Computer Studies (AKU-CS)
Topic 4 of 7Aga Khan Board

Networking & Internet

Network types, protocols, the internet and cybersecurity

Networks connect devices to share resources and communicate.


Types:

  • LAN (Local Area Network): covers small area (school, office). Owned by the organisation.
  • WAN (Wide Area Network): covers large geographic area. Internet is the world's largest WAN.
  • Wireless networks: use radio waves (Wi-Fi). **Wired:** use cables (fibre optic = fastest, immune to interference; copper/ethernet).

    • Network topologies:

  • Star topology: all devices connect to a central switch/hub. If one device fails, others work. If hub fails, all fail.
  • Bus topology: all devices on one cable. Easy to set up, cheap, but slow and if cable breaks all fail.

    • Protocols are agreed rules for communication:

  • HTTP/HTTPS: web browsing (S = secure, encrypted)
  • FTP: file transfer
  • SMTP/POP3/IMAP: email sending/receiving
  • TCP/IP: core internet protocol — breaks data into packets, routes them, reassembles

    • IP address: unique address for each device on a network (e.g., 192.168.1.1).

    DNS: converts domain names (seekhoasaan.com) into IP addresses.


    Cybersecurity threats: phishing (fake emails), malware (viruses, ransomware), hacking.

    Protection: strong passwords, antivirus software, firewalls, HTTPS, two-factor authentication (2FA).

    Key Points to Remember

    • 1LAN: small area; WAN: large area; Internet = global WAN
    • 2Star topology: central hub; bus topology: shared cable
    • 3TCP/IP: routes data packets; DNS: name to IP address
    • 4Cybersecurity: phishing, malware; protect with firewall + 2FA

    Pakistan Example

    Pakistan's Internet Shutdown Incidents — Networking in Real Life

    Pakistan has experienced multiple internet shutdowns (2022-2024) where ISPs (Internet Service Providers) were ordered to block certain IPs and domains. This directly involves DNS blocking and IP filtering — AKU-CS topics. Jazz, Telenor, and Zong all use WAN infrastructure. Karachi's KHI-IX internet exchange point is Pakistan's main internet hub.

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