Internet Fundamentals: Protocols, Web Browsers, and Network Architecture

Internet vs. World Wide Web (WWW)

• Internet: A global network infrastructure that uses TCP/IP to connect devices worldwide.
• WWW (World Wide Web): A multimedia service built upon the Internet, utilizing HTML, CSS, web browsers, and hyperlinks.
• Webpage: A single document accessible via the WWW. | Website: A collection or group of related webpages.

History and Evolution of the Internet

• 1960s: Development of ARPANET (Advanced Research Projects Agency Network).
• 1983: Adoption of the TCP/IP protocol suite (developed by Vint Cerf and Bob Kahn).
• 1989: Invention of the World Wide Web (WWW) by Tim Berners-Lee.
• 1992: Release of the Mosaic browser (developed at UIUC), popularizing the graphical web.

Understanding the Client-Server Model

• Client: Initiates a request for content (e.g., a web browser).
• Server: Responds to the client's request by delivering the requested content or data.
• Two-tier Architecture: Simple direct connection (Client ↔ Server).
• Three-tier Architecture: Adds an intermediate layer, such as a database or application logic layer.

Network Transmission and Protocols

A Protocol defines the rules and standards for data exchange between devices.

• TCP/IP (Transmission Control Protocol/Internet Protocol): Responsible for splitting data into packets and routing them across the network.
• HTTP/HTTPS (Hypertext Transfer Protocol/Secure): Used for web browsing and secure data transfer.
• Email Protocols:
  • SMTP (Simple Mail Transfer Protocol): Sending email.
  • POP (Post Office Protocol) / IMAP (Internet Message Access Protocol): Receiving email.
• FTP/Telnet: Used for file transfer and remote terminal access, respectively.

IP Addresses, URLs, and DNS

• IP Address (Internet Protocol Address): A unique numerical identifier (e.g., 203.13.195.3), typically 32-bit (IPv4).
• URL (Uniform Resource Locator): A human-readable address used to locate resources (e.g., www.vu.edu.au).
• DNS (Domain Name System): Converts human-readable URLs into machine-readable IP addresses.
• TLDs (Top-Level Domains): Categories like .com, .edu, .org, .gov, .net, .mil, .au, .uk.

Standard Email Format

The standard format is username@domain (e.g., [email protected]).

Intranet vs. Extranet Comparison

Essential Internet Diagnostic Tools

• Tracert (Traceroute): Shows the path (hops) a data packet takes to reach its destination.
• Ping: Checks connectivity and measures the response time of a server.
• Nslookup: Used to query the DNS to resolve a URL to an IP address.
• Other Tools: Web browsers, antivirus software, FTP clients, and image manipulation tools.

Team Communication Tools: Slack Features

• Channels: Group chats that can be set as public or private.
• DMs (Direct Messages): Private, one-on-one communication.
• File Sharing: Easy sharing of documents, images, and links.
• Search Functionality: Ability to search across all messages and shared files.
• App Integration: Connects with external services like Google Drive, GitHub, and Twitter.

Web Browsers: Functionality and Structure

• Browser Definition: Software application used for accessing and viewing web content (HTML, PDF, multimedia, etc.).
• Primary Tasks: Viewing, navigating, downloading, emailing, and printing web content.

Key Components of a Browser Window

• Tabs: Allow users to open and manage multiple webpages simultaneously.
• Back/Forward Buttons: Used to navigate through the user's page history.
• Address Bar: Area where the user types or searches for a URL.
• Home Button: Returns the user to the designated startup or home page.
• Status Bar: Displays a link preview or status message when hovering over a hyperlink.

List of Popular Web Browsers

Major browsers include Google Chrome, Mozilla Firefox, Microsoft Edge, Apple Safari, Opera, and Tor Browser.

Google Chrome: Key Features

• Omni Box: A unified search and address bar where users can type URLs or search queries.
• Bookmarks: Saves favorite pages (indicated by the star icon).
• Extensions: Small programs that add customized features (e.g., AdBlock, Translate).
• Settings: Allows customization of themes, homepage, and startup pages.

Cache vs. Cookies: Data Storage Differences

• Cache: Stores copies of web resources (images, scripts) locally to significantly speed up future load times.
• Cookies: Small text files that store user preferences, login status, and session information.

Mnemonic: Cache = speed | Cookies = preferences

Customizing Browser Settings

• Users can set a specific homepage and install extensions or themes.
• Settings allow changes to privacy, security, and layout configurations.

Internet Search Mechanisms and Tools

Search Engine Components

Search engines (like Google, Bing, Yahoo) operate using three main components:

• Spider (Crawler): Collects and reads web pages.
• Indexer: Organizes and catalogs the collected data.
• Searcher (Query Processor): Retrieves relevant results based on the user's query.

Other Search Tools

• Directory: Websites manually categorized by human editors (e.g., botw.org).
• Metasearch Engine: Searches and aggregates results from multiple search engines simultaneously (e.g., Dogpile).
• Invisible Web (Deep Web): Content hidden from standard search engine indexing (e.g., proprietary databases, academic journals like IEEE Xplore).

Effective Search Techniques

• Use specific and targeted keywords.
• Try searching across multiple different engines.
• Use quotation marks (" ") for exact phrase matching.
• Utilize advanced search filters and operators.