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.

  1. Each site requires:
    • Site A: 64 hosts
    • Site B: 30 hosts
    • Site C: 14 hosts
    • Site D: 10 hosts
  2. 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: 2= 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: 2= 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: 2= 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: 2= 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.