Alarm Analysis for LOP
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SONET/SDH Application
SQM (Sequence Indicator Mismatch): A SQM is declared when the
accepted sequence indicator (SQ) does not match the expected
sequence indicator (ExSQ). The SQM state is cleared when SQ
matches ExSQ.
Path: A Path alarm is declared when there is at least one near-end
path type alarm or a B3 error.
LOM (Loss Of Multiframe): A LOM is declared when the two
multiframe alignment processes is in the out-of-multiframe (OOM1
or OOM2) state and the whole Z7/K4 (bits 1 and 2) two-stage
multiframe is not recovered within 256 VT1.5/VT2 or VC-11/12
frames.
OOM1 (Out-Of-Multiframe of stage 1): A OOM1 is declared when
two consecutive Frame Alignment Signals (FAS) are detected in
error (i.e. one error in each FAS). The OOM1 state is cleared when
one non-errored FAS is found.
OOM2 (Out-Of-Multiframe of stage 2): An OOM2 is declared when
either the frame alignment process is in out-of-multiframe (OOM1)
state or when an error is encountered in the received and
expected frame count from bits 1-5 of the Z7/K4 bit 2 sequence.
The OOM2 state is cleared when the extended overhead
multiframe process is in the IM state and two consecutive
error-free frames are recovered.
SQM (Sequence Indicator Mismatch): A SQM is declared when the
accepted sequence indicator (SQ) does not match the expected
sequence indicator (ExSQ). The SQM state is cleared when SQ
matches ExSQ.
Path: A Path alarm is declared when there is at least one near-end
path type alarm, or a B3 error for TU-3 or BIP-2 for TU-11/TU-12.
Next-Generation Tabs
VCAT RX - Overview
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