This value specifies, in seconds (0 to 600), the delay threshold above which a tmnxDot1agCfmMepDMTestComplete notification is sent for a one-way-delay test; a value of zero sends a notification on completion of any test regardless of measured delay. An admin sets a nonzero threshold matched to the service's latency SLA, so an alert only fires when the measured one-way delay actually exceeds what the service is supposed to guarantee. A notification firing here on a link that shouldn't have significant latency is worth investigating for a routing or queuing problem introducing unexpected delay.