Friday, 22 March 2013

Maintenance signals in SDH & abbreviations

Let us read about maintenance signals in SDH.


LOS     Drop of incomming optical power level causes BER of 10-3   or worse
OOF     A1, A2 incorrect for more than 625 us
LOF      If OOF persists of 3ms
B1 Error    Mismatch of the recovered and computed BIP-8
MS-AIS      K2 (bits 6,7,8) =111 for 3 or more frames
B2 Error   Mismatch of the recovered and computed BIP-24
MS-RDI     If MS-AIS or excessive errors are detected, K2(bits 6,7,8)=110
MS-REI     M1: Binary coded count of incorrect interleavedbit blocks
AU-AIS      All "1" in the entire AU including AU pointer
AU-LOP    8 to 10 NDF enable or 8 to 10 invalid pointers
HP-UNEQ  C2="0" for 5 or more frames
HP-TIM     J1: Trace identifier mismatch
HP-SLM    C2: Signal label mismatch
HP-LOM    H4 values (2 to 10 times) unequal to multiframesequence

B3 Error  Mismatch of the recovered and computed BIP-8
HP-RDI     G1 (bit 5)=1, if an invalid signal is received in VC-4/VC-3
HP-REI     G1 (bits 1,2,3,4) = binary coded B3 errors

TU-AIS      All "1" in the entire TU incl. TU pointer
TU-LOP     8 to 10 NDF enable or 8 to 10 invalid pointers
LP-UNEQ  VC-3: C2 = all "0" for >=frames;
  VC-12: V5 (bits 5,6,7) = 000 for >=5 frames
LP-TIM     VC-3: J1 mismatch; VC-12: J2 mismatch
LP-SLM    VC-3: C2 mismatch; VC-12: V5 (bits 5,6,7) mismatch
BIP-2 Err  Mismatch of the recovered and computed BIP-2 (V5)
LP-RDI    V5 (bit 8) = 1, if TU-2 path AIS or signal failure received
LP-REI    V5 (bit 3) = 1, if >=1 errors were detected by BIP-2
LP-RFI    V5 (bit 4) = 1, if a failure is declared

Abbreviations : 

AU       Administration unit
HP       High path 
LOF    Loss of frame
LOM   Loss of miltiframe
LOP    Loss of pointer
LOS    Loss of signal
LP       Low path
OOF   Out of frame
REI     Remote error indication (FEBE)
RDI     Remote defect indication (FERF)
RFI     Remote failure indication
SLM   Signal label mismatch
TIM    Trace identifier
TU      Tributary unit
UNEQ  Unequipped
VC      Virtual Container
C        container





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