Lesson Notes By Weeks and Term v5 - Grade 12

Lesson Video

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Performance objectives

• Describe and differentiate between network topologies and types.
• Explain the function of key networking devices.
• Describe client-server and peer-to-peer network models.

Lesson summary

This week, we delve into the crucial topic of networks, the internet, and emerging technologies. Understanding these concepts is no longer optional; they are fundamental to participation in the modern South African economy and global society. From accessing online learning resources to participating in digital entrepreneurship, from using mobile banking to communicating with family, networks and the internet underpin almost every aspect of our lives. Emerging technologies are reshaping industries, creating new job opportunities, and demanding a digitally literate workforce.

Lesson notes

2.1 Network Topologies and Types Network Topology: Refers to the physical or logical arrangement of nodes and connections in a network.

Bus Topology: All devices are connected to a single cable (the bus). Simple but prone to collisions and a single point of failure.

Example:* Imagine a small spaza shop using a shared ethernet cable to connect their point-of-sale system and back-office computer. If the cable breaks, the entire network is down.

Star Topology: All devices connect to a central hub or switch. More reliable than bus, as a single device failure doesn't affect the whole network.

Example:* A school computer lab where each computer connects to a central switch. If one computer fails, the others can still access the network.

Ring Topology: Devices are connected in a circular fashion, with data passing from one device to the next. Less common now due to difficulty in troubleshooting.

Example:* Old token ring networks used in some banking systems (less prevalent now).

Mesh Topology: Every device is connected to every other device. Highly redundant and reliable but expensive and complex to implement.

Example:* The core of the internet uses a mesh topology for high availability.

Network Types: Defined by their geographical scope and purpose.

LAN (Local Area Network): Connects devices within a limited area, such as a home, office, or school.

Example:* A Wi-Fi network in your house or a wired network in your school's IT lab.

WAN (Wide Area Network): Connects devices across a large geographical area, such as a city, country, or the world. The Internet is the largest WA

N. Example:* A network connecting different branches of a bank across South Africa.

MAN (Metropolitan Area Network): Connects devices within a city or metropolitan area. Larger than a LAN but smaller than a WA

N. Example:* A network connecting all municipal buildings in Johannesburg.

PAN (Personal Area Network): Connects devices within a person's immediate vicinity, typically using Bluetooth or Wi-Fi.

Example:* Connecting your phone to your wireless earbuds or using Bluetooth to connect your phone to your car's infotainment system. 2.2 Networking Devices Router: Forwards data packets between networks. It determines the best path for data to travel from source to destination, using routing protocols. Routers connect your home or office network to the internet.

Example:* Your home Wi-Fi router connects your devices to your ISP's network.

Switch: Connects devices within a single network (LAN). It learns the MAC addresses of connected devices and forwards data only to the intended recipient, improving network efficiency.

Example:* In a school computer lab, a switch connects all the computers to the same network.

Hub: A simpler and less intelligent version of a switch. It broadcasts data to all connected devices, leading to more collisions and lower performance. Hubs are rarely used in modern networks.

Modem: Modulates and demodulates signals, allowing devices to communicate over telephone lines or cable connections.

Example:* A DSL modem converts digital signals from your computer into analog signals that can be transmitted over telephone lines, and vice versa. 2.3 Client-Server and Peer-to-Peer Networks Client-Server: A network model where a central server provides resources and services to client devices.

Advantages:* Centralized management, enhanced security, better performance for resource-intensive tasks.

Disadvantages:* Server failure can disrupt the entire network, requires dedicated hardware and administration.

Example:* A school network where students access files and applications from a central server.

Peer-to-Peer (P2P): A network model where devices share resources directly with each other, without a central server.

Advantages:* Easy to set up, cost-effective for small networks, no single point of failure.

Disadvantages:* Decentralized management, security risks, slower performance, difficult to scale.

Example:* Sharing files directly between two computers in your house using a network cable. 2.4 Ethical and Societal Implications of Emerging Technologies Artificial Intelligence (AI): The development of computer systems that can perform tasks that typically require human intelligence, such as learning, problem-solving, and decision-making.

Ethical Concerns:* Job displacement due to automation, bias in algorithms, privacy concerns related to data collection and use.

Societal Impact:* Increased efficiency in various industries, improved healthcare diagnostics, personalized learning experiences.

South African Context:* AI can be used to improve access to education and healthcare in underserved communities, but careful consideration must be given to its ethical implications.

Internet of Things (IoT): The network of physical devices, vehicles, appliances, and other objects embedded with sensors, software, and network connectivity that enables them to collect and exchange data.