H31-341_V2.5 · Question #918
OTU_LOM is an alarm generated due to the out-of-multiframe (OOM) state lasting for 3ms.
The correct answer is A. True. Option A is correct because, per ITU-T G.709 standards, the OTU_LOM (Loss of Multiframe) alarm is declared precisely when the OOM (Out-of-Multiframe) defect condition persists for 3ms - this is the defined integration timer for escalating the OOM defect into the LOM alarm. The…
Question
OTU_LOM is an alarm generated due to the out-of-multiframe (OOM) state lasting for 3ms.
Options
- ATrue
- BFalse
How the community answered
(42 responses)- A71% (30)
- B29% (12)
Explanation
Option A is correct because, per ITU-T G.709 standards, the OTU_LOM (Loss of Multiframe) alarm is declared precisely when the OOM (Out-of-Multiframe) defect condition persists for 3ms - this is the defined integration timer for escalating the OOM defect into the LOM alarm. The relationship is hierarchical: OOM is the underlying defect state, and OTU_LOM is the alarm that gets raised only after that defect crosses the 3ms threshold.
Option B is wrong because the 3ms persistence requirement is explicitly defined in the ITU-T G.709 specification - this is not a variable or implementation-dependent value, making "False" factually incorrect.
Memory tip: Think of it as a two-stage trigger - OOM is the symptom, LOM is the alarm. The "3ms rule" is the timer that converts a transient hiccup (OOM) into a declared fault (LOM). Associate LOM → Lasts (3ms) to remember that duration is what separates the defect from the alarm.
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