networks and effects of using them

• Networked


  When two or more computers are joined so that they can share information with each other
• ISP

  Internet Service Provider
• Router

  Allowing only authorised machine to connect to other computer systems
• Modem


  Allows one computer to connect to another and transfer information through telephone lines
• Browser

  A program that allows the user to find and view pages on the world wide web.
• Email

  Can be used to send and receive messages over the Internet
• URL

  Uniform resource locator
• WLAN

  Wireless Local Area Networksending radio signals over relatively short distance
• Bluetooth


  wireless communication between specific devices
• Use of Bluetooth

  freedom of movementprinterssynchronize contact details
• Disadvantage of network

  reduced securityextra hardware needed for it to operate
• LAN

  Local Area Networkconsists of number of computers and peripheral devices joined together over a small area
• Bus network

  All data are sent along the cable and terminators are used to absorb signals so they don't reflect back and cause data corruption

  
• Star network

  Each device in the network has its on cable that connects to a hub or switch

  
• WAN

  Wide Area NetworkSpread over a large geographical area than a LAN
• Video Conferencing


  communicating long distance using voice and video
• Fax


  scans paper a line at a time and sends this over the telephone network
• Communication medium


  is what allows the signals to be transmitted around the network work.
• Twisted pair cables

  reduce interference with the signals
• Fibre optic cables


  Which cables are used to transfer information for the Internet over long distances at high speeds?

  
• NIC

  Network Interface Card allows the communication medium to send and receive messages
• hub


  messages received by all

  
• switch


  messages to specific device
• bridge


  the device which allows two dissimilar networks to send messages from one to another
• Advantages of routers

  1. make decisions whether message should be passed between networks2. change the format of the message3. decide best route4.join two unlike networks
• Proxy server

  computer on a network which acts on behalf of another, or through which all internet data must pass
• Firewall


  A system designed to prevent unauthorised access to your computer when connected to a network such as the Internet
• Intranet


  a network designed for the exclusive use of computer users within an organization that cannot be accessed by users outside the organization
• Internet


  A global network connecting millions of computers, making it possible to exchange information.
• Confidentiality of data


  efforts to guarantee the privacy of personal health info
• Encryption

  Process of converting readable data into unreadable characters to prevent unauthorized access.
• Authentication techniques

  Techniques used to verify a genuine person on the network or communications system.