Installing and Administering LAN/9000 Software

168 Chapter6
Network Addressing
CIDR - Classless Inter-Domain Routing
255.255.254.0
To implement this feature, you must apply the supernet netmask to all
interfaces connected to the supernet using the ifconfig(1M) command.
This feature will allow all hosts on the supernet to communicate with all
other hosts on the supernet without standard routing.
In the example below, the hosts in two Class C networks, 192.6.12 and
192.6.13, are included in a larger supernet using the netmask option.
NOTE Since the gateway is itself a host on the supernet, it must support CIDR.
11 111 11 111 11 111 1 1100 000011111 000
11 000 00 011 00 000 1 1010 000000000 010
11 000 00 011 00 000 1 1000 000000000 000
overwrite value 1 in
network address
resulting in a supernet
address of 192.6.12.
Net
Mask
255 . 255 . 254 . 0
0 values in mask
AND
192 . 6 . 13 . 2
Internet
Address
Bit values
converted to
zero
Bit values unchanged
Convert
to
Super-
net
Address
192 . 6 . 12 . 2