This sets the fault threshold, in microseconds, for maximum Inter-Frame Delay Variation, following the same -1-disables, 0-or-greater-enforces convention explicitly described for its average-IFDV counterpart. An admin sets this specifically to catch a single severe frame-to-frame delay-variation spike, distinct from the average-IFDV threshold's concern with sustained behavior, and would set it to -1 on a service where even occasional IFDV spikes are considered acceptable. For example, cienaCesCfmDelayMsgMaximumDelayVariationThreshold set to 100 on a video-distribution circuit would raise a fault the instant any single measured IFDV spike exceeds 100 microseconds, even if the average IFDV stays comfortably low the rest of the time.