router-switch-lan-

A two-department LAN connected via switches and a router using an IP address with full inter-network communication.

TITLE SECTION

Project title: Inter-Departmental LAN Connectivity using routers and switches
Author: Thato Maputla
Date: 24 February 2026

OVERVIEW

This project shows a network between 2 departments in a company using the network address (192.168.40.0). All the end-user devices are configured with appropriate IP addresses, subnet masks, and gateways. The departments each consist of 3 end-user devices connected through dedicated switches and a central router. This design ensures that devices within and across departments can communicate seamlessly.

OBJECTIVES

1. Implement subnetting to create 2 departmental subnets from a single network ID
2. Configure switches to communicate within the departments.
3. Configure the router to enable communication across the network.
4. Verify connectivity between all devices through simulation tools.

NETWORK TOPOLOGY (Extended star)

Devices used:

• 1 Router (central interconnection point)
• 1 Laptop (for one department)
• 2 Switches (one per department)
• 2 Printers (one per department)
• 3 PCs (2 in one department, 1 in another)

Logical design:
Each department is connected to its own switch. The switches are connected to the router, which routes traffic between the two subnets.

SUBNETTING

Provided network: 192.168.40.0
Number of subnets required: 2

//formula for calculating subnets:
//2^n = 2
//solving for n, we get: n = 1
//given n = 1; this will represent borrowed bits
//11111111.11111111.11111111.10000000
//255.255.255.128 = Subnet mask with block size of 128

First Subnet:
Subnet mask = 255.255.255.128
Network ID = 192.168.40.0
CIDR notation = 192.168.40.0/25
Valid host range = 192.168.40.1 -> 192.168.40.126
Broadcast ID = 192.168.40.127

Second Subnet:
Subnet mask = 255.255.255.128
Network ID = 192.168.40.128
CIDR notation = 192.168.40.128/25
Valid host range = 192.168.40.129 -> 192.168.40.254
Broadcast ID = 192.168.40.255

IP ADDRESSING SCHEME

1. HR Department (192.168.40.128/25)

• PC 0: IP address=192.168.40.130 ; Subnet mask=255.255.255.128 ; Default gateway=192.168.40.129
• Laptop0: IP address=192.168.40.131 ; Subnet mask=255.255.255.128 ; Default gateway=192.168.40.129
• Printer0: IP address=192.168.40.132 ; Subnet mask=255.255.255.128 ; Default gateway=192.168.40.129
• Router Interface gig0/1: IP address=192.168.40.129 ; Subnet mask=255.255.255.128

2. Tech Support (192.168.40.0/25)

• PC 1: IP address=192.168.40.2 ; Subnet mask=255.255.255.128 ; Default gateway=192.168.40.1
• PC 2: IP address=192.168.40.3 ; Subnet mask=255.255.255.128 ; Default gateway=192.168.40.1
• Printer1: IP address=192.168.40.4 ; Subnet mask=255.255.255.128 ; Default gateway=192.168.40.1
• Router Interface gig0/0: IP address=192.168.40.1 ; Subnet mask=255.255.255.128

NETWORK CONFIGURATION

HR Department (192.168.40.128/25)

• PC0: 192.168.40.130 / 255.255.255.128 / Gateway: 192.168.40.129
• Laptop0: 192.168.40.131 / 255.255.255.128 / Gateway: 192.168.40.129
• Printer0: 192.168.40.132 / 255.255.255.128 / Gateway: 192.168.40.129
• Router Gig0/1: 192.168.40.129 / 255.255.255.128

Tech Support (192.168.40.0/25)

• PC1: 192.168.40.2 / 255.255.255.128 / Gateway: 192.168.40.1
• PC2: 192.168.40.3 / 255.255.255.128 / Gateway: 192.168.40.1
• Printer1: 192.168.40.4 / 255.255.255.128 / Gateway: 192.168.40.1
• Router Gig0/0: 192.168.40.1 / 255.255.255.128

IP Addressing Scheme

Department	Device	IP Address	Subnet Mask	Default Gateway
HR Department (192.168.40.128/25)	PC0	192.168.40.130	255.255.255.128	192.168.40.129
	Laptop0	192.168.40.131	255.255.255.128	192.168.40.129
	Printer0	192.168.40.132	255.255.255.128	192.168.40.129
	Router Gig0/1	192.168.40.129	255.255.255.128	—
Tech Support (192.168.40.0/25)	PC1	192.168.40.2	255.255.255.128	192.168.40.1
	PC2	192.168.40.3	255.255.255.128	192.168.40.1
	Printer1	192.168.40.4	255.255.255.128	192.168.40.1
	Router Gig0/0	192.168.40.1	255.255.255.128	—

CLI CONFIGURATION (sanitized)

1. Router: Router> en
   Router# config t
   Router(config)# int range gig0/0-1
   Router(config-if-range)# no shutdown
   Router(config-if)# do wr
   Router(config-if)# exit
   Router(config)# int gig0/0
   Router(config-if)# ip address 192.168.2.1 255.255.255.128
   Router(config-if)# int gig0/1
   Router(config-if)# ip address 192.168.2.129 255.255.255.128
   Router(config-if)# do wr
   Router(config-if)# exit
   

2. Switches: Default configuration sufficient for this project

3. End devices: Manually assigned IP addresses, subnet masks, and gateways.

TESTING & VERIFICATION

Ping tests:
PC0 -> Laptop0 (same subnet)
PC0 -> Printer1 (different subnet, routed via router)
Laptop0 -> PC1 (cross-department communication)
Results: All tests were successful, indicating communication across departments.

CONCLUSION

This project demonstrated the fundamentals of LAN design and inter-departmental communication using Cisco Packet Tracer. Key skills practiced: subnetting & IP addressing, application of CIDR notation, router configuration, application of the OSI Model, switch setup, and connectivity testing. The design can be scaled further by adding more departments, VLANs, or advanced routing protocols.