Subnetting Implementation in Cisco Packet Tracer

Last Updated : 26 Jun, 2022

A subnet, or subnetwork, is a part of a larger network. Subnets are a logical part of an IP network into multiple, smaller network components. The Internet Protocol (IP) is the method for transmitting data from one computer to another over the internet network. Each computer, or host, on the internet, has at least one IP address as a unique identifier.

To learn about subnetting refer to Introduction to Subnetting.

Steps to Configure and Verify Three Router Connections in Cisco Packet Tracer:

Step 1: First, open the Cisco packet tracer desktop and select the devices given below:

S.NO	Device	Model-Name	Qty.
1.	PC	pc	6
2.	Switch	PT-Switch	3
3.	Router	PT-Router	3

IP Addressing Table for PCs

S.NO	Device	IPv4 Address	Subnet Mask	Default-Gateway
1.	pc0	192.168.1.2	255.255.255.0	192.168.1.1
2.	pc1	192.168.1.3	255.255.255.0	192.168.1.1
3.	pc2	192.168.2.2	255.255.255.0	192.168.2.1
4.	pc3	192.168.2.3	255.255.255.0	192.168.2.1
5.	pc4	192.168.3.2	255.255.255.0	192.168.3.1
6.	pc5	192.168.3.3	255.255.255.0	192.168.3.1

Then, create a network topology as shown below the image.
Use an Automatic connecting cable to connect the devices with others.

Step 2: Configure the PCs (hosts) with IPv4 address and Subnet Mask according to the IP addressing table given above.

To assign an IP address in PC0, click on PC0.
Then, go to desktop and then IP configuration and there you will IPv4 configuration.
Fill IPv4 address and subnet mask.

Assigning IP address using the ipconfig command.

Or we can also assign an IP address with the help of a command.
Go to the command terminal of the PC.
Then, type ipconfig <IPv4 address><subnet mask><default gateway>(if needed)

Example: ipconfig 192.168.1.2  255.255.255.0 192.168.1.1

Repeat the same procedure with other PCs to configure them thoroughly.

Step 3: Configure router with IP address and subnet mask.

IP Addressing Table Router

S.NO	Device	Interface	IPv4 Address	Subnet mask
1.	router0	FastEthernet0/0	192.168.1.1	255.255.255.0
1.	router0	Serial2/0	11.0.0.1	255.0.0.0
2.	router1	Serial 2/0	11.0.0.2	255.0.0.0
2.	router1	Serial 3/0	12.0.0.1	255.0.0.0
3.	router 3	FastEthernet0/0	192.168.3.1	255.255.255.0
3.	router 3	Serial2/0	12.0.0.2	255.0.0.0

To assign an IP address in router0, click on router0.
Then, go to config and then Interfaces.
Then, configure the IP address in FastEthernet and serial ports according to IP addressing Table.
Fill IPv4 address and subnet mask.

Repeat the same procedure with other routers to configure them thoroughly.

Step 4: After configuring all of the devices we need to assign the routes to the routers.

To assign static routes to the particular router:

First, click on router0 then Go to CLI.
Then type the commands and IP information given below.

CLI command : ip route <network id> <subnet mask><next hop>

Static Routes for Router0 are given below:

Router(config)#ip route 192.168.2.0 255.255.255.0 11.0.0.2
Router(config)#ip route 11.0.0.0 255.0.0.0 11.0.0.2
Router(config)#ip route 192.168.3.0 255.255.255.0 11.0.0.2
Router(config)#ip route 12.0.0.0 255.0.0.0 11.0.0.2

Static Routes for Router1 are given below:

Router(config)#ip route 192.168.1.0 255.255.255.0 11.0.0.1
Router(config)#ip route 11.0.0.0 255.0.0.0 11.0.0.1
Router(config)#ip route 192.168.3.0 255.255.255.0 12.0.0.2
Router(config)#ip route 12.0.0.0 255.0.0.0 12.0.0.2

Static Routes for Router2 are given below:

Router(config)#ip route 192.168.1.0 255.255.255.0 12.0.0.1
Router(config)#ip route 11.0.0.0 255.0.0.0 12.0.0.1
Router(config)#ip route 12.0.0.0 255.0.0.0 12.0.0.1
Router(config)#ip route 192.168.2.0 255.255.255.0 12.0.0.1

Step 5: Verifying the network by pinging the IP address of any PC. We will use the ping command to do so.

First, click on PC0 then Go to the command prompt
Then type ping <IP address of targeted node>
As we can see in the below image we are getting replies which means the connection is working very fine