VLSM and CIDR - Routing Protocols and Concepts - page 286

Table 6-12 Network Address Space Assignment for Lab 6-4

Subnet Network Address

HQ LAN1 172.16.64.0/23

HQ LAN2 172.16.66.0/23

EAST LAN1 172.16.68.0/24

EAST LAN2 172.16.69.0/24

WEST LAN1 172.16.70.0/25

WEST LAN2 172.16.70.128/25

Link from HQ to EAST 172.16.71.4/30

Link from HQ to WEST 172.16.71.0/30

Link from HQ to ISP 209.165.201.0/30

Task 1: Determine the Summary Route for the HQ LANs

List the HQ LAN1 and LAN2 in binary format. Step 1.

LAN1: 10101100.00010000.01000000.00000000

LAN2: 10101100.00010000.01000010.00000000

Count the number of leftmost matching bits to determine the mask for the summary route. Step 2.

How many leftmost matching bits are present in the two networks? 22

1.

What is the subnet mask for the summary route in decimal format? 255.255.252.0 2.

Copy the matching bits and then add all 0s to determine the summarized network address.

Step 3.

What are the matching bits for the two networks? 10101100.00010000.010000 1.

Add 0s to make up the remainder of the network address in binary form.
10101100.00010000.01000000.00000000

2.

What is the network address for the summary route in decimal format? 172.16.64.0

3.

Task 2: Determine the Summary Route for the EAST LANs

List the EAST LAN1 and LAN2 in binary format. Step 1.

LAN1: 10101100.00010000.01000100.00000000

LAN2: 10101100.00010000.01000101.00000000

Count the number of leftmost matching bits to determine the mask for the summary route.

Step 2.

How many leftmost matching bits are present in the two networks? 23 1.

What is the subnet mask for the summary route in decimal format? 255.255.254.0 2.

Copy the matching bits and then add all 0s to determine the summarized network address.

Step 3.

What are the matching bits for the two networks? 10101100.00010000.0100010 1.