LANs & WANs

• When you connect one device to another, you're creating a network - networks aloow devices to share information and resources
• A LAN is a local area network
• A LAN covers a small geographical area located on a single site
• All the hardware for a LAN is owned by the organisation that uses it
• LANs are either wired (e.g. with Ethernet cables) or wireless (e.g. using wifi)
• You'll often find LANs in businesses, schools and universities
• Lots of homes have a LAN to connect various devices, such as PCs, tablets, smart TVs and printers
• A WAN in a network that connects LANs
• WAN stands for Wide Area Network
• A WAN connects LANs that are in different geographical locations. E.g. a business with offices in many different countries would need a WAN for all their devices to connect together
• Unlike a LAN, organisations hire infrastructure (e.g. communication lines) from telecommunications companies, who own and manage the WAN. This is because a WAN is much more expensive to set up than a LAN
• WANs may be connected using fibre or copper telephone lines, satellite links or radio links
• The internet is the biggest WAN
• Why use a LAN or WAN?

  • Sharing files is easier - network users can access the same files, work collaboratively on them (at the same time) and copy files between machines
  • You can share the same hardware (e.g. printers)
  • The internet connection can be shared between every device connected to the LAN or WAN
  • You can install and update software on all computers at once, rather than one by one
  • You can communicate with the users cheaply and easily
  • User accounts can be stored centrally, so users can log in from any device on the network
• Mbps stands for megabits per second, a measure of bandwidth
• Many factors can affect the performance of networks
• Bandwidth is the amount of data that can be transferred in a given time, e.g. 500 Mbps. The greater the bandwidth, the better the network can perform
• Available bandwidth is shared between the devices on a network - too many devices or heavy use (e.g. streaming video) may cause congestion and slow the network. You can limit the bandwidth available to individual users to address this
• Wired connections are generally faster and more reliable than wireless
• Fibre optic cables can give much better performance than copper cables
• Wireless performance depends on signal quality so is affected by the range of the device, the amount of interference from other wireless networks and physical obstructions like thick walls in buildings
• Choise of hardware other than cables and network topology also have a big effect on network performance