Deleting PQ1 Boards on NM Fails

When you delete the PQ1 boards on the T2000, you also need to delete the corresponding interface boards. Otherwise, deleting the tributary boards may fail.

Product

OptiX OSN 2500

Fault Type

PDH_Access_Unit

Symptom

On the OptiX OSN 2500, one PQ1 board is inserted in slot 13, which is protected by the other PQ1 board in slot 5. The PQ1 board in slot 13 needs to be deleted. Firstly, the TPS protection group between the PQ1 boards in slot 13 and slot 5 is deleted and then the PQ1 in slot 5 is deleted. When the PQ1 board in slot 13 is deleted, however, the T2000 returns a prompt indicating that the service source cannot be released and the error code is “39492”. The NE software is 5.27.01.16 and the board software of the PQ1 is 1.17.

Cause Analysis

You may fail to delete the PQ1 board on the T2000 in the following cases:

  • The PQ1 board may belong to a TPS protection group.
  • The PQ1 board is configured with services.
  • The interface board corresponding to the PQ1 board is not deleted.

Procedure

  1. Check whether the PQ1 board belongs to the TPS protection group. It is found that the TPS protection group is already deleted before the PQ1 board in slot 13 deleted.
  2. Check the services on the PQ1 board in slot 13. It is found that the PQ1 board is not configured with any services or paths.
  3. It is found that the PQ1 board in slot 5 does not have the corresponding interface board, and can be deleted. Then, Check the relevant information. It is found that the PQ1 board in slot 13 has two D12S interface boards in slot 17 and slot 18. Delete the two interface boards, and then the PQ1 board in slot 13 is successfully deleted.
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Determine Whether the Type and Connections of the DCM Are Proper When the OTU_LOF, R_OOF, R_LOF, and BEFFEC_SD Alarms Are Reported Discontinuously on the WDM Side of LWF Board

Determine whether the type and connections of the dispersion compensation module (DCM) are proper according to the insertion loss between the TDC and the RDC optical interfaces on the OAU when the OTU_LOF, R_OOF, R_LOF, and BEFFEC_SD alarms are reported discontinuously on the WDM(such as OSN6800, OSN8800) side of LWF board.

Product

OptiX BWS 1600G

Fault Type

Dispersion Abnormality

Optical Transponder Unit

OTU_LOF

R_LOF

R_OOF

BEFFEC_SD

Symptom

During the deployment commissioning of the OptiX BWS 1600G system of a certain site, if is found that the OTU_LOF, R_OOF, R_LOF, and BEFFEC_SD alarms are generated discontinuously on the WDM side of certain LWF boards with the AFEC function. In addition, the BER before correction is 1, and the services are unavailable. In the system, only four wavelengths are added. And no regeneration OTU board is configured in the pass-through OTM station, which means that the west and east mux/demux boards are connected directly by using fiber jumpers.

Cause Analysis

The causes may be as follows:

  • Optical power
  • Signal-to-noise ratio (SNR)
  • Failure of the LWF board
  • Dispersion compensation

Procedure

  1. Check whether the optical power on the entire network is normal. The optical power of multiplexed wavelength signals and the received and launched optical power of the board are found normal.
  2. Use an optical spectrum analyzer (OSA) to measure the OSNR in each faulty channel. It is found that the OSNR is above 20 dB. This is normal for either the LWF boards with the AFEC function or common LWF boards.
  3. Replace the west and east LWF boards and set the FEC Working Mode to be the same. The fault persists.
  4. The preceding steps exclude the possibility that the fault is caused by the LWF boards, the optical power, or the OSNR. Thus, the dispersion compensation may be improper. After recalculation, it is confirmed that the dispersion compensation value in the design is proper.
  5. We suspect that the DCMs on the network are improperly connected or the types of the customer fiber on the network are inconsistent with the fiber types specified in the design document. After confirmation with the customer, it is found that the customer fiber types meet the design requirements.
  6. To further determine whether the dispersion is improper, adjust the dispersion compensation range of a single wavelength of the faulty board by increasing or decreasing the dispersion compensation at the receive end. To increase the dispersion compensation, configure a DCM module between the D40 and LWF board at the receive end of the single wavelength; to decrease the dispersion compensation, replace the DCM module on the line side at the receive end with another DCM module with smaller compensation value. During the test, it is found that the dispersion of the single wavelength is over-compensated.
  7. On the network, only a small number of wavelengths are added, and no regeneration OTU board is used. Hence, it is difficult to narrow down the range in which the dispersion compensation is improper.
  8. On the T2000, query the difference between the optical power at the TDC optical interface and the optical power at the RDC optical interface on the OAU board where the DCM module is configured. Focus on the sites where the actual optical power difference differs greatly from the typical insertion loss of the DCM module, especially the sites where the OAU board is used at the receive end in the east and west directions but the DCM modules in the two directions are different. During the deployment, it is probable that the DCM modules are connected improperly, which results in over-compensation in one direction but under-compensation in the other direction.
  9. During the check, it is found that the insertion loss between the TDC and RDC optical interfaces on the OAU board in slot 1 at a certain OLA station is 5.6 dB, and the insertion loss between the TDC and RDC optical interfaces on the OAU board in slot 12 is 6.4 dB. According to the design requirements, the OAU board in slot 1 should be configured with E-type DCM module, and the OAU board in slot 12 should be configured with the C-type DCM module. That is, the insertion loss in the case of the OAU board in slot 1 should be greater than the insertion loss in the case of the OAU board in slot 12. The symptom indicates that the DCM modules in the east and west directions of the OLA station are configured reversely. After a check on site, it is found that the connections of the DCM modules reverse the connections specified in the design document. After the DCM modules are connected properly, the system performance becomes normal again, and the BER before error correction of the LWF boards on the entire network is restored to 0.

Result

The problem is solved after the operation is finished as the requests.

During the deployment of WDM equipment, the west and east DCM modules in the OLA station or the back-to-back OTM station are connected reversely due to design or artificial factors. In such cases, probably over-compensation of dispersion occurs in one direction, while under-compensation of dispersion occurs in the other direction. As a result, the system fails to function. Therefore, it is vital to check the types and connections of the DCMs at all stations during the deployment of long haul WDM projects. The types and connections of the DCMs will also affect the system expansion.

During the deployment or expansion of a WDM system, locate the fault by increasing or decreasing the dispersion compensation at the receive end if you suspect that the dispersion compensation is improper. This method enables you to determine whether the current system experiences over-compensation or under-compensation of dispersion. This facilitates you to solve the problem.

Question About the Extended ECC of WDM NEs

How many NEs at a site can interconnect with each other using automatic extended ECC?

Fault Type

ECC

NE Offline

Symptom

Many NEs in a certain site interconnect with each other using automatic extended ECCs. As a result, many NEs that are connected to each other using automatic extended ECC are unreachable to the T2000.

Cause Analysis

When extended ECC communication is established based on Ethernet, the number of NEs that are interconnected with each other through automatically extended ECC must be below seven (inclusive). In the case of manually extended ECCs, the number of clients connected to a server must be below seven (inclusive). Each of the clients, however, can function as a server and connect to other clients. Hubs or routers can be cascaded. The number of cascaded hubs or routers is subject to the network scale. This basic principle is applicable to all products and related to the specific platform.

In the case of the OptiX Metro 6100 and OptiX BWS 1600G, ETHERNET1 and ETHERNET2 in the interface area of a subrack are cascaded for communication. The number of cascaded NEs should be equal to or less than eight.

Reference Information

None.

The PMU Reports the THUNDERALM Alarm

The PMU reports the THUNDERALM alarm.

Fault Type

Power Supply

THUNDERALM

Symptom

The PMU of the OptiX Metro 6100 equipment reports the THUNDERALM alarm.

Cause Analysis

The fuse for a protection indicator on the DPFU is blown out. According to the definition of the parameters of the alarm, the format of the alarm is as the following:

  • PARA1 PARA2 PARA3 PARA4 PARA5
  • 0x** 0xff 0xff 0xff 0xff
The definition of the PARA1 is as the following:

  • 0x11: indicates that the level-1 lightning protection indicator for the DPFU in channel 1 is unlit.
  • 0x12: indicates that the level-2 lightning protection indicator for the DPFU in channel 1 is unlit.
  • 0x21: indicates that the level-1 lightning protection indicator for the DPFU in channel 2 is unlit.
  • 0x22: indicates that the level-2 lightning protection indicator for the DPFU in channel 2 is unlit.

In the normal configuration, current is input from channel A of the DPFU in channel 1 and channel B of the DPFU in channel 2.

The level-1 lightning protection indicator is unlit is equivalent to that fuse 14 is blown out.

Likewise, the level-2 lightning protection indicator is unlit is equivalent to that fuse 5 is blown out.

Each lightning protection alarm level corresponds to a specific fuse class for alarm analysis and troubleshooting.

Procedure

  1. Test the lightning protection fuses for the DPFU.
  2. When you install the fuses, unscrew the four screws on the DPFU. The lightning protection fuses F14 and F5 are the two fuses correspond to the alarm indication. In the case of blow-out of a fuse, a backup fuse is available on the DPFU.

Reference Information

None.

The WXCP Protection Configured for the LOG Board Is Invalid

The WXCP protection configured for the LOG board is invalid due to the configured attributes of the board.

Fault Category

Protection

Symptom

The LOG board is configured with the correct WXCP protection.

During a protection switching test, services are interrupted because there is no protection channel to which the services can be switched; however, no alarms are reported to the T2000.

Check whether the protection configuration is correct.

If you delete the protection group and then configure a new one, the fault persists.

Cause Analysis

The WXCP protection configured for the LOG board is invalid due to the configured attributes of the board.

Procedure

  1. Check the LOG board of the protection group.
    1. In the NE Explorer, select the LOG board to be checked.
    2. Select Configuration > WDM Interface from the Function Tree.
    3. Click the Advanced Attributes tab.
    4. Check whether the Max Packet Length is 9800.
  2. In this case, set the value of this parameter to 1511.
  3. Because the value of the parameter cannot be changed, set the LOG board.
  4. After the LOG board is reset, the value of the parameter is displayed as 9800.
  5. Test whether the fault is cleared. If the fault is cleared, the WXCP protection becomes valid.

Reference Information

None.

The Input Optical Power of the OTU Board Is Abnormal Due to a Fault of the OPU Board

The input optical power of the OTU board is abnormal due to a fault of the OPU board.

Fault Category

Optical Power Abnormity

Optical Amplifier Unit

Symptom

In a single-channel ring network, the input optical power of an OTU board drops from 0 dBm to -7 dBm, -15 dBm, or -62 dBm.

This ring network bears the SDH service and is configured with the multiplex section protection (MSP).

Cause Analysis

The launched optical power of the opposite OTU is abnormal, or the line amplifier unit is faulty.

Procedure

  1. By checking whether there are abnormal alarms against the input optical power of the opposite OTU board, you can find that the parameters of the opposite OTU board are proved normal. This indicates that the launched optical power of the opposite OTU is normal.
  2. The input and output optical power of the opposite amplifier board are also checked normal.
  3. The input and output optical power of the local amplifier board, however, are checked abnormal. The input optical power of the local amplifier board is constant, whereas the output optical power of the local amplifier board is abnormal. This indicates that the local amplifier board is faulty.
  4. After you replace the local amplifier board, the system is restored.

Reference Information

  • When you find that the output optical power of the local OTU is abnormal, check the following items:
    • Input and output optical power of the opposite OTU board
    • Input and output optical power of the opposite amplifier board
    • Input and output optical power of the local amplifier board
  • If the anomaly of optical power occurs at random, perform the following steps:
    • Check whether any fiber jumper is loose or bent.
    • Clean the fibers and connectors.
    • Perform an optical time domain reflectometer (OTDR) test under the customer’s consent.

How to Handle the J0_MM Alarm on the LWM

How to handle the J0_MM alarm on the LWM.

Product

OptiX Metro 6100

OptiX Metro 6040

Fault Type

Optical Transponder Unit

JO_MM

Symptom

The ANT20 analyzer is used to test an STM-16 link with two LWM boards. One LWM connects to the analyzer and the other is looped back. The traffic is normal but the LWM reports the J0_MM alarm. Check on the J0 transmitted by analyzer shows that the J0 byte was set to 11. Check on LWM -> Configuration/WDM Overhead Management/SDH Overhead shows that J0 to be transmitted and J0 to be received (displayed in hex) are both 11.

Cause Analysis

Verify the SDH overhead in text mode not just in hexadecimal format.

Procedure

  1. Check on the J0 trace identifier on analyzer shows that the test is in process.
  2. Checked on the SDH overhead of the LWM (displayed in text) shows that the J0 received is indeed “text”, but the J0 to be received is blank.
  3. The J0 to be received (displayed in text) is changed to be tested and the alarm is cleared.

Reference Information

None.