WDD Module II: Access and Analyze Online Information PDF

 1.1. Introduction to the Internet The Internet and the World Wide Web (WWW) are two closely intertwined technologies that have revolutionized the way we communicate, access information, and conduct business in the modern world. Defining the internet The Internet is the global...

 1.1. Introduction to the Internet The Internet and the World Wide Web (WWW) are two closely intertwined technologies that have revolutionized the way we communicate, access information, and conduct business in the modern world. Defining the internet The Internet is the global network of interconnected computers and devices, allowing them to communicate and exchange data with each other. It's a vast, decentralized network that spans the globe, connecting billions of devices, including personal computers, servers, smartphones, and more. This network operates on a set of standardized protocols and technologies. The Internet's primary function is to facilitate data transfer between devices, making it possible for us to send emails, share files, browse websites, and stream videos. It doesn't host content itself; rather, it serves as the infrastructure that enables the transfer of information..  History of the Internet  the internet was born out of a need to share information and connect people around the world.  On October 29, 1969, an organization called ARPANET (Advanced Research Projects Agency) launched the first iteration of the internet (also known as ARPANET) connecting four major computers at The University of Utah, UCSB, UCLA, and Stanford Research Institute.  When this network of computers was connected, universities were able to access files and transmit information from one organization to the other, as well as internally.  As researchers developed the system, they continued to connect computers from other universities, including MIT, Harvard, and Carnegie Mellon. Eventually, ARPANET was renamed “internet.” Who used the internet in this stage? In its earliest days, the internet was only used by computer experts, scientists, engineers, and librarians who had to learn a complicated system in order to use it, but as the technology improved and consumers adapted, it became an essential tool for people around the globe. How and when did the functionality of the internet change? The 1970s was a serious time of transition for the internet. Email was introduced in 1972, libraries across the country were linked, and above all, information exchange became more seamless thanks to Transport Control Protocol and Internet Protocol (TCP/IP) architecture. The invention of these protocols helped to standardize how information was sent and received over the web, making the delivery more consistent, regardless of where or how you’re accessing the internet. When did the internet become user-friendly? Then in 1986, the National Science Foundation took the development of the internet to the next echelon by funding NSFNET, a network of supercomputers throughout the country. These supercomputers laid the groundwork for personal computing, bridging the gap between computers being used exclusively for academic purposes and computers used to perform daily tasks. In 1991, The University of Minnesota developed the first user-friendly internet interface, making it easier to access campus files and information. The University of Nevada at Reno continued to develop this usable interface, introducing searchable functions and indexing. When did consumers begin using the internet? As the internet’s development continued to evolve and shift focus, the National Science Foundation discontinued its sponsorship of the internet’s backbone (NSFNET) in May of 1995. This change lifted all commercial use limitations on the internet and ultimately, allowed the internet to diversify and grow rapidly. Shortly after, AOL, CompuServe, and Prodigy joined Delphi to offer commercial internet service to consumers. The debut of WiFi and Windows 98 in the late nineties marked the tech industry’s commitment to developing the commercial element of the internet. This next step gave companies like Microsoft access to a new audience, consumers (like yourself). WHAT DOES INTERNET USAGE LOOK LIKE TODAY? Flash-forward to today. It’s estimated that three billion people now use the internet, many of whom use it on a daily basis to help them get from Point A to Point B, catch up with loved ones, collaborate at work, or to learn more about important questions like how does the internet work? As technology changes and the internet weaves its way into just about every aspect of our lives, even more people are expected to use it. In 2030, researchers project there will be 7.5 billion internet users and 500 billion devices connected to the internet. How the Internet Works The Internet is based on a layered architecture consisting of multiple protocols and technologies. Understanding the functioning of the Internet is crucial for anyone delving into web design and development. The Internet, a globally interconnected network of devices, facilitates the exchange of information on an unprecedented scale. To comprehend how it works, we must explore its fundamental components and the intricate processes that underpin this vast digital ecosystem. The modern Internet is a vast network of networks, consisting of millions of private, public, academic, business, and government networks of local to global scope. 1. Devices and Endpoints: At the heart of the Internet are the myriad devices that form its nodes—computers, smartphones , servers, routers, and more. Each device is assigned a unique identifier known as an IP (Internet Protocol) address. This addressing system allows seamless communication between these devices across the network. Client computers connect to the internet through an ISP. Example: Your phone connected to a mobile network or your laptop connected to WiFi. 2. Physical Network Infrastructure The foundation of the Internet is its vast array of physical components. This includes: Cables: These include copper telephone wires, TV cables, and fiber optic cables. Undersea cables also play a crucial role in intercontinental data transmission. Routers and Switches: These devices manage traffic within and between networks by forwarding data packets to their intended IP addresses. Servers: Central to data exchange, servers store, send, and receive data. Web servers, for instance, host websites and send their data to other devices. Data Centers: These facilities house large numbers of servers and other computing hardware. They are essential for cloud computing services and extensive data storage and processing. 3. Internet Service Providers (ISPs): Internet Service Providers (ISPs) are essential organizations that facilitate access to the internet for individuals, businesses, and organizations. They serve as gateways to the broader internet infrastructure, providing various types of internet connections including broadband (cable, DSL, fiber optics), wireless, satellite, and even traditional dial-up services. ISPs manage the transmission of data across the internet, ensuring that everything from emails to streaming content is moved efficiently between users and the wider web. Additionally, many ISPs offer services like domain registration and web hosting, allowing users to purchase domain names and host websites on ISP servers.  SPs also play a critical role in network security by implementing measures to protect their networks and customers from cyber threats such as malware, hacking, and unauthorized access. This includes monitoring network traffic for suspicious activities and providing firewall options. Furthermore, they are responsible for maintaining and upgrading the physical network infrastructure necessary for internet connectivity, including cables, routers, and switches. Some prominent examples of ISPs include Comcast (Xfinity) and AT&T in the USA, which offer a wide range of services including internet, TV, and telephone services; BT Group in the UK, known for its fiber-optic services and digital TV packages; Deutsche Telekom in Germany, providing extensive telecommunications services across Europe; Airtel in India, which offers mobile and broadband services; offering a broad range of telecommunications services both domestically and internationally. Also in our country Ethio telecom and Safaricom are Internet service providers that are responsible to provide the service throughout the county. Through their diverse offerings and pivotal role in data management, ISPs are foundational to the operation and accessibility of the global internet. 4. Protocols and Standards Internet protocols are the set of rules and standards that define how data is transmitted and communicated across networks. These protocols ensure that devices on the internet can communicate with each other effectively, despite differences in hardware, operating systems, and internal configurations. Let’s take a brief look at some of the key protocols that keep the Internet TCP/IP (Transmission Control Protocol/Internet Protocol): The backbone of Internet communication is the TCP/IP protocol suite. This suite manages the transmission of data by breaking it into packets, assigning addresses, and ensuring the reliable delivery of information between devices. o TCP is one of the main protocols of the Internet Protocol Suite. It ensures the reliable transmission of data between a source and destination. TCP breaks down data into smaller packets, manages the transfer of these packets across the network, and reassembles the packets at the destination. It provides error-checking and guarantees that data will arrive in order and without errors. For example, when you download a file, TCP ensures that all parts of the file reach your device correctly IP is responsible for addressing and routing packets so that they can travel across networks and arrive at the correct destination. Devices on the Internet have unique IP addresses that identify them and enable communication. IP operates at a lower level than TCP and does not guarantee the delivery of packets; it relies on TCP for error handling and reassembly. DNS (Domain Name System):  Translates human-readable domain names into machine-readable IP addresses.  The DNS acts as a virtual phone book, translating human-readable domain names into IP addresses.  This essential service enables users to access websites using easily memorable names, simplifying the user experience and abstracting the complexity of numerical IP addresses. HTTP/HTTPS (Hypertext Transfer Protocol/Secure):  Protocols for transmitting web data. HTTP is the protocol used by the Web to transfer data over the Internet.  It allows for the fetching of resources, such as HTML documents.  It's a request/response protocol between clients and servers.  A browser, for instance, may request a webpage using HTTP, and the server will respond with the content of that page.  HTTPS adds a layer of encryption to secure the data. Simple Mail Transfer Protocol (SMTP):  SMTP is the standard protocol for email transmission across networks.  It is used when email is sent from a client to a server or between servers.  SMTP only covers the sending of emails; other protocols like IMAP and POP3 are used for retrieving and storing messages. File Transfer Protocol (FTP):  FTP is used for the transfer of files from one host to another over the Internet.  It supports two modes of data transfer: ASCII and binary.  FTP is useful for moving large files and is commonly used by websites to upload or download multimedia files.  These protocols are fundamental to how the Internet operates, allowing for a wide range of online activities and services.  Understanding these protocols helps students grasp the technical foundations of Internet communication and how data flows across the network. 5. Clients:  Clients (End-users) interact with the Internet through web browsers, such as Chrome or Firefox.  These applications send requests to servers, interpret responses, and render web pages, handling diverse content types like HTML, CSS, and JavaScript to create the interactive web experience. 6. Web Servers: Web servers store and deliver web pages in response to client requests. Equipped with software like Apache or Nginx, they process incoming requests, retrieve the requested files, and send them to the user's browser, forming the backbone of the client-server architecture. 7. Data Transmission: Data travels across the Internet in the form of packets. These packets navigate a network of routers and switches, dynamically choosing the most efficient path based on routing algorithms to ensure optimal and timely delivery. 8. Firewalls and Security Measures: Firewalls act as gatekeepers, protecting networks from unauthorized access and potential cyber threats. Additional security measures, such as encryption through SSL/TLS and Virtual Private Networks (VPNs), contribute to securing data during transmission. 10. IP addresses  Every computer on the internet is assigned a series of numbers, like 172.217.9.206.  That series of numbers uniquely identifies the computer over the internet.  If a URL like (www.google.com) is a nickname for a website, an IP Address (like 8.8.8.8) is its real name.IPv4 (Internet Protocol Version 4) and IPv6 (Internet Protocol Version 6) are versions of the Internet Protocol, which is used to identify devices on a network and route traffic across the internet. IPv4  IPv4 uses a 32-bit address scheme, allowing for a theoretical maximum of approximately 4.3 billion unique addresses.  Due to the exponential growth of the internet and the number of devices connected to it, IPv4 addresses are now nearly depleted.  An IPv4 address is typically displayed in decimal digits, separated by dots. Example of an IPv4 Address: 92.168.1.1 IPv6  While IPv4 has limitations due to a finite address space, IPv6 was introduced to accommodate the ever-growing number of connected devices and ensure the sustainability of the Internet.  To address the depletion of IPv4 addresses and It uses a 128-bit address scheme. This allows for a vastly larger number of devices to be connected directly to the internet. IPv6 addresses are written in hexadecimal and separated by colons. Example of an IPv6 Address: 2001:0db8:85a3:0000:0000:8a2e:0370:7334  IPv6 not only provides more address space but also includes enhancements for security and routing efficiency compared to IPv4.  Transitioning to IPv6 has been gradual, with both protocols coexisting in the current internet infrastructure to ensure compatibility and seamless connectivity.  In Conclusion , the Internet operates as a seamlessly interconnected network, orchestrating the flow of data through standardized protocols, addressing schemes, and secure communication mechanisms.  This intricate web of technologies and processes sustains the global exchange of information, shaping the digital landscape we navigate daily. 1.1.4. Applications of the Internet  The Internet's significance extends far beyond its technical infrastructure; it has become an integral part of contemporary society.  The Internet has democratized information access, empowering individuals with a wealth of knowledge.  Socially, it has facilitated global connections and transformed the way people interact.  Economically, it has given rise to ecommerce and new business models.  The Internet's influence on society is profound, shaping how we communicate, work, and navigate the modern world Using the internet: ✓ A college student uses a smart phone to record a stunning touchdown, and then uploads the video to allow others to view it. ✓ While walking down the street in a city, a teenager runs an app to find others nearby who are interested in playing an online game. ✓ A person suffering from a chronic disease wears a battery- powered monitor that sends an update to their doctor every fifteen minutes. ✓ A family on vacation uses a smart phone to contact their home security system and see views of the interior of their home. ✓ Software developers who live in different areas of the world can collaborate on a project by working on the codes simultaneously.  Here's a brief overview of some key applications of the Internet that have had significant impacts on modern society: 1. Communication: One of the primary uses of the Internet is communication. Email services like Gmail and Outlook allow people to send messages instantly across the globe. Social media platforms such as Facebook, Twitter, and Instagram have transformed how we socialize, enabling us to share and connect with others in real-time. Video conferencing tools like Zoom and Skype support both personal and professional interactions, facilitating virtual meetings, classes, and family gatherings. 2. Information and Research: The Internet is a vast repository of information, accessible via search engines like Google, Bing, and Yahoo. Whether it's historical facts, scientific data, or the latest news, the Internet provides an unparalleled wealth of resources for research and learning. Online encyclopedias, scholarly articles, and tutorials offer invaluable support for educational and professional development. 3. Entertainment: The Internet provides a wide range of entertainment options. Streaming services like Netflix, Hulu, and YouTube offer movies, TV shows, and user-generated content available at the click of a button. Online gaming platforms connect players from around the world, and music streaming services like Spotify and Apple Music give users access to millions of songs and podcasts 4. E-Commerce: Online shopping has become a staple, with websites like Amazon, eBay, and Alibaba offering the ability to purchase almost anything from the comfort of home. This extends to food delivery from restaurants, grocery shopping, and the global marketplace of goods and services, all facilitated by the Internet. 5. Education: The Internet has dramatically expanded access to education. Online courses, virtual classrooms, and e-learning platforms like Coursera, Udemy, and Khan Academy make it possible for anyone with an internet connection to learn new skills or earn degrees. Educational resources are more accessible than ever, catering to different learning styles and needs. 6. Healthcare: Telemedicine is an emerging field where the Internet plays a crucial role. Patients can consult with doctors online, receive remote diagnoses, and manage prescriptions without needing to visit a clinic in person. Online health resources, patient portals, and mobile apps for health management further exemplify the Internet's impact on healthcare. 7. Banking and Finance: Internet banking allows consumers to manage their finances online, from transferring funds to trading stocks. Financial services have become more accessible, and the Internet also supports the emergence of digital currencies and mobile payment systems like PayPal and Venmo. 8. Cloud Computing: The delivery of computing resources, including storage, servers, and software, over the Internet, providing on-demand access and scalability.  1.2. Introduction to the World Wide Web (WWW) The World Wide Web, commonly referred to as the Web, is one of the most influential innovations that operates on the Internet. It has revolutionized the way we access and share information, connect with others, and engage in various online activities. The World Wide Web is a system of interlinked hypertext documents accessed via the Internet. It provides a graphical interface for navigating and accessing information, allowing users to browse websites and interact with web-based applications. With a web browser, users can view web pages that may contain text, images, videos, and other multimedia and navigate between them via hyperlinks. The Web utilizes the Internet to transmit its data, making it a vast information- sharing model built on top of the existing infrastructure.  1.2.2. The Internet VS The World Wide Web The terms Internet and World Wide Web are used interchangeably in nonprofessional terms they are not the same. It is common practice to say "going on the Internet" whenever we open any web page on a browser. however, the World Wide Web or the Web is one of the most popular Internet services available. The Web is a collection of interconnected documents (web pages) and other web resources, linked by hyperlinks and URLs. It uses HTTP as an underlying protocol for information transfer, which is one of the several other protocols available in networking theory.  The Internet is a massive network of networks, a networking infrastructure that connects millions of computers globally, allowing them to communicate. The World Wide Web is a way of accessing information over the medium of the Internet. It is an information-sharing model that is built on top of the Internet.  1.2.3. History of the World Wide Web the WWW was invented by Sir Tim Berners-Lee in the late 1980s while working at CERN, the European Organization for Nuclear Research. His goal was to create a system that would allow researchers to easily share and access information across different computer platforms. The World Wide Web has undergone a significant evolution since its inception. Initially, it consisted mainly of static web pages with basic text and images. Over time, advancements in web technologies led to dynamic content, interactive features, and multimedia integration. The emergence of Web 2.0 introduced user-generated content, social media, and collaborative platforms. Further developments, including the rise of mobile internet and the semantic web, continue to shape the WWW's evolution, making it a dynamic and ever-expanding platform for information dissemination and online interaction.  1.2.4. How the World Wide Web Works Now, we have understood that WWW is a collection of websites connected to the internet so that people can search and share information. Now, let us understand how it works! The Web works as per the internet's basic client-server format as shown in the following image. The servers store and transfer web pages or information to user's computers on the network when requested by the users. A web server is a software program which serves the web pages requested by web users using a browser. The computer of a user who requests documents from a server is known as a client. Browser, which is installed on the user' computer, allows users to view the retrieved documents.  All the websites are stored in web servers. Just as someone lives on rent in a house, a website occupies a space in a server and remains stored in it. The server hosts the website whenever a user requests its Webpages, and the website owner has to pay the hosting price for the same. The moment you open the browser and type a URL in the address bar or search something on Google, the WWW starts working. There are three main technologies involved in transferring information (web pages) from servers to clients (computers of users). These technologies include Hypertext Markup Language (HTML), Hypertext Transfer Protocol (HTTP) and Web browsers. The World Wide Web is a complex system that enables the easy retrieval and sharing of information over the internet. To understand how the Web works, it is crucial to look at its structure, components, and the step-by-step process of accessing web content. Here’s a breakdown to illustrate this:  1.2.4.1 Structure and Components Web Pages: Web pages are documents, typically written in HTML (Hyper Text Markup Language), that can contain text, images, videos, and other multimedia. They are the building blocks of websites. Web Browsers: Web browsers, such as Google Chrome, Mozilla Firefox, and Safari, are software applications used to access web pages. They interpret HTML files and display them as web pages. Web Servers: Web servers are computers set up to respond to requests for web pages. They store, process, and deliver web pages to users. Hyperlinks: Hyperlinks, or links, connect web pages to one another. They allow users to navigate between related pages and websites easily. URLs (Uniform Resource Locators): URLs are web addresses that point to a specific web page. Each URL is unique and directs the browser to a particular resource on the web. HTTP/HTTPS (HyperText Transfer Protocol/Secure): These protocols govern how data is transmitted between web browsers and servers. HTTPS adds a layer of encryption for security  1.2.4.2 Step-by-Step Process of Accessing the Web 1. Entering a URL: The process begins when a user enters a URL into a web browser. For example, entering https://www.example.com. 2. DNS Lookup: The browser performs a DNS (Domain Name System) lookup to translate the URL into an IP address that points to a specific web server. For instance, www.example.com might translate to 192.0.2.1. 3. Browser Sends HTTP Request: The browser sends an HTTP request to the web server at the resolved IP address, asking for the web page associated with the URL. 4. Server Processes Request: The web server receives the request, processes it, and sends back the requested web page, often along with associated resources like images and CSS files. 5. Browser Displays Web Page: The browser receives the data and renders the web page for the user to view. This includes formatting based on HTML and CSS, and executing any JavaScript to make the page interactive. 6. Navigation Using Hyperlinks: While viewing the web page, the user can click on hyperlinks to access other related pages. Each click results in new HTTP requests to the server, repeating the process. Understanding these components and steps provides insight into the fundamental workings of the World Wide Web, explaining how it allows for easy, efficient access to a vast amount of information across the globe.  1.2.4.3 HTTP and HTTPs HTTP (Hypertext Transfer Protocol): HTTP is an client-server protocol that allows clients to request web pages from web servers. It is an application level protocol widely used on the Internet. Clients are usually web browsers. When a user wants to access a web page, a browser sends an HTTP Request message to the web server. The server responds with the requested web page. By default, web servers use the TCP port 80. Clients and web servers use request-response method to communicate with each other, with clients sending the HTTP Requests and servers responding with the HTTP Responses. Clients usually send their requests using GET or POST methods, for example GET /homepage.html. Web servers responds with a status message (200 if the request was successful) and sends the requested resource. An example will clarify this process:  The client wants to access http://Example.com and points his browser to the URL http://example.com (this is an example of an HTTP Request message). The web server hosting http://example.com receives the request and responds with the content of the web page (the HTTP response message). However, HTTP operates over an unencrypted channel, which means the data exchanged between the user's browser and the server is susceptible to interception and manipulation by malicious entities. this lack of encryption poses a security risk, especially when transmitting sensitive information such as login credentials or personal details. While HTTP is suitable for static websites and information that doesn't involve sensitive data, its vulnerability to interception makes it less ideal for secure transactions or interactions that demand data integrity and confidentiality. To address these security concerns, a more secure variant, HTTPS, was developed. In Browsers, you can immediately recognize that a web site is using HTTP. it appears like the following image.  HTTPS (Hypertext Transfer Protocol Secure): HTTPS, or Hypertext Transfer Protocol Secure, is an extension of HTTP designed to provide a secure and encrypted connection between the user's browser and the web server. The security is implemented through the use of SSL (Secure Sockets Layer) or its successor, TLS (Transport Layer Security), protocols. The encryption ensures that the data exchanged between the user and the server remains confidential, preventing eavesdropping and tampering. One of the key features of HTTPS is the use of SSL/TLS certificates. Websites that implement HTTPS have these certificates, which are verified by trusted third-party entities called Certificate Authorities. When a user accesses an HTTPS-enabled website, their browser checks the authenticity of the SSL/TLS certificate. If valid, the browser establishes a secure connection, and the web address usually displays "https://" along with a padlock icon, indicating a secure connection.  HTTPS is essential for any website that handles sensitive information, such as online transactions, login credentials, or personal data. It provides users with confidence in the security of their interactions with the website, fostering trust and protecting against various cyber threats, including man-in-the-middle attacks. In Internet Browsers, you can immediately recognize that a web site is using HTTPS because a lock appears to the right of the address bar:  HTTP Vs HTTPS In summary, while HTTP is suitable for basic web browsing and information retrieval, HTTPS adds a layer of security crucial for safeguarding sensitive data on the internet. The adoption of HTTPS has become increasingly important, not only for e-commerce and banking websites but also for any platform that values user privacy and data security. As the internet evolves, HTTPS continues to be the recommended standard for secure communication, ensuring the integrity and confidentiality of data exchanged between users and websites.