A network in which clocks are controlled to run, ideally, at identical rates, or at the same mean rate with a fixed relative phase displacement, within a specified limited range. Note: Ideally, the clocks are synchronous, but they may be mesochronous in practice. By common usage, such mesochronous networks are frequently described as "synchronous. " 2. A network in which all clocks are normally (i.e., no-fault conditions) traceable to one or more primary reference sources, the difference in frequencies between them being negligible by definition.