Lesson Notes By Weeks and Term v5 - Grade 10
Internet technologies and web concepts – Week 5 focus
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Internet technologies and web concepts – Week 5 focus
Download the Lessonotes Mobile South Africa app for faster lesson access on Android and iPhone.
Subject: Information Technology
Class: Grade 10
Term: 3rd Term
Week: 5
Theme: General lesson support
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This week, we delve deeper into the fascinating world of Internet Technologies and Web Concepts. Understanding how the internet works is crucial in today's digital age. From accessing educational resources online to participating in e-commerce, the internet has become an integral part of our lives, especially here in South Africa where access is growing rapidly and transforming communities. Learning these concepts empowers you to be more than just users; you'll understand the underlying mechanisms that shape your online experiences and open doors to exciting career opportunities in IT. We will particularly focus on the client-server model, IP addresses, domain names, and URLs this week.
2.1 The Client-Server Model: The client-server model is the foundation of internet communication. It's a distributed application structure that divides tasks between servers (resource providers) and clients (resource requesters). Think of it like ordering food at a restaurant. You (the client) place your order with the waiter (the network), who delivers it to the kitchen (the server). The kitchen prepares the food (processes the request) and sends it back to you via the waiter.
Client: A client is any device or application that requests services from a server. Examples include web browsers (Chrome, Firefox, Safari), email programs (Outlook, Gmail), and mobile apps. Clients initiate communication.
Server: A server is a computer or a software program that provides services to clients. These services can include hosting websites, storing data, sending emails, or running applications. Servers are typically powerful computers with high bandwidth and storage capacity, always "listening" for client requests.
Why it matters: This model allows for centralized resource management, increased security, and scalability. If every device had to host every piece of information, the internet would be incredibly slow and inefficient.
Example: When you type `www.gov.za` into your browser (the client), your browser sends a request to a server hosting the Department of Government's website (the server). The server then sends the website's files (HTML, CSS, JavaScript, images) back to your browser, which displays the website on your screen. 2.2 IP Addresses (Internet Protocol Addresses): Every device connected to the internet has a unique IP address, similar to a physical address for your house. It's a numerical label assigned to each device participating in a computer network that uses the Internet Protocol for communication. IP addresses allow devices to locate and communicate with each other.
IPv4 (Internet Protocol version 4): The original IP address format, consisting of four sets of numbers (octets) separated by dots, e.g., `192.168.1.1`. Each octet can range from 0 to
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5. IPv4 addresses are 32-bit, meaning they can represent approximately 4.3 billion unique addresses. This is now insufficient to address all devices connected to the internet.
Problem: IPv4 address exhaustion! The increasing number of internet-connected devices has led to a shortage of IPv4 addresses.
IPv6 (Internet Protocol version 6): The newer IP address format, designed to address the IPv4 shortage. It consists of eight groups of four hexadecimal digits, separated by colons, e.g., `2001:0db8:85a3:0000:0000:8a2e:0370:7334`. IPv6 addresses are 128-bit, providing a significantly larger address space (3.4 x 10^38 addresses!).
Why it matters: Without IP addresses, devices wouldn't know where to send data. IPv6 is essential for the future growth of the internet as more devices connect.
Example: Think about sending a letter via the South African Post Office. You need the street address, suburb, city, and postal code for the letter to reach its destination. The IP address acts as the digital version of this physical address for data packets on the internet. Many ISPs (Internet Service Providers) in South Africa are transitioning to IPv6. 2.3 Domain Names: Domain names are human-readable addresses for websites, making it easier to remember and access them. Instead of typing a complex IP address like `172.217.160.142`, you can type `www.google.com`.
Domain Name System (DNS): A hierarchical and decentralized naming system for computers, services, or any resource connected to the Internet or a private network. The DNS translates domain names into IP addresses, allowing your browser to connect to the correct server. When you type a domain name into your browser, your computer sends a request to a DNS server, which looks up the corresponding IP address. The DNS server then returns the IP address to your computer, allowing your browser to establish a connection with the web server.
Why it matters: Domain names make the internet user-friendly. Imagine trying to remember a long string of numbers for every website you visit! DNS is the invisible "phone book" of the internet.
Example: When you type `www.uct.ac.za` into your browser, the DNS system translates this domain name into the IP address of the University of Cape Town's web server. 2.4 URLs (Uniform Resource Locators): A URL is the address of a resource on the internet. It specifies the protocol used to access the resource, the domain name (or IP address) of the server hosting the resource, and the path to the specific file or page on the server.
Structure of a URL: ``` protocol://domain_name/path/to/resource ``` Protocol: Specifies the method used to access the resource (e.g., `http`, `https`, `ftp`). `https` is the secure version of `http` and encrypts communication between your browser and the server.
Domain Name: The human-readable address of the server (e.g., `www.example.com`).