How We Built a Scalable & Secure Topology for the Future
At IT Networks Services, we’ve designed and implemented a structured Layer 3 network topology that meets the demands of modern businesses. Our setup ensures high-speed performance, enhanced security, and seamless scalability—delivering reliable IT operations across all departments. Here’s a deep dive into our enterprise-grade network infrastructure and why it works.
Overview of Our Network Topology
We’ve adopted a Hybrid Star Topology that integrates:
- A multilayer core switch
- Access switches for edge connectivity
- A robust Cisco ASA firewall for security
- Layer 3 routing for VLAN segmentation
- Cisco and Fortinet devices for seamless performance
Key Network Hardware & Devices
| Device | Model / Options | Purpose |
|---|---|---|
| Core Switch | Cisco Catalyst 2960X, C9300, C9500 | Inter-VLAN Routing, Core Backbone |
| Access Switch | Cisco 2960X, C9200L Series | Edge Connectivity – PCs, Phones, WAPs |
| Firewall | Cisco ASA 5506-X, Fortinet 100F, Palo Alto PA-1410 | Secure traffic filtering, NAT, Intrusion Prevention |
| Router | Edge Router with public IPs | ISP Connectivity, Traffic Management |
Layer 3 VLAN Segmentation
We implemented VLANs to isolate traffic, boost performance, and strengthen security.
VLAN Subnet Table
| VLAN | Purpose | Subnet |
|---|
| 10 | Office PCs | 192.168.10.0/24 |
| 20 | IP Phones | 192.168.20.0/24 |
| 30 | Wireless APs | 192.168.30.0/24 |
Floor-wise VLAN Distribution
| Floor | VLAN 10 (PCs) | VLAN 20 (Cameras) | VLAN 30 (WAPs) |
|---|---|---|---|
| Ground Floor | 20 PCs | 4 Cameras | 3 Access Points |
| First Floor | 40 PCs | 6 Cameras | 5 Access Points |
| Second Floor | 40 PCs | 6 Cameras | 5 Access Points |
Security Architecture
Our network security is layered with firewalls, VLAN isolation, and NAT policies:
- Segmentation: VLAN isolation restricts lateral movement in case of a security breach.
- Firewall Filtering: All internal traffic is filtered before exiting to the internet.
- No Direct Routing: Server VLANs cannot access the internet directly.
- NAT Configuration: Private IPs are translated to public ones behind the firewall.
Cable Management & Connection Types
| Connection | Cable Type | Reason |
|---|---|---|
| Switch ↔ PC/Server | Straight-through | Different device types |
| Switch ↔ Firewall | Straight-through | Different device types |
| Router ↔ Firewall | Straight-through | Different device types |
| Switch ↔ Switch | Crossover | Same device type (uplinks) |
Simulation & Testing Before Deployment
We used Cisco Packet Tracer for pre-deployment testing to validate:
- VLAN and trunking configuration
- Inter-VLAN routing performance
- Firewall NAT and ACL policies
- Ping tests across VLANs and to public internet
This ensured zero errors at deployment and a smooth go-live.
Challenges We Solved
| Challenge | Solution |
|---|---|
| Redundancy | Trunk uplinks between switches to avoid single points of failure |
| IP Conflicts | Static DHCP reservations for servers |
| Future Scalability | VLAN modular design makes it easy to add departments or devices |
What’s Next at IT Networks Services?
To improve our enterprise network further, we’re planning to:
- Integrate VLAN-tagged WAPs for seamless and secure mobility
- Deploy SNMP monitoring systems for real-time alerts and analytics
- Add a secondary firewall in HA mode to ensure 100% uptime and better fault tolerance
Why This Topology Works
By leveraging Cisco Layer 3 switching, enterprise-grade firewalls, and modular VLAN design, we’ve built a future-ready infrastructure that:
- Boosts performance across all departments
- Enhances cybersecurity resilience
- Supports business expansion
- Reduces downtime and maintenance overhead
Cisco and Fortinet Equipment Used
| Device Type | Model Examples | Purpose |
|---|---|---|
| Switch (Core) | Cisco C9300-48P, C9500-24Y4C | High-speed core switching |
| Switch (Access) | Cisco C2960X-24PS, C9200L-24P-4X-E | Connectivity for end devices |
| Firewall | Cisco ASA 5506-X, Firepower 1140, FortiGate 100F, Palo Alto PA-1410, Sophos XGS2100 | Network perimeter security |
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Conclusion
With a scalable, secure, and intelligent network backbone, IT Networks Services has built a robust digital environment that empowers business operations across all levels. By integrating Cisco’s best practices, simulating every aspect, and deploying with precision, we’ve laid the groundwork for a future-proof enterprise infrastructure.
Need help building your own enterprise network? Get in touch with IT Networks Services to discover the best switches, firewalls, and network design tailored to your business goals.