The on-line gamers in your household will be very familiar with the term latency, but for the rest of us it's a slightly arcane figure. Basically it measures how quickly an external site responds to requests from your network, and is sometimes know as the "ping" time. The lower the latency, the more responsive your access to web sites and external services is likely to be.
Note that latency is not a measure of the bandwidth available on your connection (e.g. your latency may be great, but it could still take a very long time to download a large movie). The LuJam Advanced Cyber Protection Unit (ACPU) uses well-know websites, such as the BBC, to measure latency, as these are likely to give the most consistent and reliable latency figure for your network.
In addition to measuring responsiveness, latency is also a good way to detect problems with a network's connection to the Internet. The ACPU measures the number of failed responses. When this number rises, it's a sign that there is something amiss.
Usually, you'd be hoping for a latency of 5-10ms or less, but figures in the 20-60ms range are still quite usable for most office- and home-related activities. Over a period of time, the latency may vary quite considerably, sometimes going as high 100-300ms. For remote locations, the latency may be consistently high.
Note, the LuJam Security Protection Service detects loss of connection when it fails to receive a latency update from your network. This allows the service to raise an alert with you via SMS to warn of the loss of connection. An alert is raised only after a loss of connection of 2 minutes or more. Subsequent alerts are raised every 4 hours of continued lack of connectivity.