RIPv1 and VLSM

The network above is subnetted using a Class C address block. In the network above, there are a total of 12 networks (6 LANs and 6 point-to-point WANs). The 255.255.255.240 (/28) subnet mask is used to support a maximum of 16 networks with 14 usable IP addresses on each LAN.

RIPv1 does not support VLSM information, so all networks must have the same subnet mask.

This sample setup shows that even RIP does not support VLSM, such networks can be setup when all subnets are using the same subnet mask.

Below shows the routing table on RT1:

RT1#sh ip route

     192.168.0.0/28 is subnetted, 12 subnets
C       192.168.0.0 is directly connected, FastEthernet0/0
C       192.168.0.16 is directly connected, Serial1/1
R       192.168.0.32 [120/1] via 192.168.0.18, 00:00:01, Serial1/1
R       192.168.0.48 [120/1] via 192.168.0.18, 00:00:01, Serial1/1
R       192.168.0.64 [120/2] via 192.168.0.18, 00:00:01, Serial1/1
C       192.168.0.80 is directly connected, Serial1/0
R       192.168.0.96 [120/2] via 192.168.0.18, 00:00:01, Serial1/1
R       192.168.0.112 [120/1] via 192.168.0.82, 00:00:12, Serial1/0
R       192.168.0.128 [120/1] via 192.168.0.82, 00:00:12, Serial1/0
R       192.168.0.144 [120/2] via 192.168.0.82, 00:00:13, Serial1/0
R       192.168.0.160 [120/2] via 192.168.0.82, 00:00:12, Serial1/0
R       192.168.0.176 [120/3] via 192.168.0.18, 00:00:01, Serial1/1
                      [120/3] via 192.168.0.82, 00:00:12, Serial1/0
RT1#