192.6.12.2.
lan1
255.255.255.128