MC-A217 An IN_PWR_LOW Alarm Is Reported After an Optical-Layer ASON Service Is Configured on the ASON OptiX OSN 6800 NE
An IN_PWR_LOW alarm is reported after an optical-layer ASON service is configured on the ASON OptiX OSN 6800 NE.
During expansion of an ASON OptiX OSN 6800 NE at an office, the opposite NE reports an IN_PWR_LOW alarm after an ASON service is configured on the ASON NE.
Figure 1 shows how the fibers inside the NE are connected.
When an ASON service is configured, a fiber connection and an optical cross-connection are created from the OTU board to the FIU board. After the optical cross-connection is created, the OPA function automatically sets the attenuation of the VA4 board to achieve automatic power adjustment of the WDM system.
After a field inspection, it is found that the OPA function sets the attenuation of the VA4 board to a great value, thus resulting in excessively low output optical power.
- Verify that the insertion loss of the boards (602-NS2 and 509-OBU1 in the preceding figure) between the OTU and OA boards and the insertion loss of 506-M40 are lower than 6.5 dB. This meets the attenuation requirement as the attenuation margin for the boards between the OTU and OA boards is 20 dB.
- Check fiber jumpers and find no exception. Thus, rule out the possibility that fiber jumpers are of bad quality.
- Check the output optical power threshold of the OTU board and the rated optical power of the OA board and find the settings are correct.
- Find that a mechanical VOA is installed between the OTU and VA4 boards and the attenuation of the VOA is relatively high. This is why the optical power from the OTU board to the OA board is low and the opposite NE reports an IN_PWR_LOW.
- Further analyze the wavelengths sent to the same M40 board and find that some channels are configured with mechanical VOAs but some are not. In addition, the attenuation values of the mechanical VOAs are different. In this case, the optical power of all the wavelengths cannot be flattened even though OPA adjustment is successful.