4.2

• Router


  • Connects together two or more networks
  • Can connect a home or business network (LAN) to the Internet (WAN)
  • Can incorporate a firewall to provide network security
  • Stores information about the computer(s) connected to each of the networks
  • Inspects every packet of data being sent by any computer on the networks connected to it using a routing table
• What routers do


  1. Read data and decide where to send it

  2. Decide on the fastest route in which to send the data

  3. Make the format of the data suitable for the network where it is being sent
• Routing table


  Contains information like computer addresses (IP address)
• Network cables


  • Plugged into a computer's wired network interface card and connects it to the network
  • Used to send data around the network
• Network cables


  • Can transfer data faster than wireless
  • Data transferred over cables is more secure than over wireless (Hackers can't intercept data easily)
• Network cable wires


  • Some wires are used to send data to the computer
  • Some wires are used to receive data from the computer
• Hub


  • A device that connects a number of computers together to make a LAN
  • Receives a message, sends it to every computer on the network
• Hubs are 'non-intelligent' devices and they don't manage any of the data that flows through them
• Switch


  • Stores the MAC Addresses of all devices on the network
  • Uses the look up table to match the MAC address of an incoming data packet at one of its ports, and directs it to the correct device
• Modem


  • Modulates signals to encode digital information and demodulates signals to decode the transmitted information
  • Turns the digital data of a computer into modulated electrical signal for transmission over telephone lines and demodulated by another modem at the receiver side to recover the digital data