Alcatel 1660SM Technical Handbook page 552

– MSA block: pointer detection process.
The pointer interpreter can detect two defect conditions:
•
Loss Of Pointer (LOP);
•
AU–AIS.
If either of these defect conditions are detected, then a logical all–ones (AIS) signal is generated
– HPT block:
•
B3: The error monitoring byte B3 is recovered. BIP–8 is computed for the VC–4 frame. The
computed BIP–8 value for the current frame is compared with the recovered B3 byte from the
following frame.
The process for detecting excessive errors and signal degrade is described in
Reccomandation. G.806.
B3 Errored Block event happened during the last second of VC–4 #0 are reported in "Alarms
and controls" block register.
B3 Errored Block of VC–4 #0 are also used to calculate total number of errored block.
•
G1[1–4]: The REI is recovered and the derived performance primitives is reported for
processing.
•
G1[5]: The RDI defect is processed as described in ITU–T Reccomandation. G.806.
•
C2: Unequipped defect is detected (refer to G.783)
– HPA block:
The following function are performed:
•
C2 extraction: Byte C2 is recovered from VC–4 #0. If a dPLM is detected (see ITU–T G.806),
then it will be reported in an "Alarms and controls" block register.
•
H4 extraction: Multiframe indicator is derived from the H4 byte. The received H4 value is
compared to the next expected value in the multiframe sequence. The H4 value is assumed to
be in phase when it is coincident with the expected value. If several H4 values are received
consecutively not as expected but correctly in sequence with a different part of the multiframe
sequence, then subsequent H4 values will be expected to follow this new alignment. If several
H4 values are received consecutively not correctly in sequence with any part of the multiframe
sequence, then a loss of multiframe (LOM) event is reported. When several H4 values have
been received consecutively correctly in sequence with part of the multiframe sequence, then
the event will be ended and subsequent H4 values will be expected to follow the new alignment.
•
extraction of payload from packetsand process the heaer content
•
automatic client based band and latency preset
•
client clock adaptation
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3AL 91669 AA AA
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ITU–T
550 / 674