ABSTRACT
Resolution is the degree to which one hardware clock reading can be distinguished from another, normally equal to the reciprocal of the clock oscillator frequency. Precision is the degree to which an application can distinguish one clock reading from another, defined as the latency to read the system clock, and is a property of the hardware and operating system. The clock filter algorithm greatly reduces network jitter and removes most spikes for each server separately, but spikes can also occur when switching from one server to another. Popcorn spike suppressors are used in the clock filter and discipline algorithms to avoid these spikes. They operate by tracking the exponentially averaged jitter and discarding a spike that exceeds a threshold equal to some multiple of the average. In practice, clock steps in the Internet are very rare and almost always indicate a hardware, software, or operational failure.
