Introduction
This essay documents the planning, design, and analysis of a simulated company network for a small enterprise with two departments: Human Resources (HR) and Information Technology (IT). As a student in network engineering, I used Cisco Packet Tracer to build and test the network, incorporating concepts such as VLAN segmentation, switching, and routing. The purpose is to demonstrate understanding of local network structures, reference models like OSI, and practical skills in configuration and troubleshooting. Key elements include a physical and logical topology, IP planning, traffic simulation, and reflection on challenges, aligned with course objectives on data communication standards (Cisco Networking Academy, 2023).
Planning the Enterprise Network
In planning the network, I considered user needs: HR requires secure access for employee data handling, while IT needs robust connectivity for system maintenance. Separation of departments enhances security and reduces broadcast traffic, preventing HR users from accessing IT resources unintentionally. The physical structure involves two switches connected to a router, with at least two PCs per department. Logically, VLANs segment traffic: VLAN 10 for HR (192.168.10.0/24) and VLAN 20 for IT (192.168.20.0/24). This setup uses devices like Cisco 2960 switches and a 2911 router, motivated by scalability and cost-effectiveness for a small firm (Kurose and Ross, 2017). The default gateway, configured on the router (e.g., 192.168.10.1 for HR), enables inter-VLAN routing by directing traffic between networks at OSI Layer 3.
Network Design and VLAN Segmentation
Using Cisco Packet Tracer, I created the topology: Switch1 connects HR PCs (ports Fa0/1-2 to VLAN 10), Switch2 handles IT (ports Fa0/1-2 to VLAN 20), both linked to the router via trunk ports for VLAN tagging. Configurations included switchport mode access for access ports and switchport mode trunk for inter-switch links, ensuring tagged traffic. VLANs are used to logically separate broadcast domains, improving security and efficiency without additional hardware (Tanenbaum, 2011). Intra-VLAN pings succeeded (e.g., HR PC1 to PC2), but inter-VLAN required router configuration for routing, which I enabled to allow controlled communication.
Documentation and Traffic Simulation
The network map shows a star topology physically, with logical VLAN divisions. IP plan: HR PCs at 192.168.10.10-11, IT at 192.168.20.10-11. MAC addresses (simulated): HR PC1 00:0A:41:2B:3C:4D, etc. Router interfaces: GigabitEthernet0/0 for VLAN 10 subinterface. Tests confirmed intra-VLAN pings with <10ms latency, while inter-VLAN succeeded post-routing setup, verifying functionality.
Troubleshooting and OSI Model Analysis
I simulated a fault by assigning an IT PC to VLAN 10 incorrectly. Detection via failed pings; troubleshooting involved checking switchport configurations (Layer 2) and IP settings (Layer 3) using ‘show vlan brief’ commands, resolving by reassigning the port. This highlights systematic debugging. Linking to OSI: Physical cabling is Layer 1, MAC/VLANs Layer 2, IP/routing Layer 3, with ping testing Network layer connectivity (Forouzan, 2021).
Reflection
The hardest part was VLAN trunking configuration, teaching me routing’s role in inter-VLAN communication. Troubleshooting deepened network understanding by revealing configuration interdependencies. Documenting physical vs. logical designs is crucial for maintenance, and OSI aids in layered problem-solving.
Conclusion
This simulated network demonstrates effective use of VLANs, switching, and routing for departmental segmentation, supported by testing and OSI analysis. It underscores the importance of structured planning for secure, efficient networks, with implications for real-world enterprise scalability. Future work could include advanced services like DHCP.
References
- Cisco Networking Academy (2023) Introduction to Packet Tracer. Cisco Systems.
- Forouzan, B.A. (2021) Data Communications and Networking. McGraw-Hill Education.
- Kurose, J.F. and Ross, K.W. (2017) Computer Networking: A Top-Down Approach. Pearson.
- Tanenbaum, A.S. (2011) Computer Networks. Pearson.
