ch03 IP Addressing.pdf - The Cisco Learning Network

32 Chapter 3: IP Addressing
EXERCISE 3-1
Planning IP Addressing Exercise
ON THE CD
These last few sections dealt with how to create an addressing scheme for a network. This
exercise will help reinforce these concepts, including the six steps that you should use to
come up with an appropriate subnet mask value and network, directed broadcast, and host
addresses.
1. You are given a Class C network (192.168.1.0) and you have 4 segments
in your network, where the largest segment has 50 hosts. What subnet mask
should you use and what is the layout of your addresses?
Performing the six steps, the subnet mask is 255.255.255.192 (/26), giving
you four network numbers: 192.168.1.0, 192.168.1.64, 192.168.1.128,
and 192.168.1.192. Each of these four networks has a total of 64 addresses,
where 62 of these can be used for host devices.
2. You are given a Class B network (172.16.0.0) and you have 490 segments
in your network, where the largest segment needs 112 host addresses. What
subnet mask should you use and what is the layout of your addresses?
Performing the six steps, the subnet mask is 255.255.255.128 (/25), giving
you 512 network numbers: 172.16.0.0, 172.16.0.128, 172.16.1.0, 172.16.1.128,
172.16.2.0, 172.16.2.128, and so on and so forth. Each of these 512 subnets
has 128 addresses, of which 126 of these can be used to assign addressing
information to host devices.
3. You are given a Class A network (10.0.0.0) and you have 9,000 segments
in your network, where the largest segment needs 560 host addresses. What
subnet mask should you use and what is the layout of your addresses?
Make sure that you
practice, practice, and do more practice
on exercises like the above when preparing
for your exam. I can’t stress this enough.
Performing the six steps, the subnet mask is
255.255.252.0 (/22), giving you 16,384 network
numbers: 10.0.0.0, 10.0.4.0, 10.0.8.0, 10.0.12.0,
10.0.16.0, 10.0.20.0, 10.0.24.0, and so on and
so forth. Each of these 16,384 subnets has 1,024
addresses, of which 1,022 of these can be used
to assign addressing information to host devices.
Now you should be more comfortable with planning IP addressing. In the next
section, you will be presented with how to figure out whether an IP address is a
network, directed broadcast, or host address.