20248 Loss of Tributary Signals (LOS)

Description

There is no signal input on this tributary.

Attribute

Alarm ID Alarm Severity Alarm Type
20248 Major Fault

Parameters

ID Name Meaning
1 Subrack No.

Subrack No.
2 Slot No.

Slot No.
3 Cpu No.

CPU No.
4 Tributary Unit No.

0 - 62(for E1 mode), 0 - 83(for T1 mode).
5 Site No.

The IDs of all sites whose OMLs are on the faulty E1/T1. If BTS are cascade connected,a maximum of 4 sites are shown.Only Abis E1/T1 alarm has this parameter.
6 Site Name

The Names of all sites whose OMLs are on the faulty E1/T1. If BTS are cascade connected,a maximum of 4 sites are shown.Only Abis E1/T1 alarm has this parameter.
7 Alarm Attribute

0=Normal, Alarms period are longer than the Transient Threshold.

1=Transient Count, The times and the period of the alarms whose periods are shorter than the Transient Threshold are summed up. If the sum result is longer than the Alarm Occurrence Period Threshold or Alarm Occurrence Times Threshold, an alarm so called Transient Count Alarm is triggered. Because Transient Count Alarm is based on accumulative result, the recovery of the alarm may occur at least one Summing Cycle later. The Summing Cycle can be query by MML "LST STATSLDWIN".

Impact on the System

The service over this tributary might be interrupted.

System Actions

  • Handling of the active board in the active/standby operation mode: Perform the switchover if the standby is ready for the operation.
  • Handling of the standby board in the active/standby operation mode: None.
  • Handling of the board in the Independent operation mode: None.

Possible Causes

  • The optical fiber of this link is not securely installed.
  • The receiving mechanism over this link of the local equipment is faulty.
  • The transmitting mechanism over this link of the peer equipment is faulty.
  • The transmission link is faulty.

Procedure

  1. Secure the optical fiber at the local and peer ends, and then check whether the alarm is cleared.

    Y => The alarm is cleared. The alarm handling is complete.

    N => The alarm persists. Go to 2.

  2. Reset the local board and wait for the startup of the board, and then check whether the alarm is cleared.

    Y => The alarm is cleared. The alarm handling is complete.

    N => The alarm persists. Go to 3.

  3. Contact the maintenance personnel at the peer end to loop back the peer end toward the local end. Check whether the alarm is cleared.

    Y => The alarm is cleared. It indicates that the board at the peer end is faulty. Ask the personnel at the peer end to clear the fault. The alarm handling is complete.

    N => The alarm persists. Go to 4.

  4. Contact the transmission personnel and check whether the transmission is normal.

    Y => Go to 5.

    N => The alarm handling is complete.

  5. Replace the local board and wait for the startup of the board, and then check whether the alarm is cleared.

    Y => The alarm is cleared. The alarm handling is complete.

    N => The alarm persists. Please contact Huawei Customer Service Center.

Parent topic: BSC Alarm Reference
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