Lesson Notes By Weeks and Term v4 - SHS 3

Lesson Video

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Performance objectives

• Identify key network devices: hubs, routers, and switches.
• Demonstrate how to configure a network device.
• Explain the steps to connect a network to the internet.
• Understand basic network security measures.

Lesson summary

In our daily lives in Ghana, we are constantly connected. We use WhatsApp to chat with family, watch videos on YouTube, check WASSCE results online, and even use mobile money services. All these activities depend on our devices—phones, laptops, and computers in internet cafes—being connected to the Internet. This lesson demystifies that process. We will explore the "magic" behind the connection, looking at the key hardware and the steps required to set up a small network and link it to the global internet. Understanding this is a fundamental skill for any 21st-century citizen and a critical area of knowledge for computing students.

Lesson notes

This topic involves understanding the devices that make up a network and the rules (protocols) they follow to communicate. A. Core Network Devices

To build a network, we need specific hardware. The three most common devices you will encounter are hubs, switches, and routers. The Hub (The "Dumb" Repeater) Function: A hub is the simplest and least intelligent of the network devices. Its job is to take any data packet it receives on one port and broadcast it out to *all* other ports. Analogy: Imagine you are in a crowded room and you want to talk to one person. Instead of speaking to them directly, you shout your message so that everyone in the room hears it. Only the intended person acts on it, but everyone else is disturbed. Key Feature: It operates in a single collision domain. This means if two devices try to send data at the same time, the data packets "collide," become corrupted, and have to be re-sent. This makes hubs very inefficient, especially as more devices are added. Modern Relevance: Hubs are largely obsolete and have been replaced by switches. The Switch (The "Intelligent" Mail Sorter) Function: A switch is smarter than a hub. When a device sends a data packet, the switch reads the destination MAC Address (a unique hardware address for every network card) contained in the packet. It then creates a direct connection and sends the packet *only* to the intended recipient's port. Analogy: Think of an office mailroom. Instead of shouting everyone's mail, the clerk reads the name on each letter and places it directly in the correct person's mailbox. It's efficient and private. Key Feature: Each port on a switch is its own collision domain. This drastically reduces data collisions and makes the network much faster and more efficient than one using a hub. Switches are used to create Local Area Networks (LANs). The Router (The "Gateway" to the World) Function: A router's primary job is to connect different networks together. Most importantly, it connects your local network (LAN) to the a Wide Area Network (WAN), such as the Internet. It directs traffic between these networks. Analogy: A router is like the main post office in Accra. The local mail sorter (the switch) handles mail within the Cantonments area (the LAN). But when you want to send a letter to Kumasi or London (another network/the Internet), you send it to the main post office (the router), which knows the best route to get it there. Key Feature: Routers use IP Addresses (Logical Addresses) to determine the best path for data to travel between networks. Most modern home routers also include a built-in switch and a wireless access point.

Summary Table:

| Device | Function | How it Works | Analogy | | :--- | :--- | :--- | :--- | | Hub | Connects devices in a LAN (inefficiently) | Broadcasts data to all ports | Shouting in a room | | Switch | Connects devices in a LAN (efficiently) | Sends data only to the destination MAC address | Office mail sorter | | Router| Connects different networks (e.g., LAN to Internet) | Uses IP addresses to find the best path | Main post office | B. The Process of Connecting to the Internet

Evaluation guide

• Demonstrate how the system can connect to the Internet.
• Demonstrate the configuration of network devices (e.g., hub, router, switch) to establish
• connectivity within a network.
• Explain the steps involved in connecting a network system to the internet, including