Chapter 1: Network Models

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📘 Big Picture Summary

This chapter explains how devices communicate across networks using models that provide structure and rules for data transmission.

The two primary models are:

• OSI Model — Theoretical 7-layer model for understanding networking communication.
• TCP/IP Model — Practical 4-layer model used in real-world networking.

Understanding these models is crucial for troubleshooting, design, and real-life networking skills.

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🌳 Explore Deeper (Topics in this Chapter)

Network Models Introduction

• Network Models Overview → What is a model, why it exists, and basic concepts.

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OSI Model → The 7 Layers

• OSI Model Overview
  • Layer 7: Application Layer
  • Layer 6: Presentation Layer
  • Layer 5: Session Layer
  • Layer 4: Transport Layer
  • Layer 3: Network Layer
  • Layer 2: Data Link Layer
  • Layer 1: Physical Layer

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TCP/IP Model → The 4 Layers

• TCP/IP Model Overview
  • Application Layer
  • Transport Layer
  • Internet Layer
  • Network Interface (Link Layer)

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Encapsulation Process

• Encapsulation Explained → Wrapping data at each layer for transmission.

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Protocol Data Units (PDU)

• PDU at Each Layer → Matching layers with correct unit names.

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OSI vs TCP/IP Comparison

• OSI vs TCP-IP Comparison Table

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Protocols and Devices at Each Layer

• Protocols and Devices Per Layer → Real-world usage examples.

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📊 Visual Aids

• OSI Layer Diagram
• Encapsulation Flow Diagram
• PDU Flow Table

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🧪 Labs and Practice

• Lab Exercise 1.01: Network Hardware and Software
• Lab Exercise 1.02: netstat, ping, and tracert
• Lab Exercise 1.03: The OSI Model
• Lab Exercise 1.04: OSI Model Presentation -Lab Exercise 1.05: Networking (in Another Sense) and Staying Current with Industry

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📝 Practice Questions

1. List the seven OSI layers in order from top to bottom.
2. What is the main purpose of the OSI Model?
3. How many layers are in the TCP/IP Model?
4. What is encapsulation in networking?Describe the process from App to Physical.
5. What layer uses the term 'Packet'?
6. Which model is most used today?
7. What are two reasons the TCP/IP model is more common than OSI in real networks?
8. Compare TCP/IP layers to OSI layers. Which OSI layers are combined in the TCP/IP model?
9. What command do you use to view active connections? To test IP reachability?

(Answers in related pages)

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🔁 Related Terms

• MAC Address
• IP Address
• TCP
• UDP
• Switch
• Router

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