BranchLink Network Enterprise

Enterprise Network Design Using VLAN, OSPF, DHCP & Layer 3 Switching

📁 Project Overview

BranchLink Network Enterprise is a robust and scalable enterprise network simulation built using Cisco Packet Tracer. The project features two branch offices, each designed with VLAN segmentation, Inter-VLAN Routing, DHCP for dynamic IP assignment, and OSPF for dynamic routing between routers. Switch port configuration and trunking are applied to ensure proper VLAN propagation across access switches.

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🧱 Network Topology Summary

• 2 Branch Offices connected via routers
• 2 Multilayer Switches (MLSW1 & MLSW2) handling Inter-VLAN Routing
• 2 ISR Routers (R1 & R2) running OSPF for dynamic routing
• 8 Access Switches
• 16 PCs, dynamically assigned IPs via DHCP
• OSPF Area 0 for router communication
• VLANs with Trunk Links between switches

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🧩 VLAN Configuration

VLAN ID	Department	IP Subnet	Default Gateway	Color Code
10	HR	192.168.10.0/24	192.168.10.1	Light Cyan
20	IT	192.168.20.0/24	192.168.20.1	Bright Green
30	Sales	192.168.30.0/24	192.168.30.1	Light Purple
40	Marketing	192.168.40.0/24	192.168.40.1	Bright Yellow

VLANs are implemented on access and trunk ports to segment traffic and enforce security.

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🌐 IP Addressing Scheme

Device	Interface	IP Address	Subnet
R1	G0/0/0	192.168.1.1	/24
	G0/0/1	192.168.12.1	/24
R2	G0/0/0	192.168.2.1	/24
	G0/0/1	192.168.12.2	/24
MLSW1	SVI/VLAN Interface	192.168.1.2	/24
MLSW2	SVI/VLAN Interface	192.168.2.2	/24

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🔄 Dynamic Routing - OSPF

• OSPF is implemented between R1 and R2 over network 192.168.12.0/24
• Area: 0 (Backbone)
• Enables dynamic route advertisement between branch sites

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🔁 Inter-VLAN Routing

• Configured on Multilayer Switches (MLSW1 & MLSW2) using SVIs
• Ensures communication across VLANs within each branch

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🧠 DHCP Configuration

• DHCP services are configured on Multilayer Switches to assign dynamic IPs to PCs
• Each VLAN is assigned its own DHCP pool with proper IP range and default gateway

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🔌 Trunking and Switch Port Modes

• Trunk Ports: Enabled between access switches and MLSW for VLAN propagation
• Access Ports: Assigned to respective VLANs for end devices
• VLAN tags are preserved across switches via 802.1Q trunking

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⚙️ Key Features

• ✅ Logical Network Segmentation with VLANs
• ✅ Dynamic IP assignment using DHCP
• ✅ Inter-VLAN Routing via Layer 3 Switches
• ✅ OSPF Dynamic Routing across branch routers
• ✅ Trunk Port Configuration for VLAN propagation
• ✅ Static and Dynamic Routing Hybrid
• ✅ Fully Scalable Design for Enterprise Needs

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🔐 Security & Optimization

• VLANs isolate broadcast traffic
• Gateway-on-a-stick Inter-VLAN Routing eliminated using MLS for efficiency
• OSPF provides faster convergence and automatic route updates
• DHCP avoids manual IP configuration errors

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📂 File Structure

BranchLink_Network_Enterprise/
├── BranchLink Network Enterprise.pkt       # Cisco Packet Tracer file
├── README.md                    # Project documentation

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🖼️ Network Topology

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🔧 How to Test

1. Open the .pkt file in Cisco Packet Tracer.

2. Check VLANs: show vlan brief on switches.

3. Verify DHCP: PCs should receive IPs automatically.

4. Test Routing:

   • Ping between VLANs inside the same branch (Inter-VLAN Routing).
   • Ping across branches (Inter-Branch via OSPF).

5. View OSPF Tables: show ip route ospf or show ip protocols on routers.

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👤 Author

Designed by: Satyajeet Jena

Date: July 2025

Tool: Cisco Packet Tracer

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📝 License

Free to use for educational purposes. Not intended for commercial deployment.

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