[OptiX OSN 8800] NEBD_XC_DIF alarm on TN52UXCH

Hello, everyone!

I would like to share with you an issue about NEBD_XC_DIF alarm on TN52UXCH cross-connect board housed in an OptiX OSN 8800 T32 equipment.

Description

The UXCH board is a cross-connect board and applies to enhanced and general OptiX OSN 8800 T32 subracks. It can cross-connect ODUk (k=0,1,2,2e,3,4, of flex) signals and VC-4 signals and performs packet switching of Ethernet services.

As below you can see the position of the UXCH board in the WDM system (ODUk cross-connetion):

The valid slots for the UXCH board are Slot 9 & 10, supports cross-connection 1+1 protection, provides 1+1 hot backup and 1+1 warm backup.

Regarding switching modes, supports the manual switching and auto switching. Also supports the non-revertitive switching.

Condition:

TN52UXCH cross-connect matrix data of the NE and SCC system control board being different. The NEBD_XC_DIF alarm is generated when the cross-connection data stored on the system control board is not consistent with that stored on a board supporting service cross-connections.

Symptom:

The NEBD_XC_DIF appear on NE. When you view an alarm on the network management system, select the alarm. In the Alarm Details field display the related parameters of the alarm. For details about each parameter, refer to the following table:

In our case, the alarm shows the following parameters:

Therefore, this parameters indicates an inconsistency of high-order cross-connect matrix data on the UXCH board housed in Slot 9:

Impact:

When the value of alarm parameter 3 is not 0x03, services are interrupted during service grooming or a warm reset on the board.

Severity:

Critical

Root Cause:

The possible causes of the NEBD_XC_DIF alarm are as follows:

Cause 1: The cross-connection data stored on the board is incorrect.

Cause 2: The cross-connection data stored on the system control board is incorrect.

Cause 3: Multiple subracks are configured in master-slave mode and SDH boards are present in the slave subracks.

In this case, the cause of the NEBD_XC_DIF alarm is "The cross-connection data stored on the system control board is incorrect".

Solution:

The possible solutions for our case (Cause 2) are the following:

1) If the alarm persists, perform a warm reset on the board related to service cross-connections on the NMS.

2) If the alarm persists, perform a warm reset on the system control board on the NMS.

Due to the risk of service interruption when performing a warm reset, a cutoff window is scheduled.

Therefore, a warm reset is performed on the UXCH cross-connection board in Slot 9, the switch to the UXCH board in Slot 10 occurs and the alarm disappears.

Since the UXCH cross-connection boards on Slot 9 & 10 are in the "hot backup 1+1" configuration, the operation of changing the active / standby state is carried out from NMS, leaving the UXCH board on the Slot 9 as "active".

Issue solved!!

References:

    - HedEx

BR