Description of the problem

Huawei OSN3500 equipment carries the E1 transmission of eight STM-1s from the RNC to the NodeB on the wireless side. In the OSN3500 configuration, the line side is interfaced with the RNC using the N2SLO1, and the branch side is interfaced with the NodeB using the N2PQ1. Suddenly, on a certain day, the STM-1s of the six channels do not work, resulting in service interruption.

Alarm Information

TU_AIS alarms are reported on N2PQ1 corresponding to the 6 channels on OSN3500 and HP_TIM on N2SLO1

Processing

After the previous analysis, it is due to the fact that OSN3500 network elements enable HP_TIM alarm as the trigger condition of TU_AIS alarm, and turn off HP_TIM as the trigger condition of TU_AIS, the TU_AIS alarm disappears, and the service is resumed.

In the network element manager path-〉Alarm-〉Qos Alarm-〉AIS Insertion switch

Command line operation is as follows:

:cfg-get-alm2aisr1:0

ALM2AIS-STATE

ALARM-EID AIS-ENABLE

roof enable

b1exc enable

b1sd enable

b2exc enable

b2sd enable

b3exc enable

b3sd enable

hpslm enable

hpuneq enable

hptim enable

lptim enable

lpslm enable

lpuneq enable

bipexc enable

Total records :14

:cfg-set-alm2aisr1:hptim,disable

Root cause

There are several reasons for this from the analysis of the alarms obtained:

The first is because we have a problem with the service configuration on the equipment side. After the inner loop back to the optical port of N2SLO1 corresponding to the interrupted service, we found that the TU_AIS of the corresponding N2PQ1 single board disappeared, and at the same time on the DDF side, the corresponding E1 signals are sent and received normally, so we rule out the problem of the service configuration;

Secondly, the wireless NRC side has problems with OSN3500 docking, after doing inner loopback and outer loopback on the NRC side and outer loopback with N2SLO1 docked with our OSN3500, the NCR and OSN3500 alarms are restored to normal, ruling out the optical path of the docking equipment and hardware problems;

The third is to suspect that OSN3500 and wireless NRC docking overhead byte matching problems, after checking the N2SLO1 reported HP_TIM alarm, go to check the N2SLO1 optical port J1 byte send and receive status, with Navigator command line query send and receive the parameters set and the actual receipt of the information is inconsistent, and at the same time to confirm that in the NRC side of the J1 overhead setting is null, after querying TU_TIM, the NCR and OSN3500 are all back to normal. null, after querying the triggering conditions of TU_AIS alarm, it is found that OSN3500 network element enables HP_TIM alarm as the triggering condition of TU_AIS alarm, and the problem is localized.

Suggestion and Summary

For OSN3500 network elements, other alarms will trigger the TU_AIS alarm, and for some scenarios, it is recommended that the conditions for triggering the TU_AIS alarm should be shielded according to the actual situation to avoid unnecessary service interruptions.

The technical information and SDH equipment troubleshooting procedures in this chapter are collected and organized by Shenzhen Optical Transmission Network Technology Co. Our company specializes in the sale of Huawei SDH optical transmission equipment,SDH transmission equipment.