Lesson Notes By Weeks and Term v5 - Grade 10

Lesson Video

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Performance objectives

• Define a computer network and its components.
• Differentiate between LAN, WAN, and MAN.
• Describe the advantages of using networks.
• Explain basic network topologies like bus, star, and ring.
• Identify basic network hardware like routers and switches.

Lesson summary

This week, we delve into the fascinating world of computer networks. Imagine trying to share a photo with a friend who lives far away without the internet – it would be a logistical nightmare! Computer networks, like the internet, provide the backbone for modern communication and data sharing. In South Africa, access to reliable and affordable networks is crucial for education, business, and connecting communities. From accessing online learning resources to processing payments at a local spaza shop, networks play a vital role in our daily lives.

Lesson notes

What is a Computer Network? A computer network is a collection of two or more computers that are connected together to share resources (such as files, printers, and internet access). These connections can be wired (using cables) or wireless (using radio waves). Think of it like a network of roads connecting different towns and cities. Each town is a computer, and the roads are the connections that allow data to travel between them.

Key Components of a Network: Computers/Devices (Nodes): The devices that are connected to the network, such as desktops, laptops, smartphones, and servers.

Network Interface Card (NIC): A hardware component that allows a computer to connect to a network. Each NIC has a unique MAC address. Think of it like the license plate of your computer on the network.

Transmission Media: The physical pathway that data travels on, such as cables (e.g., Ethernet cables, fibre optic cables) or radio waves (for Wi-Fi).

Network Operating System (NOS): Software that manages the network resources and allows users to access them. Examples include Windows Server and Linux.

Protocols: A set of rules that govern how data is transmitted over the network. The most common protocol is TCP/I

P. Think of it like the traffic rules that all cars must follow on the road. Hubs, Switches, and Routers: These are network devices that help manage and direct traffic on the network. We'll discuss them in more detail later.

Types of Networks: Local Area Network (LAN): A network that covers a small geographical area, such as a home, school, or office.

Example: The computers in your school's computer lab connected together.

Wide Area Network (WAN): A network that covers a large geographical area, such as a city, country, or the entire world. The internet is the largest WA

N. Example: A bank with branches across South Africa connected to a central server.

Metropolitan Area Network (MAN): A network that covers a metropolitan area, such as a city. MANs are larger than LANs but smaller than WANs.

Example: A network connecting different campuses of a university within Johannesburg.

Network Topologies: A network topology describes the physical or logical arrangement of devices on a network.

Bus Topology: All devices are connected to a single cable (the bus). This is a simple topology but is not very reliable. If the bus cable breaks, the entire network goes down. Imagine a single street with all houses connected to it; if the street is blocked, everyone is isolated.

Star Topology: All devices are connected to a central device (hub or switch). This is a more reliable topology than the bus topology. If one device fails, it doesn't affect the rest of the network. Most home and small business networks use a star topology. Think of it like a traffic circle; all roads connect to the circle, and if one road is blocked, the others can still function.

Ring Topology: Devices are connected in a circular fashion, with each device connected to two other devices. Data travels in one direction around the ring. This topology is not commonly used today.

Network Hardware: Router: A device that forwards data packets between networks. Routers connect your home network to the internet. They examine the destination IP address of each packet and send it along the best path.

Switch: A device that connects multiple devices within a network. Switches forward data packets only to the intended recipient, unlike hubs which broadcast data to all devices. This improves network efficiency.

Modem: A device that converts digital signals from your computer into analog signals that can be transmitted over telephone lines or cable TV lines (and vice versa). Modems are used to connect to the internet using older technologies like dial-up or DS

L. Modern modems are often built into routers.

Hub: A simple device that connects multiple devices together in a star topology. Hubs broadcast data to all connected devices, which can lead to network congestion. Hubs are rarely used in modern networks.

Advantages of Computer Networks: Resource Sharing: Networks allow users to share resources such as printers, files, and internet access. This saves money and increases efficiency. Think of sharing a printer between multiple computers in a school lab, rather than having a separate printer for each computer.

Communication: Networks enable easy and fast communication between users via email, instant messaging, and video conferencing. This improves collaboration and productivity.

Centralized Data Management: Networks allow for centralized storage and management of data, making it easier to back up and secure important information. Imagine a company storing all its financial data on a central server, making it easy to back up and protect against data loss.

Cost Savings: Sharing resources and centralizing data management can lead to significant cost savings for businesses and organizations.