2021-01-15 0

How to deal with ONT failure due to mismatched optical modules of Huawei OLT?

Situation 1:

Trouble phenomenon: After the voice call is used for a period of time, there is a problem that the called party is normal, but the calling party cannot make outgoing calls. There is no movement after the caller picks up the phone and dials the number during the fault. This problem occurs intermittently, and often occurs again after a few days of normal operation. There is a historical alarm of MG interface failure on the MA5800

Process
  1. After replacing the equipment, there are still problems, and the equipment problems are preliminarily eliminated.
  2. When there is a problem, use DBWIN to trace the signaling, but the signaling of the reported number is not seen, and the signaling of off-hook and on-hook of the user port can only be seen in the whole process.
  3. Since it is connected to the B manufacturer’s softswitch and uses the global digitmap, it is suspected that there is a problem with the digitmap on the device. Use the DBWIN command to query the global digitmap on the current device. It is found that there is no digitmap information on the device when the problem occurs.
  4. Perform a reset on the MG interface of the device, and track the signaling during the startup process after the MG interface is reset through DBWIN. In the whole reset process, except for the signaling in the figure below, other signaling is normal. At this time, it is suspected that either the softswitch has not issued the digitmap, or the softswitch has issued the digitmap but the MA5800 has not received it.
  5. The PING test on the softswitch on the MA5800 found that the PING packet reached more than 300 bytes and it would not work. Switching to the MA5800 to test the softswitch PING is the same result.
  6. The broadband service and voice service on the MA5800 are separately uplinked, and the broadband service has never been abnormal. Query the interface status of the uplink board of the MA5800, and find that the light reception power of the voice service uplink port and the broadband service uplink port are quite different, and the light reception of the voice service uplink port is relatively weak.
  7. After adjusting the voice uplink optical path of the MA5800, the service returns to normal.
Root cause
  1. Equipment failure
  2. There is a problem with the number map issued by the softswitch
  3. Other docking issues
Situation 2:

Fault phenomenon: ONT equipment connected to MA5800 goes online and offline from time to time, and business is interrupted from time to time. After restarting the ONT, the fault persists after a period of normal operation.

Root cause
  1. The quality of the optical path is not good, and the optical power is between the critical values;
  2. ONT PON port failure;
  3. Quality problems of the optical splitter;
  4. OLTPON port failure;
  5. The OLT and ONT optical modules do not match.
Process
  1. Measure the received light on the ONT side with an optical power meter and find that it is about -15dB, which meets the deployment requirements and eliminates optical path problems.
  2. Replace the normal ONT equipment for testing, and the fault persists. Remove the ONY PON port problem.
  3. If the splitter port is replaced, the fault persists, and the faulty ONTs are not all under the same splitter. Remove the splitter problem.
  4. For the OLT, because the ONT that has failed belongs to different PON ports of different PON boards of the OLT, the problem of the PON port of the OLT equipment is temporarily eliminated.
  5. Check the operating status of the ONU equipment on the OLT equipment. It is found that the ONU of the GPON is reported by the ONT to the OLT, and the PON board on the OLT equipment is an EPBC single board, which can only process the EPON protocol. The optical module type issued by the ONT does not match the optical module type on the OLT equipment side. The OLT side is EPON and the ONT side is GPON, which causes problems.
  6. Change the PON board of the OLT equipment to a GPBC single board for testing. The equipment is operating normally and the problem is eliminated.
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