Examples

# Example Topologies

NetSimWeb includes pre-built network topologies to help you learn networking concepts.

## Loading Examples

1. Click **File** → **Open Topology**
2. Navigate to the `examples/` directory
3. Select any `.json` file
4. The topology loads on the canvas

!!! tip "Drag and Drop"
    You can also drag and drop JSON topology files directly onto the canvas.

## Available Examples

### Simple Two PCs
**File:** `simple-two-pcs.json`  
**Difficulty:** Beginner

Two PCs connected through a switch. Perfect for learning basic ping and ARP.

[PC1] ----[Switch]---- [PC2]

**Try:** Ping from PC1 to PC2 and observe ARP resolution.

---

### VLAN Segmentation
**File:** `vlan-segmentation.json`  
**Difficulty:** Intermediate

Network with VLAN 10 (Sales) and VLAN 20 (Engineering) on one switch.

[Sales-PC1] ---+ +--- [Eng-PC1] VLAN 10 | | VLAN 20 +--[Switch]--+ VLAN 10 | | VLAN 20 [Sales-PC2] ---+ +--- [Eng-PC2]

**Try:** Ping within VLANs (works) vs between VLANs (blocked).

---

### Inter-VLAN Routing
**File:** `inter-vlan-routing.json`  
**Difficulty:** Intermediate

Layer 3 switch with SVIs enabling inter-VLAN routing.

SVI 10: 10.10.10.1 SVI 20: 10.20.20.1 | [L3 Switch] / \ VLAN 10 VLAN 20 | | [VLAN10-PCs] [VLAN20-PCs]

**Try:** Ping between VLANs - traffic routes through the SVIs.

---

### Trunk Links
**File:** `trunk-links.json`  
**Difficulty:** Intermediate

Two switches connected via 802.1Q trunk, VLANs spanning both.

[VLAN10-PC] --[SW1]===TRUNK===[SW2]-- [VLAN10-PC] [VLAN20-PC] --+ +-- [VLAN20-PC]

**Try:** Ping between same-VLAN PCs on different switches.

---

### Multi-Router Network
**File:** `multi-router-network.json`  
**Difficulty:** Advanced

Enterprise network with core router, two branches, and data center.

[Core-Router] / | \ [Branch1] [DC] [Branch2] | / \ | [SW] [Web][DB] [SW] / \ / \ [PC1][PC2] [PC1][PC2]

**Try:** Ping from Branch1-PC to Web-Server (multi-hop routing).

---

### Spanning Tree Protocol - Triangle
**File:** `stp-triangle.json`  
**Difficulty:** Intermediate

Three switches in a triangle with redundant links. STP prevents loops.

[SW1-Root] / \ / \ [SW2]----------[SW3] | ^ | [PC1] blocked [PC2]

**Try:** 
1. Open terminal on any switch, run `show spanning-tree`
2. Note SW1 is root (priority 4096)
3. Run `show stp interface` to see blocked port
4. Ping PC1 to PC2 - traffic flows through root

---

### DHCP Server
**File:** `dhcp-server.json`  
**Difficulty:** Beginner

Router as DHCP server with client PCs.

[DHCP-Router] | [Switch] / | \ [PC1][PC2][PC3] DHCP DHCP Static

**Try:** Request DHCP on clients to get IP addresses from the pool.

---

## Creating Your Own

1. Build your network in the simulator
2. Click **File** → **Save Topology**
3. Save as `.json` file

## JSON Structure

Topology files contain:

```json
{
  "name": "My Network",
  "description": "Description here",
  "devices": [...],
  "connections": [...]
}

See examples/README.md for complete JSON structure reference.

```