Chapter 2 – The Internet and World Wide Web

The Internet

  • Worldwide collection of interconnected networks linking millions of businesses, government agencies, educational institutions, and individuals.

    • Metaphor: Often described as the “network of networks.”

  • Originated as ARPANET in September\ 1969.

    • Initial goals:

    • Allow researchers to share information.

    • Function even if part of the network was destroyed (survivability via packet switching).

  • No single organization owns or controls the whole Internet; each organization maintains its own portion.

    • W3C (World Wide Web Consortium): develops research, sets guidelines and standards for Web technologies (HTML, CSS, XML, accessibility, etc.).

    • Internet2: high-speed private backbone (connecting 200+ universities & 115+ corporations) for next-generation Internet research.

Evolution of Home/Small-Business Access

  • Rapid shift toward broadband (high-speed) connections (cable, DSL, fiber, satellite, fixed wireless).

  • Access provider (ISP): business that offers Internet connectivity (free or fee-based).

    • Examples: cable operator, telephone company, cellular carrier, community wireless provider.

  • Data flow example

    1. User requests a Web page → digital signals leave computer.

    2. Cable modem converts digital data → RF signals → sends over coax into house drop.

    3. Signals share neighborhood coax segment (≈500 homes).

    4. Central cable system forwards traffic over high-speed fiber to cable operator/ISP.

    5. ISP routes across the Internet backbone → destination server.

    6. Server returns requested page → traverses the backbone → back through ISP → user PC.

IP Addresses & Domain Names

  • IP address: unique numeric identifier for every Internet-connected device.

  • Domain name: human-readable text mapping to an IP.

    • Examples: google.com, mit.edu.

  • Top-Level Domain (TLD) examples:

    • .com – Commercial organizations

    • .edu – Educational institutions

    • .gov – U.S. government

    • .mil – Military

    • .org – Non-profits

    • .biz, .info, .mobi, .travel, .pro, .coop, .museum, .name etc.

  • DNS server translates domain ↔ IP address pairs, facilitating the connection between users and web resources by allowing easier navigation through human-readable domain names.

  • World Wide Web (Web): global collection of electronic documents (Web pages) linked via hyperlinks.

  • Web site: group of related pages & assets stored on a Web server.

  • Web 2.0: sites enabling user interaction, collaboration, and content creation (blogs, wikis, social networks).

  • Home page: default/entry page a site or browser first displays.

  • URL (Uniform Resource Locator): unique Web address; syntax protocol://host/path (e.g., https://www.nps.gov/yell/index.htm).

  • Downloading: receiving data from the Internet; uploading: sending data to another computer.

  • Microbrowsers: stripped-down browsers for small screens (phones, smartwatches).

Web Browsers & Navigation

  • Browser: software to retrieve, render, and interact with Web pages (Examples: Chrome, Firefox, Edge, Safari, Opera, IE).

  • Browser launch & page fetch sequence

    1. User starts browser.

    2. Browser reads stored home-page URL.

    3. ISP DNS resolves domain → IP.

    4. Browser contacts Web server; server returns HTML; browser renders page.

  • Tabbed browsing: multiple pages in one window; switch via tabs.

  • Instant Search boxes let you query engines without visiting their homepage.

Search Tools

  • Two primary categories:

    1. Search engines (Google, Bing, Yahoo!, etc.): use crawlers + index to locate resources.

    2. Subject directories (Open Directory Project, Yahoo Directory): human-compiled, hierarchical catalogs.

  • Typical search workflow: enter query → engine returns ranked result set → click link → desired page loads.

  • Search operators to refine results:

    • Quotation marks for exact phrase ("information security").

    • Plus/Minus ( +include –exclude ).

    • site:, filetype:, intitle:, etc.

Categories of Web Sites (13 Types)

  1. Portal – gateways aggregating content/services (Yahoo!, MSN).

  2. News – current information (CNN.com).

  3. Informational – factual data (CDC.gov, Wikipedia).

  4. Business/Marketing – promote or sell products (Nike.com).

  5. Blog – personal/chronological commentary; vlog = video blog.

  6. Wiki – collaborative editing (Wikipedia).

  7. Online Social Network – build communities (Facebook, LinkedIn).

  8. Educational – learning resources (Khan Academy, Coursera).

  9. Entertainment – games, streaming media (Netflix, Twitch).

  10. Advocacy – promote causes (Greenpeace.org).

  11. Web Application – SaaS tools (Google Docs, Canva).

  12. Content Aggregator – collects & organizes (Feedly, Flipboard).

  13. Personal – individual or family pages.

Evaluating Web Content

  • No central authority reviews/polices Web info; users must judge:

    • Cross-verify statistics, look for citations, check update dates.

Multimedia on the Web

  • Multimedia = text + any combination of graphics, animation, audio, video, VR.

Graphics

  • Digital non-text visuals.

  • Major formats: BMP, GIF (supports animation & 256 colors), JPEG/JPG (lossy, photos), PNG (lossless, transparency), TIFF (high-quality, large).

  • Thumbnail: small preview linking to full-size file to save bandwidth.

  • Animation: illusion of motion via sequence of stills (GIF)

Audio

  • Music, speech, podcasts.

  • Usually compressed (MP3, AAC, OGG) to reduce size.

  • Played via media player (embedded or standalone).

  • Streaming audio: continuous playback while data downloads (e.g., Spotify, online radio).

  • Download workflow example:

    1. Search/purchase track → stored on Apple server.

    2. Download to PC.
      a. Listen on PC; b. Sync to portable player (iPod/iPhone) → listen via earbuds.

Video

  • Moving images are transmitted over the Internet using streaming technology, allowing users to watch content in real-time without needing to download the entire file first.

  • Streaming (YouTube, Vimeo) or progressive download.

Virtual Reality (VR)

  • 3-D simulation of real/imagined worlds; interact via input devices (mouse, keyboard, headset, gloves).

Plug-ins (Add-ons/Extensions)

  • Small programs expanding browser functionality (e.g., Adobe Reader, Flash Player, Java, Silverlight); modern browsers moving toward native support.

Web Publishing

  • Process of creating, uploading, and maintaining Web pages/site.

    1. Plan.

    2. Design.

    3. Create content

    4. Host on Web server.

    5. Maintain & update.

E-Commerce (Electronic Commerce)

  • Buying, selling, and exchanging goods/services via electronic networks.

    • B2C: Business → Consumer (Amazon, eBay).

    • C2C: Consumer → Consumer (Craigslist, Facebook Marketplace).

    • B2B: Business ↔ Business (Alibaba, supply-chain portals).

    • M-commerce: mobile device-based transactions.

  • E-retail transaction flow:

    1. Customer browses storefront page.

    2. Adds items to electronic cart.

    3. Enters payment data on secure page.

    4. Bank/processor authorizes funds.

    5. Web server confirms order.

    6. Fulfillment center packages & ships.

    7. Tracking posted online.

    8. Delivery; customer signs receipt.

Other Key Internet Services

  • E-mail: message/file delivery system that allows users to send and receive messages and documents over the Internet.

    • Flow: compose → outgoing mail server → routed via Internet → incoming server → recipient client.

  • Mailing list/Listserv: one address distributes to many; subscribe/unsubscribe mechanism.

  • Instant Messaging (IM): a real-time text communication service that allows users to chat and exchange files instantly, facilitating quick interactions over the Internet. (WhatsApp, FB Messenger, Slack).

  • Chat rooms: public group conversation spaces.

  • VoIP (Voice over IP): real-time voice (Skype, Zoom, FaceTime, SIP phones).

  • Newsgroups/Usenet: threaded discussions accessed through a newsreader. Message boards moved this online via Web interface.

  • FTP (File Transfer Protocol): standard for uploading/downloading files; secure variants

Netiquette (Internet Etiquette)

  • Core principles:

    • Use polite language; avoid ALL CAPS (interpreted as shouting).

    • Be concise and stay on topic.

    • Respect others’ privacy; do not forward personal emails without permission.

    • Cite sources, give credit.

    • Obey copyright and licensing.

    • Remember the human – tone can be misinterpreted.

    • Follow rules of specific forums/lists.