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• Computer network


  Two or more computers connected to exchange data, can be computers or electronic devices
• Advantages of using computer networks

  • Easily share files and data
  • Share resources like printers and internet
  • Communicate via email, messaging, conferencing
  • Store data centrally on file server for easy access and backup
  • Keep settings centrally so can use any workstation
• Disadvantages of using computer networks

  • Greater risk of attacks and viruses
  • Significant cost of extra equipment
  • When network is down, computers cannot be used
• Hub


  Dumb device that sends data to all devices, causes network traffic, poor security, suitable for small home networks
• Switch


  Smart device that sends data to specific computers using MAC addresses, more secure and expensive, used in larger networks
• Router


  Connects computers to internet, routes packets from one network to another using routing table
• Modem


  Converts analog telephone signals to digital signals readable by computer, and vice versa
• Network interface card (NIC)


  Allows device to connect to network, contains MAC address to identify computer
• Bridge


  Connects two parts of a LAN network to function as a single LAN
• Wi-Fi


  Wireless networking technology to connect devices without cables, reduced cabling, easier to connect, but limited range, slower speeds, less secure
• Bluetooth


  Wireless networking for short range connections between devices like mouse, phone, printer, slower speeds, less secure, limited number of devices
• Ways to set up a network


  • ISP
  • Web browser
  • Email
  • Security
  • Router
  • Switch
  • Hub
  • Network cables
  • Firewall
  • Servers
• LAN (Local Area Network)


  Computer network within a building, easy to manage and share files, but easier to spread viruses and dependent on main server
• WLAN (Wireless LAN)


  Same as LAN but wireless, uses access points instead of switches
• WAN (Wide Area Network)


  Network that joins multiple LANs over a large area, considered the internet
• Internet

  Public global network of networks, more information and less security than private intranets
• Devices to access the internet

  • Laptop computers
  • Desktop computers
  • Tablets
  • Smartphones
• Laptop computers


  More portable and smaller than desktops, bigger screens than tablets, but touchpads may be difficult and processors not as fast
• Desktop computers


  Have stable wired internet connection, use mouse for easier navigation, but must be connected to power supply
• Tablets and smartphones


  Highly portable and easy to carry, can access internet via phone networks, but have smaller screens, touchscreens may be difficult, and limited battery life
• The internet should be policed to prevent illegal materials and incorrect information being published
• The internet should not be policed as it would be expensive, difficult to enforce globally, and go against freedom of information
• Advantages of information on websites

  • More likely to be up to date than books
  • Easier to get information
  • Vast amount of information available
• Disadvantages of information on websites

  • Information could be correct or incorrect/inaccurate
  • Risk of information overload making it difficult to find exact information
• Website security


  Passwords, anti-spyware software, regularly changing strong passwords
• Authentication


  Techniques like user IDs, passwords, digital certificates, biometrics, magnetic strips to verify data source
• Antivirus software


  Runs in background, compares files to known virus database, quarantines suspected infected files
• Ways to avoid viruses on the internet


  • Avoid unknown/suspicious websites
  • Avoid opening emails/attachments from unknown sources
  • Use common sense
• Fax (physical)


  Dedicated fax machine connected to phone line, user places document, dials number and presses send, document printed at receiving end
• Fax (electronic)


  Fax service with specific fax number, sender emails attachment to number, receiver gets notification and can print
• Advantages of electronic fax

  • Cheaper, encrypted transmission, can send to email or print
  • Disadvantages of physical fax: hard copy to hard copy
• Video conferencing


  Uses both sound and video, requires webcams, monitors, microphones, speakers, potential issues with jerky images and time lags
• Audio conferencing


  Uses audio only, organizer dials participants and sets up meeting, can be done via internet telephony (VoIP)
• Web conferencing (webinar)


  Requires computer and internet, participants join and leave, mute and unmute, used for presentations and education
• Computer Network


  Two or more computers or other devices connected together so that can exchange data
• Advantages of using Network

  • Easily share files / data / printer / internet/communicate with other users/store data on one file server/setting is centrally
• Disadvantages of using Network

  • Risk of hacker / virus / if server is down can't use computers/ printer developing / equipment is costly
• Network devices


  • Hubs
  • Switches
  • Modem
  • Bridges
  • Router
  • NIC
  • Network cables
  • Gateway
• Hubs


  • To connect computers/devices to make LAN / poor secure / suitable for home network
• Switches


  • To connect number of computers / devices to make LAN / more secure / used in office/ school/ large network