21002 Broken LAPD Link

Description

This alarm is reported when the LAPD link cannot receive any message from the BTS or the PCU at the peer end.

Attribute

Alarm ID	Alarm Severity	Alarm Type
21002	Critical	Fault

Parameters

ID	Name	Meaning
1	Link No.	Number of the broken link
2	Subrack No.	Number of the subrack where the broken link is located
3	Slot No.	Number of the slot where the board carrying the broken link is located
4	Port No.	Number of the port carrying the broken link
5	Trx ID	TRX ID to LAPD Link
6	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 faulty E1 cable or the faulty peer end will disrupt the services.
If the network is not stable, the system will automatically restore to the normal state.

System Actions

The system reports the alarm and the LAPD link is switched over to the state ready for link setup. A request for link setup is sent to the PCU or the BTS at the peer end every five seconds. After the E1 cable is normal or the network is stable, the system sends a recovery alarm within five seconds. The LAPD link restores to the normal state.

Possible Causes

The network is unstable and the intermittent link is caused.
The E1 cable is faulty.
The BTS or the PCU at the peer end is faulty.

Procedure

Wait for about one minute, and then observe whether the alarm is cleared automatically in the Browse Alarm window on the LMT.
Y => The alarm is cleared. The alarm handling is complete.
N => The alarm persists. Go to 2.
Tighten the E1 cables, 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.
Change the E1 cables, and then check whether the alarm is cleared.
Y => The alarm is cleared. The alarm handling is complete.
N => The alarm persists. Go to 4.
Notify the maintenance personnel at the peer end to check whether the BTS or the PCU at the peer end is faulty.
Y => Rectify the fault. The alarm handling is complete.
N => Please contact Huawei Customer Service Center.