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Description of the problem
One day, an operator reports that an EPL service from the N2EFS0 board of a Huawei OSN3500 device to the EFS board of a 155622H device is interrupted, and the VCTRUNK of the OSN7500 corresponding to the service reports the ALM_GFP_dLFD alarm. 155622H devices have no abnormal performance or alarms.
Processing
(1) Carefully check the encapsulation protocol and related parameters of the single boards at both ends of the service, and the corresponding parameters of the two network elements are consistent.
(2) Check whether the number of uplink or downlink time slots bound to the corresponding VCTRUNK of this station and the opposite station is consistent, and the number of time slots is consistent after checking.
(3) Check whether there are optical power problems and SDH-side BERs on the SDH service side of the line, and the SDH performance is normal, and there are no optical power problems or BERs.
(4) Check the time slots bound by VCTRUNK for the existence of BIP_EXC, BIP_SD, B3_EXC and B3_SD error code alarms, and no such alarms are found in the equipment at both ends.
(5) Replace the line time slot, the fault remains.
(6) Replace the virtual time slots of the data boards of the equipment at both ends, and the problem persists.
(7) Replace the VCTRUNK of OSN7500 device, the alarm disappeared and the problem was solved. Later, after the company returned for repair, it was found that the poor contact between a chip on the single board and the main PCB led to the failure of part of the function of the chip, which led to the failure of individual VCTRUNK.
Root cause
Poor contact between a chip on the single board and the main PCB leads to partial failure of the chip, thus causing individual VCTRUNK to be inoperable.
Solution
Replace the veneer.
