Both attempt to measure the speed of a network. If the data rate is the thing that is commonly measured in Mbps and latency is the thing that is measured in milliseconds, what are their similarities and differences?
I've tried searching google but the explanations I get are inconsistent. After searching "network latency" the first result is wikipedia but this definition pertains more to structural engineering than networks. The second result is about.com and it states
The term latency refers to any of several kinds of delays typically incurred in the processing of network data.
So does this mean latency is not a well-defined term and can mean whatever a person wants it to?
For example, when using
ping what does the latency actually measure (and out of curiosity why doesn't ping tell the data rate, in Mbps)?
What is the perceived difference between latency and data rate, is it that latency only matters until the download (or uploaded) first part has been received?