Network Architecture and Models | Generated by AI

Home PDF

Below is a detailed tutorial to help you learn the chapter on Network Architecture and Models, focusing on the OSI Reference Model, the TCP/IP Protocol Suite, their comparison, and the functions and responsibilities of layered architectures. This is tailored to a technical course like Computer Networks Technology (02141) in the Chinese Higher Education Self-Study Examination (自考) system. The tutorial is structured to be comprehensive, beginner-friendly, and aligned with the technical depth expected in such a course.


Step 1: Understand the Basics of Network Architecture

Before diving into the models, let’s establish why network architecture matters:


Step 2: Learn the OSI Reference Model (7 Layers)

The OSI (Open Systems Interconnection) Model is a theoretical framework with 7 layers. Each layer has a specific role in communication. Let’s break it down:

1. Physical Layer

3. Network Layer

4. Transport Layer

5. Session Layer

6. Presentation Layer

7. Application Layer

Tip: Memorize the layers in order (Physical → Application) using a mnemonic like “Please Do Not Throw Sausage Pizza Away.”


Step 3: Learn the TCP/IP Protocol Suite (4 Layers)

The TCP/IP Protocol Suite is a practical model used in real-world networks (e.g., the Internet). It has 4 layers, which map roughly to the OSI model.

2. Internet Layer

3. Transport Layer

4. Application Layer

Tip: Think of TCP/IP as a simplified, real-world version of OSI.


Step 4: Compare OSI and TCP/IP Models

Here’s how they stack up:

Aspect OSI Model TCP/IP Model
Number of Layers 7 4
Nature Theoretical, detailed Practical, implemented
Layer Mapping - Physical → Physical - Link → Physical + Data Link
  - Data Link →  
  - Network → Network - Internet → Network
  - Transport → Transport - Transport → Transport
  - Session/Presentation/Application → - Application → Session + Presentation + Application
Development Designed before protocols Protocols came first
Usage Teaching, reference Real-world (Internet)
Flexibility Rigid, distinct layers More flexible, overlapping

Key Insight: OSI is like a detailed textbook; TCP/IP is the working engine of the Internet.


Step 5: Understand Layered Architecture Functions and Responsibilities

Each layer has a specific job and interacts with layers above and below it:

Example Flow (Sending an Email):

  1. Application: You write an email (SMTP formats it).
  2. Presentation: Email text is encoded (e.g., UTF-8), maybe encrypted.
  3. Session: A connection to the mail server is established.
  4. Transport: TCP breaks the email into packets, ensures delivery.
  5. Network: IP routes packets to the server.
  6. Data Link: Ethernet frames the packets for the local network.
  7. Physical: Bits travel over Wi-Fi or cable.

Reverse happens at the receiver!


Step 6: Study Tips for 自考 (Self-Study Exam)

  1. Memorize Key Terms: Know layer names, functions, and examples (e.g., TCP = Transport, reliable).
  2. Draw Diagrams: Sketch OSI (7 layers) and TCP/IP (4 layers) side by side to visualize mapping.
  3. Practice Questions:
    • What’s the role of the Network layer in OSI?
    • How does TCP/IP’s Application layer differ from OSI’s?
    • Explain encapsulation with an example.
  4. Use Analogies: Relate layers to real life (e.g., Physical layer = roads, Transport layer = couriers).
  5. Review Protocols: Focus on common ones (IP, TCP, UDP, HTTP) and where they fit.

Step 7: Test Your Understanding

Answer these to check your grasp:

  1. What layer handles IP addressing? (Network/Internet)
  2. Which OSI layer encrypts data? (Presentation)
  3. How does TCP/IP’s Link layer relate to OSI? (Combines Physical + Data Link)
  4. Why is OSI not used directly in the Internet? (Too theoretical; TCP/IP is practical)

Additional Resources


This tutorial gives you a solid foundation for the chapter. Study each section, revisit tricky parts, and practice explaining concepts aloud (great for 自考 prep). Good luck! If you need clarification on any part, just ask!


Back 2025.03.22 Donate