📘 Network Diagram (OOAD / System Design View)
🔹 1. Definition
A Network Diagram is a graphical representation that shows how different computers, devices, and systems are connected and communicate with each other in a network.
👉 Simple idea:
It shows “who is connected to whom and how data flows between them.”
🔹 2. Purpose of Network Diagram ⭐
- Show system communication structure
- Understand data flow between devices
- Plan system architecture
- Help in network design and troubleshooting
- Useful in distributed systems
🔹 3. Key Components
🔸 3.1 Nodes (Devices)
Represents physical devices:
- Computer
- Server
- Router
- Printer
- Mobile device
🔸 3.2 Links (Connections)
Represents communication paths:
- Wired connection (LAN, cable)
- Wireless connection (Wi-Fi)
🔸 3.3 Data Flow
- Shows direction of communication
- Can be one-way or two-way
🔹 4. Types of Network Diagrams ⭐
🔸 4.1 Logical Network Diagram
- Shows how data flows
- Focus on communication structure
- Ignores physical hardware details
👉 Example:
- Client → Server → Database
🔸 4.2 Physical Network Diagram
- Shows actual hardware setup
- Includes servers, routers, cables
🔹 5. Basic Network Diagram Example
[Client PC] → [Web Server] → [Database Server]
👉 Flow:
- Client sends request
- Server processes request
- Database stores/retrieves data
🔹 6. Real-Life Example (Online Shopping System)
User Mobile → Internet → App Server → Database Server
🔹 7. Network Topologies (Common Structures)
🔸 7.1 Star Topology ⭐
- All devices connect to a central hub
PC
|
PC — Hub — PC
|
PC
🔸 7.2 Bus Topology
- All devices share one communication line
🔸 7.3 Ring Topology
- Devices connected in a circular loop
🔸 7.4 Mesh Topology
- Every device connected to every other device
🔹 8. Difference: Network Diagram vs Deployment Diagram ⭐
| Feature |
Network Diagram |
Deployment Diagram |
| Focus |
Communication flow |
Software deployment |
| Level |
Logical/physical network |
System architecture |
| Shows |
Devices + connections |
Nodes + software artifacts |
| Use |
Networking |
Software systems |
🔹 9. Advantages of Network Diagrams
- Easy to understand system communication
- Helps in network planning
- Useful for troubleshooting
- Improves system design clarity
- Supports distributed system design
🔹 10. Important Rules / Guidelines
- Clearly label all nodes and connections
- Avoid cluttered diagrams
- Show correct data flow direction
- Separate logical and physical views
- Keep diagram simple and readable
🔹 11. Where Network Diagrams are Used
- Internet systems
- Banking systems
- Cloud applications
- Distributed databases
- Client-server applications
🔹 12. Likely Exam Questions
- Define network diagram.
- What is the purpose of a network diagram?
- Explain logical vs physical network diagram.
- Draw a simple network diagram for online system.
- What are nodes and links?
- Explain star topology.
- Difference between network and deployment diagram.
- Where are network diagrams used?
- Explain mesh topology.
- Advantages of network diagrams.
🔹 13. Quick Revision Summary 🧠
Types:
- Logical (data flow)
- Physical (hardware setup)
👉 Trick to Remember:
"N = Nodes + Networks + Navigation of data"