Note
This repository contains real world inspired network design challenges focused on developing infrastructure planning and design skills using Cisco Packet Tracer.
The primary goal is not configuration.
The goal is learning how to think like a network engineer before touching the CLI.
Every challenge begins with a business or technical requirement.
Your task is to determine:
- Architecture
- Device Placement
- Cable Selection
- Distance Limitations
- Interface Planning
- Connectivity Documentation
- Redundancy Requirements
- Physical Topology
then start by drawing on a notebook.
| Difficulty | Challenge | Scenario | Link |
|---|---|---|---|
| 🟢 Level 1 | Challenge 01 | Kalam Hospital Infrastructure | Open |
- Physical Network Design
- Infrastructure Planning
- Building-to-Building Connectivity
- Network Architecture Selection
- Distance-Based Cable Selection
- Core and Access Layer Design
- Documentation Practices
- Redundancy Planning
- Packet Tracer Implementation
- VLAN Configuration
- OSPF
- EIGRP
- BGP
- ACL Configuration
- Firewall Rules
- SD-WAN
- MPLS
- Automation
Those topics are valuable, but they are intentionally outside the scope of these exercises.
| Cable Type | Typical Maximum Distance | Common Use Cases |
|---|---|---|
| Cat5e | 100m | PCs, Printers, Access Switches |
| Cat6 | 100m | Modern LAN Deployments |
| Cat6A | 100m | 10 Gigabit Ethernet |
| Multi-Mode Fiber (MMF) | Up to ~550m | Building-to-Building Connectivity |
| Single-Mode Fiber (SMF) | Several Kilometers | Campus Networks, ISP Links |
| Coaxial | ISP Dependent | Cable Internet Delivery |
| Interface | Speed | Typical Usage |
|---|---|---|
| FE (FastEthernet) | 100 Mbps | Legacy PCs, Printers |
| GE (GigabitEthernet) | 1 Gbps | Modern End Devices, Uplinks |
| 10GE | 10 Gbps | Servers, Core Uplinks |
| SFP | Depends on Module | Fiber Connectivity |
| SFP+ | 10 Gbps | High-Speed Fiber Links |
| QSFP | 40/100 Gbps | Data Centers |
| Link Speed | Approx Real World Throughput | Typical Medium |
|---|---|---|
| 10 Mbps | ~1 MB/s | Cat5e |
| 100 Mbps | ~10 MB/s | Cat5e / Cat6 |
| 1 Gbps | ~100 MB/s | Cat5e / Cat6 |
| 2.5 Gbps | ~250 MB/s | Cat5e / Cat6 |
| 10 Gbps | ~1000 MB/s | Cat6A / Fiber |
| 40 Gbps | ~4000 MB/s | Fiber |
| 100 Gbps | ~10000 MB/s | Fiber |
| Architecture | Typical Size | When To Use |
|---|---|---|
| Flat Network | Very Small | Home Labs, Small Shops, Under 20 Devices |
| 2-Tier (Collapsed Core) | Small to Medium | Clinics, Schools, Offices, Small Campuses |
| 3-Tier | Medium to Large | Universities, Enterprises, Large Campuses |
| Spine-Leaf | Data Centers | East-West Traffic, Server Farms, Virtualization Environments |
| Situation | Recommended Design |
|---|---|
| Single Building | Access Switch → Router |
| Small Office | Access Switch → Core Switch |
| Multiple Buildings | Access Switches → Core Switch |
| Building Distance >100m | Fiber Uplink |
| High Bandwidth Server | Gigabit or Fiber Uplink |
| Critical Business Environment | Redundant Core |
| Critical Building Link | Dual Fiber Uplink |
| Internet Required | ISP → Firewall → Router/Core |
Before opening Packet Tracer, ask yourself :
- How many buildings exist?
- How many users exist?
- Where is the server located?
- Where does internet enter the network?
- Are any distances above 100m?
- Is fiber required?
- What architecture should be used?
- Are there any single points of failure?
- Is redundancy required?
- How will everything be documented?
start by drawing stuffs in a physical notebook and then packet tracer.
Before opening Packet Tracer.
Before drawing.
Before placing a single device.
Read the scenario and start asking questions.
The goal is to understand the problem before attempting to solve it.
Ask:
- How many users exist?
- How many buildings exist?
- How many departments exist?
- How far apart are the buildings?
- Are servers involved?
- Will the network need future expansion?
These answers help determine the architecture.
Few Devices + Single Building
↓
Flat Network
Multiple Buildings + Small/Medium Environment
↓
2-Tier Architecture
Large Campus + Multiple Departments
↓
3-Tier Architecture
Data Center Environment
↓
Spine-Leaf
At this stage, do NOT draw anything.
Simply decide which architecture is appropriate.
Use the Architecture Reference Table if needed.
Now look at the distances.
Ask:
- Is every device inside one building?
- Are buildings connected together?
- What is the longest cable run?
Use the Cable Selection Guide.
Distance ≤ 100m
↓
Cat6
Distance > 100m
↓
Fiber
Building-to-Building
↓
Fiber Preferred
High Bandwidth Requirement
↓
Fiber Strongly Recommended
At this stage, identify every connection that requires:
- Cat6
- Cat6A
- Multi-Mode Fiber
- Single-Mode Fiber
Do not draw yet.
Now ask:
- Can the organization tolerate downtime?
- Is this a hospital?
- Is this a school?
- Is this a retail store?
- Is this a factory?
- Is this a data center?
Not every network needs redundancy.
Small Office
↓
Single Uplink
School
↓
Usually Single Uplink
Hospital
↓
Redundancy Recommended
Factory
↓
Redundancy Recommended
Critical Infrastructure
↓
Full Redundancy
This step determines whether you need:
- Dual Core Switches
- Dual Fiber Links
- Dual Internet Paths
Now begin identifying where devices belong.
Ask:
Usually:
ISP
↓
Firewall
↓
Router
↓
Core Switch
Usually:
Core Layer
because every building must reach them.
Usually:
Access Layer
through access switches.
Usually:
Access Layer Switches
close to the users.
start drawing, imagine a packet.
Example:
PC
↓
Access Switch
↓
Core Switch
↓
Firewall
↓
Internet
Now ask:
- Does the packet path make sense?
- Is there an unnecessary hop?
- Is traffic crossing buildings unnecessarily?
- Are servers located logically?
If the packet path feels messy, the design probably is too.
Only now should you actually begin drawing.
Start with:
Internet
Then:
Firewall
Then:
Router
Then:
Core
Then:
Access Switches
Finally:
Users
Servers
Printers
Access Points
Focus on structure.
Ignore port numbers for now.
After the drawing is complete:
Label:
GE0/0
GE0/1
FE0/1
FE0/2
SFP1
SFP2
Use the Interface Reference Table.
Typical guideline:
PCs
↓
FastEthernet or Gigabit
Access → Core
↓
Gigabit
Building → Building
↓
SFP / Fiber
Core → Core
↓
Gigabit or Fiber
Now create the connectivity table.
Document:
- Source Device
- Source Port
- Cable Type
- Destination Device
- Destination Port
- Purpose
If someone else can rebuild the network using only your documentation, the documentation is good.
Ask:
If this switch dies:
What breaks?
If this cable breaks:
What breaks?
If this building loses connectivity:
Can traffic reroute?
If the company doubles in size:
Can I add another switch?
Can I add another building?
Can I add another server?
Are any links bottlenecks?
Should fiber be used?
Should uplinks be upgraded?
Never start Packet Tracer first.
Use this order:
Read Scenario
↓
Determine Scale
↓
Determine Distance Constraints
↓
Determine Criticality
↓
Choose Architecture
↓
Choose Cables
↓
Place Devices
↓
Imagine Packet Flow
↓
Draw On Paper
↓
Assign Interfaces
↓
Create Documentation
↓
Build In Packet Tracer
↓
Review Design
Packet Tracer should be the final step, not the first step.
Contributions are welcome.
To keep the repository useful for beginners and intermediate learners, all submitted challenges should follow these rules.
- Physical Topology Design
- Schools
- Hospitals
- Offices
- Warehouses
- Hotels
- Retail Stores
- Small Campuses
- Building-to-Building Connectivity
- Cable Selection
- Infrastructure Expansion
- Redundancy Planning
- VLAN Configuration Exercises
- Routing Protocol Labs
- Firewall Rule Challenges
- SD-WAN
- MPLS
- Cloud Infrastructure
- Enterprise Automation
- Vendor-Specific CLI Challenges
Every challenge should include:
- Scenario Description
- Distance Information
- Device Requirements
- User Requirements
- Architecture Decision
- Cable Selection Decision
- Packet Tracer Topology
- Connectivity Documentation
A challenge should be solvable using:
- Logic
- Networking Fundamentals
- Distance Calculations
- Infrastructure Planning
A challenge should NOT require:
- Memorizing Commands
- Vendor Certifications
- Advanced Routing Knowledge
The objective is helping learners build strong infrastructure design thinking.
Most networking problems are solved long before the first command is typed.
Good design makes configuration easier.
Bad design makes every future change harder.