Whenever you use the internet digital packets of data are being sent to and received from the website or service that you are using. Generally this happens incredibly quickly, just a few milliseconds to complete a round trip so you are unlikely to pay much attention to how long it takes, however, the Round Trip Time or Latency can be more significant on certain types of internet connections. A poor ADSL connection, for example, may be over 100ms but a satellite connection will always be over 600ms. This may not sound that significant but it is when you consider how many packets of data are going backwards and forwards. The effect of this latency is particularly significant for voice conversations and encrypted traffic such as VPNs.