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BUS_ERR on both XCM boards

Publication Date:  2018-07-20 Views:  455 Downloads:  0

Issue Description

The services on service board Slot 1 , board type SSN3EAS2 are down. Related alarms:





Handling Process

Analyzing this case starts with investigation of the alarms and alarm parameters.

Board in Slot 1 reported HARD_BAD alarm with parameter 0x0f, meaning that the component of the programmable logic device fails.  The alarm is cleared, but the services on slot 1 are down.

Analyzing the alarm parameters for BUS_ERR 0x00 0x01 0xb0 0x01 the conclusion is that the bus related to slot 1 reports alarm.

LPT_RFI was reported because of the VCAT_LOA alarm. Their meanings are:

The VCAT_LOA is an alarm indicating that the delay of the virtual concatenation is over long. This alarm occurs when the delay time of the timeslots bound to a VC trunk exceeds the time allowed by the virtual concatenation delay. The time allowed by the virtual concatenation delay depends on different board types.

The LPT_RFI is an alarm indicating the remote failure of the link state pass through (LPT). This alarm is reported when the LPT detects the failure of the remote port or the LPT service network. Symptoms of the LPT_RFI alarm : An alarm (such as the ETH_LOS, LINK_ERR, or LSR_NO_FITED alarm) is generated on the remote port or An alarm (such as the R_LOS, BIP_EXC, B3_EXC, TU_LOP, TU_AIS, VCAT_LOA, VCAT_LOM_VC12, VCAT_LOM_VC3, VCAT_LOM_VC4, LP_UNEQ_VC12, or LP_UNEQ_VC3 alarm) is generated on the LPT service network.


Both alarms are indicating a fault on slot 1.



Root Cause

Faulty service board SSN3EAS2.



1) cold reset the board in slot 1- no effect

2) replace the board in slot 1


Customer tried first to install the board in slot 2 and the effect was that the alarms reported by the XCM boards changed the parameters and indicated slot number 2 : 0x00 0x01 0xb4 0x02. Conclusion was that the SSN3EAS2 board is faulty and need to be replaced.