Communication, Internet & Networks – Comprehensive Study Notes

Module Objectives – Week 5: Communication & the Internet

  • By the end of Week 5 you should be able to:
    • Discuss the evolution of the Internet and the Web
    • Describe practical Web use (pages, sites, browsers, URLs)
    • Identify techniques and hardware for connecting to the Internet (hotspots, tethering, wired/wireless options)
    • Explain common online activities, services, and Web apps
    • Apply safety considerations for secure online behaviour
    • Utilise social networks appropriately and safely
    • Conduct and refine online searches; evaluate information quality
    • Recognise ethical/legal issues when using online content

Internet Evolution

  • Web = service of inter-linked websites delivered over the Internet (originally “World Wide Web”)
  • Internet = global collection of millions of interconnected networks
  • Origin: 1960s ARPANET (U.S. DoD – ARPA)
    • Goals: (1) share scientific information from geographically separated sites; (2) remain operational if nodes destroyed (e.g.
      nuclear attack)
    • Initial 4 hosts: UCLA, UCSB, Stanford Research Institute, Univ. of Utah
  • Bandwidth = channel capacity (data rate)
  • Net neutrality = all websites/services treated equally by ISPs
  • ISP (Internet Service Provider) must deliver equal service regardless of content/purpose
  • Early infrastructure illustrated by 1974 ARPANET map (Fig 2-2)

Using the World Wide Web

  • Web page = formatted document containing text, graphics, audio, video, hyperlinks
    • Static page: same content on every visit
    • Dynamic page: generated anew on each visit (e.g. stock quotes, weather)
  • Hyperlink = clickable word/graphic pointing to another resource
  • Website = collection of related web pages + associated files located on a Web server
    • Web server can host many sites
  • Responsive Web Design adapts layout to screen size
  • Core technologies:
    • HTML – structure & layout (headings, paragraphs etc.)
    • CSS – design, appearance
  • Popular browsers (Table 2-1): Apple Safari, Google Chrome, Microsoft Edge, Mozilla Firefox – each offers unique features (independent tabs, OneDrive integration, plugins, parental controls, etc.)
  • Cookies = small text files generated by server to store user data (items viewed, login status)
  • Breadcrumbs = navigation path recorded by browser; Back/Forward buttons rely on it
  • Address bar shows URL (Uniform Resource Locator) of current page; Fig 2-6 identifies URL parts (protocol, domain, path, etc.)
  • IP address = unique numeric identifier; IPv4 (0\text{–}255 per octet, e.g. 69.32.132.255) & IPv6 (128-bit hexadecimal)
  • DNS translates domain names to IP addresses; DNS servers usually managed by ISPs

Connecting to the Internet

  • Hot spot = wireless device/location providing Internet access
    • Mobile hot spot uses cellular data to share with other devices (Fig 2-8)
  • Cellular networks: 4G (broad coverage), 5G (higher speed, higher bandwidth)
  • Public Wi-Fi available in cafés, hotels, etc.; smartphone hotspot capabilities may incur provider fees & consume data quota
  • Tethering = sharing phone’s connection via USB, Bluetooth or Wi-Fi; “USB tethering” option answers Knowledge Check 2-2

Online Activities & Services

  • Information/Research (libraries, encyclopaedias), Educational, Business, Government, Blogs (time-stamped posts)
  • Health/Fitness, Science, Entertainment portals (music, video, games)
  • Bookmarking sites: organise & tag links; tags aid retrieval/comments
  • Social media = broad term for Internet-based sharing & interaction
  • Online banking/trading: worldwide access to financial records
  • Web apps – Pros: device-agnostic, easy collaboration, no update installs, storage savings; Cons: need always-online, provider outages, security/privacy risks, fewer features (Table 2-32)

Online Safety Considerations

  • Secure website uses encryption (https – HyperText Transfer Protocol Secure)
  • Encryption scrambles data until decrypted
  • Digital certificates verify identity using trusted third-party signatures (Fig 2-22)
  • Safety tips:
    • Verify site safety (check https, certificate)
    • Disable location sharing when unnecessary
    • Clear browsing history & refuse password storage
    • Use phishing filters, pop-up blockers, private browsing, proxy servers

Communicating Online

  • Email – original Internet service enabling global messaging (Fig 2-24)
  • Messaging services/apps provide real-time text, multimedia, voice, voice-to-text & group discussions (e.g. Facebook Messenger)
    • Notify when contacts are online; can join private chat rooms
  • Typical email path outlined in Fig 2-25

Using Social Networks

  • Major network categories & examples (Tables Fig 40-41):
    • Social networking: Facebook, LinkedIn
    • Blogging/Microblogging: Twitter, WordPress
    • Media sharing: YouTube, Flickr
    • Collaborative projects: Wikipedia, message boards
    • Social curation/bookmarking: Reddit, Delicious
    • File sharing: Dropbox, WeTransfer
  • Privacy/Security risks:
    • Register cautiously, manage profiles, choose/limit friends, share minimal info, scrutinise urgent requests

Information Literacy & Web Searches

  • Search engines deploy spiders/crawlers to index web pages
  • Query = search term submitted for results
  • Web directory = human-curated subject guide (alphabetical)
  • Basic search strategy steps depicted in Fig 2-35
  • Boolean/Search operators (Table 2-45):
    • “phrase” – exact match
    • | or OR – either term
    • - (hyphen) – NOT
    • * – wildcard
    • #..# – numeric range
  • Knowledge Check 2-3: correct term is “Query”

Responsible & Ethical Use of Online Content

  • Anyone can publish anything; apply CARS (Credible, Accurate, Reasonable, Supportable) checklist
  • Citation = formal reference to source; plagiarism & copyright infringement risks
  • Intellectual property rights protect creators; violating (e.g. copying photos) is illegal
  • DRM technologies (authentication, encryption, watermarks) protect digital works
  • Public domain = no copyright; Creative Commons licences allow sharing with conditions
  • Ethics: moral principles governing behaviour; must cite non-common-knowledge info; tools like Word generate bibliographies (Fig 2-37)

Case Studies & Knowledge Check Answers – Week 5

  • Knowledge Check 2-1: ISP definition = Internet Service Provider (answer c)
  • Case Study 2-1: Web server needs Domain Name + IP Address (answer c)
  • Discussion prompts: benefits of Internet for organisations, cyberspace fraud mitigation, etc.

Module Objectives – Module 9: Networks & Network Devices

  • Explain user interaction with networks
  • Identify network structures (topologies, architectures, reach)
  • Describe network standards and protocols
  • Use hardware to connect to a network
  • Set up home/business networks
  • Employ security tools to protect networks
  • Understand network professional roles & ethics

Network Fundamentals & Interaction

  • Network = two or more devices linked via wired, wireless or telecom channels
  • Allows sharing of hardware, software, data, Internet access
  • Digital communications: sending/receiving devices + communication devices (modem, router) + transmission media (wired/wireless)
  • Table 9-1 lists component roles (sending device, comms device, channel, receiving device)
  • Home vs Business networks:
    • Home: single building, few users, easy install
    • Business: many users, multiple buildings, high data volumes
  • Capabilities (Fig 9-6): shared Internet, files, hardware, gaming; business adds central backup & employee communication
  • Intranet = internal private network; Extranet = controlled external access; VPN = encrypted remote access over Internet
  • Wired vs Wireless:
    • Wired faster & more secure; Wireless easier to deploy
    • Cellular networks (3G/4G/5G) use radio links
  • Communications software establishes connections, manages data flow, provides user interface

Network Structures

  • Classification by topology, architecture & geographic reach
  • Common topologies (Table 9-2):
    • Bus – single central cable; failure stops entire network
    • Mesh – devices interconnected; partial/full versions; alternate routes increase resilience
    • Ring – sequential data path; obsolete
    • Star – devices connect to central switch; central failure cripples network, device failure isolated
    • Tree = multiple stars linked via bus
  • Architectures:
    • Client/Server – dedicated servers provide resources, managed by administrator (Fig 9-5)
    • Peer-to-Peer (P2P) – <10 computers share resources equally; Internet P2P file sharing may violate copyright
  • Geographic reach:
    • LAN, WLAN, MAN, WAN, PAN, BAN (wearable biosensors)

Network Standards & Protocols

  • Standards = guidelines for media, access, speeds (e.g. Ethernet)
  • Protocol = rules for data format, error handling, sequence
  • TCP/IP family:
    • TCP – routing & reliability; IP – unique addressing (IPv4 32\text{ bits}, IPv6 128\text{ bits})
  • Close-distance protocols (Table 9-4): Wi-Fi (802.11 a/b/g/n/ac/ax up to 7\text{ Gbps}), Bluetooth (≤3\text{ Mbps}, ≤9 m), UWB, IrDA (infra-red line-of-sight), RFID (tags & readers), NFC (contactless payments), LTE (cellular)
  • Wi-Fi integrates with Ethernet; may need extenders
  • Knowledge Check 9-1: IrDA is only protocol listed that does NOT use radio waves

Network Connection Hardware

  • Nodes = any connected devices
  • Hub vs Switch vs Router:
    • Hub broadcasts to all ports; Switch sends to intended device; Router connects multiple networks/routes traffic
  • Modems: cable, DSL, ISDN (digital/broadband); connect LAN to ISP
  • Dedicated digital lines (Table 9-5): Cable, DSL/ADSL, ISDN, FTTP (fiber), ATM, T-Carrier (T1, T3) – multiplexed, high-speed, expensive

Setting Up a Network (Home Example)

Step-by-step (Table 100):

  1. Purchase modem/router, connect to ISP service
  2. Enable Wi-Fi, set SSID & strong key (WPA2/WPA3)
  3. Enable device Wi-Fi, select SSID, enter key
  • Adding wireless printer: place within range, connect to SSID, install manufacturer app (Fig 9-12)
  • Boosting range: extend antennas, add signal booster/repeater, centralise router (Fig 9-13)
  • Case Study 9-1: Marina’s slow room connection due to weak signal; solution = improve signal strength (answer c)

Securing a Network

  • Risks: adware, spyware, viruses, worms, trojans, ransomware, rootkits (Table 9-6)
  • Mitigations:
    • Change default router admin password & SSID
    • Enable WPA2/WPA3 encryption, MAC filtering
    • Limit connected devices; monitor via admin interface
    • Firewalls (hardware/software) & stealth mode
    • Authentication (username/password, biometrics)
    • Encryption for data in transit; NAS for centralised secure storage
    • Network monitoring software & packet sniffers (both defensive & malicious uses)

Network Professional Responsibilities

  • Network administrator: plan, design, procure, install, secure, maintain networks; role of trust (Fig 9-15)
  • USENIX: professional body supporting sysadmins
  • Ethical code topics: professionalism, social responsibility, integrity, privacy, law, communication, system integrity, education, responsibility to computing community

Case Studies & Knowledge Check Answers – Module 9

  • Knowledge Check 9-1 answer: IrDA
  • Case Study 9-1 answer: Improve wireless signal strength
  • Discussion prompt: Bluetooth – advantages (low power, cable-free), disadvantages (range, security)

Self-Assessment Prompts (Weeks 5 & 9)

  • Reflect on known vs new concepts, social media usage, cybercrime experiences, browser preferences, topics needing further study, confusing sections