Wi-Fi and Ethernet

Wi-Fi and Ethernet

1. Wi-Fi

   • How It Works
     • Electro-Magnetic Radiation
     • Waves move at lightspeed
     • Uses two states 'On' and 'Off'
   • Facts about Wi-Fi
     • Wi-Fi signals usually have a 20-30m radius
     • Wi-Fi signals move at lightspeed
     • Wavelength is usually around 12cm
     • Uses the 2.4GHz and 5GHz wavebands
       • 2.4GHz is the most common frequency but due to this there is a large amount of interferebce
       • 5GHz is a newer more expensive frequency but it is less common so there is less interference
       • 5GHz has a shorter range in which devices can pick up the signal
   • Problems that can occur
     • Other Wi-Fi signals can create interference
     • Physical objects can absorb or reflect Wi-Fi signals
     • Wireless networks are very easy to breach/hack into
   • Encryption
     • It is the transformation of a message so that it can only be seen by the intended viewer
     • Uses a data item known as a 'key'
     • A simple method of encryption is known as the Caesar cipher
       • Letters are displaced by a known amount such as 4
         • Each letter would then be represented by the value 4 letters after it eg. 'A' would become 'E'
   • Advantages
     • No restriction by cables
     • Wavebands can be split into channels to reduce interference
       • Adjacent channels can overlap which can cause interference or data corruption
       • Legal constraints restrict how many channels can be given to each waveband and how much power they can use
     • Cheaper than wired as it requires less hardware/cabling

2. Ethernet

   • The use of cables to make a wired connection between devices
   • More secure than a wireless connection as it requires a physical connection

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