docs(notes): add computer networks introduction for 2025-03-22

Author: lzwjava

notes/2025-03-22-computer-networks-introduction-en.md

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+---
+title: Computer Networks - Introduction
+lang: en
+layout: post
+audio: false
+translated: false
+generated: true
+---
+
+Below, I’ll focus on the **Introduction to Computer Networks** chapter, likely the first section of the *Computer Networks Technology (02141)* course in the Guangdong self-study exam. I’ll provide key materials for learning, main points to grasp, example quiz questions, and study tips to help you prepare effectively before your exam.
+
+---
+
+### Main Points of "Introduction to Computer Networks"
+The introductory chapter typically lays the foundation for understanding computer networks. Here are the essential concepts to master:
+
+1. **Definition and Purpose**  
+   - A computer network is a set of interconnected devices (computers, phones, etc.) that share resources and exchange data.  
+   - Purpose: Enable communication, resource sharing (e.g., printers), and data access (e.g., internet).
+
+2. **Network Classifications**  
+   - **By Scale**:  
+     - LAN (Local Area Network): Small area (e.g., office, home).  
+     - WAN (Wide Area Network): Large area (e.g., internet).  
+     - MAN (Metropolitan Area Network): City-wide.  
+     - PAN (Personal Area Network): Personal devices (e.g., Bluetooth).  
+   - **By Connection**: Wired (e.g., Ethernet) vs. Wireless (e.g., Wi-Fi).
+
+3. **Network Topologies**  
+   - Physical or logical arrangement of devices:  
+     - **Star**: Central hub, easy to manage, fails if hub fails.  
+     - **Bus**: Single cable, simple but prone to collision.  
+     - **Ring**: Circular data flow, each device connected to next.  
+     - **Mesh**: Every device connected, reliable but complex.
+
+4. **Basic Components**  
+   - **Nodes/Devices**: Computers, routers, switches, etc.  
+   - **Transmission Media**: Cables (twisted pair, fiber), wireless (radio waves).  
+   - **Protocols**: Rules for communication (e.g., TCP/IP).
+
+5. **Network Applications**  
+   - Examples: Web browsing (HTTP), email (SMTP), file sharing (FTP).  
+   - Importance: Drives modern communication and business.
+
+---
+
+### Learning Materials
+Here are recommended resources to study the "Introduction to Computer Networks" chapter:
+
+1. **Textbooks**  
+   - *Computer Networks* by Andrew S. Tanenbaum (Chinese edition available in libraries or bookstores like Dangdang).  
+     - Focus: Chapter 1 covers basics like definitions, topologies, and types.  
+   - *Data Communications and Networking* by Behrouz A. Forouzan (widely used in China).  
+     - Focus: Early chapters on network models and intro concepts.  
+
+2. **Self-Study Exam Guides**  
+   - Look for Guangdong-specific 自考教材 (self-study textbooks) for course 02141, published by Higher Education Press or Peking University Press.  
+     - Available at local bookstores or online (e.g., JD.com, Taobao).  
+   - Check for "Computer Networks Technology" guides with past questions.
+
+3. **Online Resources**  
+   - **Khan Academy**: Free networking basics (search "Introduction to Networks").  
+   - **YouTube**: Channels like "PowerCert Animated Videos" or "CrashCourse Computer Science" (English, but clear visuals). Search "计算机网络入门" for Chinese videos.  
+   - **Cisco Networking Academy**: Free intro modules (cisco.com, search "Networking Essentials").  
+
+4. **Notes and Summaries**  
+   - Create a cheat sheet with definitions, topology diagrams, and examples (e.g., LAN in a school, WAN as the internet).  
+   - Use flashcards for terms like "protocol," "topology," and "LAN/WAN."
+
+---
+
+### Example Quiz Questions
+Here’s a sample quiz to test your understanding, with answers provided:
+
+#### Multiple Choice
+1. **What is the primary purpose of a computer network?**  
+   a) To store data locally  
+   b) To connect devices for resource sharing and communication  
+   c) To increase device speed  
+   d) To replace hardware  
+   - *Answer*: b) To connect devices for resource sharing and communication  
+
+2. **Which network type covers a small geographic area like an office?**  
+   a) WAN  
+   b) LAN  
+   c) MAN  
+   d) PAN  
+   - *Answer*: b) LAN  
+
+3. **In a star topology, what happens if the central hub fails?**  
+   a) Network continues normally  
+   b) Only one device loses connection  
+   c) Entire network fails  
+   d) Data reroutes automatically  
+   - *Answer*: c) Entire network fails  
+
+#### True/False
+4. **A bus topology uses a single shared cable for all devices.**  
+   - *Answer*: True  
+
+5. **WAN stands for Wireless Area Network.**  
+   - *Answer*: False (Wide Area Network)  
+
+#### Short Answer
+6. **Name two examples of network applications.**  
+   - *Answer*: Web browsing (HTTP), email (SMTP)  
+
+7. **List two advantages of a mesh topology.**  
+   - *Answer*: High reliability (multiple paths), fault tolerance (if one link fails, others work).  
+
+---
+
+### Study Tips Before the Exam
+1. **Focus on Key Concepts**  
+   - Memorize definitions (e.g., LAN vs. WAN) and topology pros/cons.  
+   - Draw topology diagrams (star, bus, etc.) to visualize connections.
+
+2. **Practice Questions**  
+   - Use past self-study exam papers (check Guangdong exam office or online forums like Baidu Tieba).  
+   - Time yourself: 5-10 minutes per set of 10 questions.
+
+3. **Understand, Don’t Just Memorize**  
+   - Example: Why is star topology common? (Easy to add devices, centralized control.)  
+   - Relate to real life: Your home Wi-Fi is a LAN!
+
+4. **Review Protocols Briefly**  
+   - Know that protocols (e.g., TCP/IP) are rules—details come later in the course, but the intro might mention them.
+
+5. **Rest and Revise**  
+   - Study 1-2 hours daily on this chapter, then review notes the day before the exam.  
+   - Sleep well—self-study exams like 02141 often test clear thinking.
+
+---
+
+### Quick Recap of Main Points
+- **What**: Networks connect devices to share data/resources.  
+- **Types**: LAN (small), WAN (large), MAN, PAN.  
+- **Topologies**: Star (central), Bus (shared), Ring (loop), Mesh (all connected).  
+- **Components**: Devices, media, protocols.  
+- **Applications**: Web, email, file sharing.
+
+Let me know if you want more quiz questions or help with another chapter! Good luck with your exam prep!