1.1.6 

The following are VLSM calculations for the LAN connections in Figure :

• Network address: 192.168.10.0
• The Perth router has to support 60 hosts. That means a minimum of six bits are needed in the host portion of the address. Six bits will yield 2⁶ – 2, or 62 possible host addresses. The LAN connection for the Perth router is assigned the 192.168.10.0/26 subnet.
• The Sydney and Singapore routers have to support 12 hosts each. That means a minimum of four bits are needed in the host portion of the address. Four bits will yield 2⁴ – 2, or 14 possible host addresses. The LAN connection for the Sydney router is assigned the 192.168.10.96/28 subnet and the LAN connection for the Singapore router is assigned the 192.168.10.112/28 subnet.
• The KL router has to support 28 hosts. That means a minimum of five bits are needed in the host portion of the address. Five bits will yield 2⁵ – 2, or 30 possible host addresses. The LAN connection for the KL router is assigned the 192.168.10.64/27 subnet.

The following are VLSM calculations for the point-to-point connections in Figure :

• Perth to KL

The connection from Perth to KL requires only two host addresses. That means a minimum of two bits are needed in the host portion of the address. Two bits will yield 2² – 2, or 2 possible host addresses. The Perth to KL connection is assigned the 192.168.10.128/30 subnet.

• Sydney to KL

The connection from Sydney to KL requires only two host addresses. That means a minimum of two bits are needed in the host portion of the address. Two bits will yield 2² – 2, or 2 possible host addresses. The Sydney to KL connection is assigned the 192.168.10.132/30 subnet.

• Singapore to KL

The connection from Singapore to KL requires only two host addresses. That means a minimum of two bits are needed in the host portion of the address. Two bits will yield 2² – 2, or 2 possible host addresses. The Singapore to KL connection is assigned the 192.168.10.136/30 subnet.

The following configuration is for the Singapore to KL point-to-point connection:

Singapore(config)#interface serial 0

Singapore(config-if)#ip address 192.168.10.137 255.255.255.252

KualaLumpur(config)#interface serial 1

KualaLumpur(config-if)#ip address 192.168.10.138 255.255.255.252

This page concludes this lesson. The next lesson will discuss RIP. The first page describes RIP v1