3com MSR 20-20 참조 매뉴얼

alarm-threshold { ais { level-1 | level-2 } | lfa { level-1 | level-2 | level-3 | level-4 } | 
los { pulse-detection | pulse-recovery } value }

CT1/PRI interface view

ais: Sets the alarm threshold of alarm indication signal (AIS), which can be level-1 
and level-2.

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The level-1 keyword specifies to generate an AIS alarm when the number of 0s 
in the bit stream of an SF or ESF frame is less than or equal to 2.

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The level-2 keyword specifies to generate an AIS alarm when the number of 0s 
is less than or equal to 3 in the bit stream of an SF frame or less than or equal 
to 5 in the bit stream of an ESP frame.

By default, level-1 AIS alarm threshold applies.

lfa: Sets the loss of frame align (LFA) alarm threshold, which can be level-1, 
level-2, level-3, and level-4.

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The level-1 keyword specifies to generate an LFA alarm when two of four 
frame alignment bits are lost.

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The level-2 keyword specifies to generate an LFA alarm when two of five 
frame alignment bits are lost.

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The level-3 keyword specifies to generate an LFA alarm when two of six frame 
alignment bits are lost.

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The level-4 keyword applies only to ESF frames. It specifies to generate an LFA 
alarm when errors are detected in four consecutive ESF frames.

By default, level-1 LFA alarm threshold applies.

los: Sets a loss of signal (LOS) alarm threshold, which can be pulse-detection (for 
the pulse detection duration threshold with LOS) and pulse-recovery (for the 
pulse threshold with LOS).

The threshold of pulse-detection, in units of pulse intervals, ranges from 16 to 
4,096 and defaults to 176.

The threshold of pulse-recovery, ranges from 1 to 256 and defaults to 22.