Day 3: Introduction to Computer Networks

Learning Objectives

• CSN-1.E: For fault-tolerant systems like the Internet: a. Describe the benefits of fault tolerance. b. Explain how a given system is fault-tolerant. c. Identify vulnerabilities to failure in a system.

Essential Questions

• What is a computer network and why are networks important?
• How do computers communicate with each other in a network?
• What are the different types of networks and their characteristics?

Materials Needed

• Presentation slides on network fundamentals
• Network diagram templates
• Paper, envelopes, and index cards for network simulation activity
• Concept map templates
• Exit ticket templates

Vocabulary

• Network
• Node
• Client
• Server
• Peer-to-peer
• LAN (Local Area Network)
• WAN (Wide Area Network)
• Bandwidth
• Protocol
• Topology
• IP address

Procedure (50 minutes)

Opening (8 minutes)

1. Review and Connection (3 minutes)

   • Review computing system layers from previous lesson
   • Connect to today's focus on how computing systems communicate through networks

2. Warm-up Activity (5 minutes)

   • Ask students: "What would happen if your device couldn't connect to any network?"
   • Have students list applications and services that would stop working
   • Discuss how dependent we've become on networked computing
   • Introduce the concept of computer networks

Main Activities (32 minutes)

3. Lecture: Network Fundamentals and Purposes (12 minutes)

   • Define a computer network as interconnected computing devices that can exchange data
   • Explain the main purposes of networks:
     • Resource sharing (files, printers, internet connection)
     • Communication (email, messaging, video calls)
     • Distributed processing (cloud computing)
     • Access to remote services and data
   • Introduce key network components:
     • Nodes (computers, servers, mobile devices, IoT devices)
     • Connection media (wired, wireless)
     • Network devices (routers, switches, access points)
   • Discuss different network types and scales:
     • Personal Area Networks (PAN)
     • Local Area Networks (LAN)
     • Wide Area Networks (WAN)
     • Metropolitan Area Networks (MAN)
   • Explain basic network models:
     • Client-server model
     • Peer-to-peer model
     • Hybrid approaches

4. Demonstration: Local Network Communication (8 minutes)

   • Show how devices on a local network communicate
   • Demonstrate basic network tools (ping, traceroute, ipconfig/ifconfig)
   • Explain IP addresses and how they identify devices on a network
   • Discuss the difference between local and global addressing
   • Show how data is broken into packets for transmission

5. Activity: Modeling a Simple Network with Paper Messages (12 minutes)

   • Divide class into groups of 4-6 students
   • Assign each student a role (client, server, router)
   • Give each student an "address" (number or name)
   • Provide index cards for writing messages
   • Have students simulate network communication by:
     • Writing messages on cards and addressing them
     • Passing messages through "routers" to reach destinations
     • Following simple routing rules
     • Handling message acknowledgments
   • Introduce challenges like message loss or node failure
   • Discuss how the network handled these challenges

Closing (10 minutes)

6. Discussion: Benefits of Networked Computing (5 minutes)

   • Lead a discussion on how networks enable modern computing
   • Ask students to identify benefits of networked systems
   • Discuss how networks have evolved over time
   • Address any misconceptions about networks

7. Exit Ticket: Network Concept Map (5 minutes)

   • Students create a concept map showing different types of networks and their characteristics
   • Concept map should include network types, components, and purposes
   • Students should show relationships between concepts
   • Collect concept maps before students leave

Assessment

• Formative: Participation in network simulation activity
• Exit Ticket: Completeness and accuracy of network concept map

Differentiation

For Advanced Students

• Ask them to include more detailed network protocols in their concept maps
• Have them research and explain more complex network topologies
• Challenge them to design a network solution for a specific scenario

For Struggling Students

• Provide a partially completed concept map template
• Focus on the most essential network concepts
• Use more visual aids and concrete examples

Homework/Extension

• Research and document the networks they use daily
• Compare home network setup with school or business networks
• Create a diagram of their home network with all connected devices

Teacher Notes

• Use analogies to help students understand network concepts (e.g., postal system for message delivery)
• Be prepared to address questions about specific network technologies
• Make connections to students' everyday experiences with networks
• Consider inviting a network administrator as a guest speaker
• Emphasize that understanding networks helps with troubleshooting connectivity issues