Network Types and Topologies

• What is a computer network?


  Two or more computers connected together to share information and resources. This can involve wired or wireless connections, or a combination of both
• What is a PAN?


  A Personal Area Network is a network that covers a very short range of only a few metres. It is often formed when connecting personal devices together, such as a smartphone and wireless headphones. It uses Bluetooth to connect devices, and is used by only one person.
• What is a LAN?

  A Local Area Network is a connection of computers and devices which covers a small geographical area of one site, such as a home, school or office. Each device is known as a node. The infrastructure of a LAN is usually owned by the organisation. It uses wired and wireless connections.
• What is a WAN?

  A Wide Area Network covers a large geographical area, involving multiple sites, which can span across a region or even internationally. The infrastructure can be provided by a third party, such as telecoms companies like BT, and the ownership is often shared between organisations because it is expensive to own and maintain. It can use satellites, leased lines, wired and wireless connections.
• What are the advantages of networks?

  • Digital communication between people
  • Sharing of digital information
  • Sharing of peripheral devices such as scanners and printers
  • Computers can be updated and backed up centrally
  • A single program can be run simultaneously on multiple computers
• What are the disadvantages of networks?

  • They require expertise to install and maintain, which can be expensive
  • There are security issues with unauthorised access to data
  • If a hacker gains access to one computer, it can use the network to gain access to the other computers
• Describe copper cables


  They are made up of a twisted pair of copper wires, and transmit data using electrical signals. This means that they are subject to interference, and have a range of up to 100 metres. They are the cheaper option.
• Describe fibre optic cables


  Made up of glass fibres, and transmit using light signals. This means that they are very fast, not subject to interference and have a range of over 2 kilometres. They are the more expensive option.