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Knowledge Base

The Protection EMS4 Board in a BPS Protection Group Constantly Reports the ETH_LOS Alarm After the EMS4 Board Is Configured with the BPS Protection

Publication Date:  2012-07-25  |   Views:  174  |   Downloads:  0  |   Author:  SU1001435750  |   Document ID:  EKB0000471606


Issue Description

After the N1EMS4 board is configured with the BPS protection through the FE electrical ports, the ports on the protection board report the ETH_LOS alarm all the time. In this case, forced switching can be performed successfully but switching triggered by disconnecting the network cable of the working path fails.

The NE software is of V100R008. 

Alarm Information


Handling Process

1. Field engineers checked and found that the working mode of the port on the working board was 100MFULL. The BPS protection was supported only in 100MFULL mode for the 100 Mbit/s electrical ports.

2. The BPS protection was performed in master and slave modes. In master mode of the BPS protection, the protection port on the board disabled its transmit function. Consequently, the LINK_ERR or ETH_LOS alarm was reported by the opposite station. The protection port at the opposite station, however, did not disable the transmit function. Therefore, the working and protection ports were in LINK_UP state, and the working and protection boards were available.

3. In slave mode of the BPS protection, the protection port on the board was enabled all the time. When switching occurred, the working port on the board was disabled for three seconds and then was enabled.

4. It was confirmed that the OptiX OSN equipment was interconnected with the Huawei BSC the CDMA network. The BPS protection for the FE electrical ports was performed only in master mode for the OptiX OSN equipment of V100R008. In BPS master mode, the protection port was disabled all the time. Consequently, the ETH_LOS alarm was reported by the port on the interconnected BSC. After receiving the ETH_LOS alarm, the BSC disabled its transmit function. As a result, the protection board on the transmission equipment constantly reported the ETH_LOS alarm and the board was unavailable all the time.

5. Upgraded the OptiX OSN equipment from V100R008 to V100R009C04 to support the BPS slave mode of the FE electrical ports.  

Root Cause

1. The interconnected equipment is faulty.

2. The settings are incorrect.

3. The version number is incorrect. 


This problem occurs when the OptiX OSN equipment is interconnected with Huawei BSC on the CDMA network. If the OptiX OSN equipment is interconnected with the equipment from other vendors, this problem can also be resolved according to the preceding methods.