Networks

Networks

1. LAN and WAN

   • Local Area Network
     • Covers a small geographical area located on a single site
     • All the hardware used for a Lan is owned by the organisation that uses it
     • Often found in businesses, schools and universities
     • Advantages
       • Sharing files is easier
       • Collaborating on files is easier
       • Internet connection can be shared
       • Communication is easy
       • User accounts can be stored centrally
   • Wide Area Network
     • A WAN connects LANs that are in different geographical locations
     • An organisation will hire infrastructure, for example communication lines, from telecommunications companies
     • WAN is way more expensive than LAN
     • The internet is a wide area network
     • Can be connected using telephone lines, satellite links or radio links

2. Performance of networks

   • Bandwidth
     • The amount of data that can be transferred in a given time
     • Bandwidth shared between the users of a network
       • Too many users: Slow bandwidth
   • Choice of hardware
     • Wired connection
       • Generally faster than wireless
       • More reliable than wireless
     • Wireless
       • Slower than wired
       • Less reliable than wired
   • Interferences
     • Physical obstruction
     • Other devices

3. Hardware

   • Network Interface Controller
     • Allows a device to connect to a network.
     • Internal
     • Typically built into the motherboard
   • Switch
     • Switches connect devices on a LAN
     • Receives data as 'frames'
     • Media Access Control address (MAC)
       • Allows network interfaces to communicate
   • Router
     • Transmit data between networks in 'packets'
     • Always connected to at least two different networks
     • Connect LAN to the internet.