IPv4 Subnetting 1
Topology

Tasks:
A company plans to deploy 4 new sites. The sites will use IPv4 and each site requires different number of hosts. Subnet the IPv4 address block: 192.168.1.0/24 into 4 subnets with different host requirements.
- Each site requires:
- Site A: 64 hosts
- Site B: 30 hosts
- Site C: 14 hosts
- Site D: 10 hosts
- Assign the first usable IP address to the R1's interface for each subnet.
Solution:
Task 1: Each
site requires:
- Site A: 64 hosts
- Site B: 30 hosts
- Site C: 14 hosts
- Site D: 10 hosts
Subnet Calculation
for Site A:
Site A requires 64
hosts, we need at least 64 usable IPs. A /26 subnet provides 62 usable hosts,
which isn't enough. Instead, we’ll use /25, which provides 126 usable hosts.
For this we need to borrow one bit from the host section, which means 8-1 = 7
bits in host section.
A /25 subnet
provides:
Subnet Mask: 255.255.255.128
Total IPs: 27 = 128 (7 = number of bits in the host part)
Usable IPs: 128 − 2 = 126 (one is the network address and the other is the
broadcast address)
Using a /25 subnet we get :
Subnet Address: 192.168.1.0/25
Broadcast Address: 192.168.1.127
Usable Range: 192.168.1.1 – 192.168.1.126
Subnet Calculation
for Site B:
Site B requires 30
hosts, we need at least 30 usable IPs. A /27 subnet provides 30 usable hosts,
For this we need to borrow three bits from the host section, which means 8-3 =
5 bits in host section. This subnet will begin from 192.168.1.128.
A /27 subnet
provides:
Subnet Mask: 255.255.255.192
Total IPs: 25 = 32
Usable IPs: 32 − 2 = 30
Using a /27 subnet we get :
Subnet Address: 192.168.1.128/27
Broadcast Address: 192.168.1.159
Usable Range: 192.168.1.129 – 192.168.1.158
Subnet Calculation
for Site C:
Site C requires 14
hosts, we need at least 14 usable IPs. A /28 subnet provides 14 usable hosts,
For this we need to borrow four bits from the host section, which means 8-4 = 4
bits in host section. This subnet will begin from 192.168.1.160.
A /28 subnet
provides:
Subnet Mask: 255.255.255.240
Total IPs: 24 = 16
Usable IPs: 16 − 2 = 14
Using a /28 subnet we get :
Subnet Address: 192.168.1.160/28
Broadcast Address: 192.168.1.175
Usable Range: 192.168.1.161 – 192.168.1.174
Subnet Calculation
for Site D:
Site D requires 10
hosts, we need at least 14 usable IPs. This means we need to use /28 subnet
length again.. This subnet will begin from 192.168.1.176.
A /28 subnet
provides:
Subnet Mask: 255.255.255.240
Total IPs: 24 = 16
Usable IPs: 16 − 2 = 14
Using a /28 subnet we get :
Subnet Address: 192.168.1.176/28
Broadcast Address: 192.168.1.191
Usable Range: 192.168.1.177 – 192.168.1.190
Task 2: Assign the
first usable IP address to the R1's interface for each subnet.
Assign the first
usable IP addresses of each subnet to the R1's interaces.
Site A:
R1# configure
terminal
R1(config)# interface f0/0
R1(config-if)# ip address 192.168.1.1 255.255.255.128
R1(config-if)# no shut
Site B:
R1(config)#
interface f1/0
R1(config-if)# ip address 192.168.1.129 255.255.255.224
R1(config-if)# no shut
Site C:
R1(config)#
interface f2/0
R1(config-if)# ip address 192.168.1.161 255.255.255.240
R1(config-if)# no shut
Site D:
R1(config)#
interface f3/0
R1(config-if)# ip address 192.168.1.177 255.255.255.240
R1(config-if)# no shut
Now exit
configuration mode and save the configuration.
R1(config-if)# end
R1# write memory
Packet Tracer File
Clicking this button will begin the download of a ZIP file. Inside the ZIP file, you'll find a Packet Tracer Activity (.pka) file, which will automatically track your progress as you configure the network.