Network Performance

Network Performance

1. bandwidth

   • speed is measured in bits per second
     • kilobits per second
       • megabits per second
         • gigabits per seocond
           • 1,000,000,000
         • 1,000,000
       • 1,000
     • This is the bandwidth
       • the bigger the bandwidth, the bigger the cost
       • if several users are on the network, there is less bandwidth individually as it is shared
         • the contention ratio is users : available bandwidth
           • you can buy a lower contention ratio connection to manage the amount of users accessing your network

2. wired networks

   • uses ethernet cables
     • cat5 (slower)
       • cheap and works for 100MB/s
     • cat6 (faster)
       • expensive but works for 1GP/s and more
     • plugged into switch
   • fibre-optic
     • transfer data using light that is reflected in the cable
       • has high bandwidth
       • expensive
   • not affected by radio interference

3. Bands

   • a range of frequencies (for radio technology)
     • Wi-Fi uses 2.4GHz and 5GHz frequency bands
       • both have different channels
         • reduces interference
         • amount of channels is regulated by law
       • 5.4GHz has a higher capacity and can carry many non-overlapping channels
         • shorter range and more expensive hardware
   • affected by other electronic devices that use radio technology on the same frequency
     • e.g. microwave

4. errors

   • happen when the signal is too weak or there is interference
     • binary numbers ( in instructions ) are flipped accidentally so a device receives a '1' instead of a '0'
   • latency ('delay')
     • larger networks-a bit takes longer to travel from one device to another