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OSN 500 550 580 V100R008C50 Alarms and Performance Events Reference 02

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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Downlink Signal Flow

Downlink Signal Flow

Overhead bytes are extracted and terminated in the higher order downlink signal flow.

Frame Synchronizer and Regenerator Section Overhead Processor

The regenerator section overhead bytes related to alarms and performance events are as follows:

  • Frame aligning bytes (A1 and A2)
  • Regenerator section trace byte (J0)
  • Bit error check byte (B1)

The alarm signal flow is as follows:

  • Receiving optical signals

    When an STM-N optical signal from an optical path enters the optical receive module in a line unit, the signal is converted into an electrical signal by the optical/electrical (O/E) conversion module.

    The signal is then transmitted to a frame synchronizer and a descrambler for processing.

    During this process, the O/E conversion module checks the signal.

    An R_LOS alarm is reported if one of the following faults is detected:
    • No optical signal is input.
    • The optical power is out of range.
    • The code type of the input signal is not the expected code type.

    When an R_LOS alarm is reported, the system inserts all 1s into the lower-level circuits. The SDH equipment returns to the normal state only when the optical receive module at the local NE detects two consecutive correct code patterns and no new R_LOS alarm is detected.

  • Monitoring the A1, A2, and J0 bytes

    After receiving an STM-N signal from the O/E conversion module, the frame synchronizer captures the frame alignment signal based on the A1 and the A2 bytes in the STM-N signal.

    Meanwhile, the frame synchronizer extracts the synchronization clock source of the line unit from the STM-N signal and sends it to the timing unit for clock locking.

    In normal cases, the value of the A1 byte is F6H, and the value of the A2 byte is 28H. If incorrect A1 or A2 values are detected in five consecutive frames, an R_OOF alarm is generated. If the R_OOF alarm lasts for more than 3 ms, an R_LOF alarm is generated and all 1s are inserted. If the frame aligning state lasts for more than 1 ms after the R_LOF alarm is generated, the equipment is restored to the normal state.

    The J0 byte is used to verify if both ends of a regenerator section are always connected to each other. The J0 byte transmitted by the transmit end must be the same as the J0 byte that the receive end is supposed to receive. Otherwise, the equipment reports a J0_MM alarm, indicating inconsistent trace identifiers.

    A descrambler descrambles all the bytes except the A1, A2, and J0 bytes and the two bytes that follow the J0 byte in an STM-N signal.

  • Monitoring the B1 byte

    The regenerator section overhead processor extracts and processes regenerator section overhead bytes in an STM-N signal. Of all the bytes, the B1 byte is the most important one.

    If the B1 byte extracted from an STM-N signal is not consistent with the BIP-8 computing result of the preceding STM-N frame, B1 bit errors occur.

    • If the number of B1 bit errors exceeds the threshold 10-3 (default value), a B1_EXC alarm is generated.
    • If the number of B1 bit errors exceeds the threshold 10-6 (default value), a B1_SD alarm is generated.

    When 10 consecutive RSSESs (a second in which block errors account for 30% is called an RSSES) are detected using the B1 type, an RSUAT performance event occurs. RSSES is short for regenerator section severely errored second.

The F1, D1-D3, and E1 bytes that are not related to alarms and performance events are transmitted to the SCC unit and the overhead unit.

Multiplex Section Overhead Processor

The multiplex section overhead bytes that are related to alarms and the performance events are as follows:
  • Automatic protection switching bytes (K1 and K2)
  • Multiplex section bit error monitoring byte (B2)
  • Multiplex section remote block error indication byte (M1)

The signal flow is as follows:

  • Monitoring the K1 and the K2 bytes

    Bits 6 to 8 in the K2 byte indicate a multiplex section remote failure.

    • If bits 6 to 8 in the K2 byte are 111, an MS_AIS alarm is generated and all 1s are inserted.
    • If bits 6 to 8 in the K2 byte are 110, an MS_RDI alarm is generated.

    The K1 type and bits 1 to 5 in the K2 byte are used to transmit the automatic protection switching (APS) protocol, and work with the SCC unit and the cross-connect unit to implement multiplex section protection (MSP).

  • Monitoring the B2 and M1 bytes

    If the B2 byte extracted from an STM-N signal is not consistent with the BIP-24 computing result of the preceding STM-N frame (all bits expect the regenerator section overhead), B2 bit errors occur.

    The M1 byte is used to check if an MS_REI alarm is reported. The M1 byte carries the number of incorrectly interleaved bit blocks that is detected using the B2 byte.

    • If the number of B2 bit errors exceeds the threshold 10-6 (default value), a B2_SD alarm is generated.
    • If the number of B2 bit errors exceeds the threshold 10-3 (default value), a B2_EXC alarm is generated.

    In the default status of the NE software, MSP switching is enabled and the B2_SD and B2_EXC alarms can trigger MSP switching.

    When 10 consecutive MSSESs are detected using the B2 byte, an MSUAT performance event occurs.

Pointer Processor and Higher Order Path Overhead Processor

The bytes that are related to pointer justification are H1, H2, and H3.

The bytes that are related to alarms and bit errors are as follows:
  • Higher order path trace byte (J1)
  • Signal label byte (C2)
  • Higher order path bit error monitoring byte (B3)
  • Path status byte (G1)
  • Multiframe position indication byte (H4)

The alarm signal flow is as follows:

  • Monitoring the H1 and H2 bytes

    The pointer processor interprets and justifies the pointer based on the H1 and H2 bytes in each AU-4. It implements frequency and phase alignment, and tolerates phase jitter and wander on the network. The pointer processor also locates each VC-4 and transmits it to the corresponding higher order path overhead processor. If the H1 and H2 bytes of the AU pointer are all 1s, an AU_AIS alarm is generated and all 1s are inserted. If the pointer values indicated by the H1 and H2 bytes are out of the specified range (0-782) and invalid pointers are received in eight consecutive frames, an AU_LOP alarm is reported and all 1s are inserted.

    If a positive AU pointer justification occurs, the number of PJCHIGHs of the multiplex section adaptation (MSA) increases by 1. If a negative AU pointer justification occurs, the number of PJCLOWs of the MSA increases by 1.

  • Monitoring the J1, C2, B3, G1, and H4 bytes

    The higher order path overhead processor processes higher order path overhead (HPOH) bytes in the received NxVC-4s.

    The mode for processing each byte is described as follows:

    If the J1 byte value detected is not the same as the preset value, an HP_TIM alarm is reported and all 1s are inserted.

    If the C2 byte value is 00, an HP_UNEQ alarm is reported and all 1s are inserted. If the C2 byte value detected is not the same as the preset value, an HP_SLM alarm is reported and all 1s are inserted.

    NOTE:

    For the Huawei OptiX Metro and OSN equipment, you can configure, on the NMS, all 1s to be inserted when an HP_TIM, HP_UNEQ, or HP_SLM alarm is generated. By default, all 1s are not inserted.

    Currently, the tributary unit group (TUG) is used as the payload structure in China. The preset C2 value corresponding to the TUG structure is 02.

    If the B3 byte extracted from the HPOH is not consistent with the BIP-8 computing result of the VC-4 signal of the preceding frame, B3 bit errors occur.

    If bit 5 in the G1 byte is 1, an HP_RDI alarm is reported. The value of bits 1 to 4 in the G1 byte determines whether an HP_REI alarm is reported. If the value of bits 1 to 4 ranges from 1 to 8, an HP_REI alarm is reported.

    When 10 consecutive HPSESs are detected using the B3 type, an HPUAT performance event occurs.

Other overhead bytes such as F3, K3, and N1 are reserved for future use.

Finally, the NxSTM-1 payloads are transmitted to the cross-connect unit for the cross-connection between the higher order path and the lower order path.

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Updated: 2019-01-21

Document ID: EDOC1100020975

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