Lesson Notes By Weeks and Term v5 - Grade 10

Lesson Video

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Performance objectives

• Define key network components and their functions.
• Describe different network types (LAN, WAN, MAN) with SA examples.
• Explain bandwidth and latency.
• Identify network topologies and their pros and cons.
• Explain the concept of network protocols like TCP/IP.

Lesson summary

In today's interconnected world, understanding communication technologies and networks is no longer just for IT specialists. It's a crucial skill for everyone, especially in South Africa where access to information and communication can significantly impact opportunities for education, employment, and social participation. From using your phone to connect with family in another province to accessing online learning resources or even starting your own small business online, understanding these technologies empowers you to participate more fully in the modern world.

Lesson notes

2. 1. What is a Computer Network? A computer network is a group of two or more computer systems that are linked together to share resources, exchange files, or allow electronic communications. Think of it like a road network for data. Just as roads connect cities and towns, networks connect computers and devices.

Components of a Network: Client: A computer or device that requests services from a server. This could be your desktop computer at school accessing the internet or your smartphone accessing a social media app.

Server: A powerful computer that provides services to clients. This could be a web server hosting a website, a file server storing documents, or an email server handling email communication. Consider a school's server which stores all student data.

Transmission Medium: The physical pathway through which data travels between devices. This can be a wired connection (e.g., Ethernet cable, fibre optic cable) or a wireless connection (e.g., radio waves, microwaves).

Network Interface Card (NIC): A hardware component that allows a computer to connect to a network. Every computer or device that wants to connect to a network needs a NI

C. Think of it as the "adapter" that allows your computer to speak the network's language.

Router: A device that forwards data packets between different networks. Routers are crucial for connecting your local network to the internet. They act like traffic controllers, directing data to its correct destination.

Switch: A device that connects multiple devices within the same network. Unlike a router, a switch only forwards data to the intended recipient, improving network efficiency. 2.

2. Types of Networks Local Area Network (LAN): A network that connects devices in a limited geographical area, such as a home, school, or office. Typically, a LAN uses Ethernet cables or Wi-Fi to connect devices. For example, the computers in your school's computer lab are likely connected through a LA

N. Wide Area Network (WAN): A network that spans a large geographical area, such as a city, country, or even the entire world. The internet is the largest WAN. South African businesses with branches in multiple cities would use WANs to connect their offices.

Metropolitan Area Network (MAN): A network that connects devices in a city or metropolitan area. MANs are larger than LANs but smaller than WANs. A municipality might use a MAN to connect its various offices and departments.

Example: Imagine a small internet cafe in Khayelitsha (Cape Town). The computers inside the cafe are connected through a LAN. The cafe's internet connection, provided by a national ISP (Internet Service Provider), connects the LAN to the wider internet, which is a WAN. A MAN might be used to connect various public libraries within Cape Town. 2.

3. Bandwidth and Latency Bandwidth: The amount of data that can be transmitted over a network connection in a given period of time, usually measured in bits per second (bps), kilobits per second (kbps), megabits per second (Mbps), or gigabits per second (Gbps). Higher bandwidth means faster data transfer. Imagine bandwidth as the width of a pipe – the wider the pipe, the more water can flow through it at once.

Latency: The time it takes for a data packet to travel from one point to another on a network, usually measured in milliseconds (ms). Lower latency means faster response times. Think of latency as the delay it takes for a message to reach its destination. High latency can cause lag in online games or video conferencing.

Example: If you are streaming a movie online, high bandwidth is needed to download the video data quickly. Low latency is important to ensure that the video plays smoothly without interruptions. In South Africa, access to high bandwidth and low latency internet connections is often a challenge, particularly in rural areas. 2.

4. Network Topologies Network topology refers to the physical or logical arrangement of devices on a network.

Bus Topology: All devices are connected to a single cable (the bus). It is simple to set up but a break in the cable can bring down the entire network. Not commonly used today due to its vulnerability.

Star Topology: All devices are connected to a central hub or switch. This is the most common topology used in LANs. If one device fails, it doesn't affect the rest of the network.

Ring Topology: Devices are connected in a closed loop. Data travels in one direction around the ring. If one device fails, it can disrupt the entire network.

Analogy: Imagine a power grid. A bus topology is like a single power line serving multiple houses. If the line breaks, everyone loses power. A star topology is like each house having its own direct line to a central power station. If one house's line fails, the other houses are unaffected. 2.

5. Network Protocols Network protocols are a set of rules that govern how data is transmitted over a network.