Differences of the MUT_LOS and R_LOS alarms on OA boards of WDM devices

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Question:
On Huawei WDM devices, why some OA boards report the R_LOS alarm whereas some OA boards report the MUT_LOS alarm when they do not receive any light or the receive optical power is excessively low?
Analysis:
None
Answer:
When the OA boards (such as WPA, WBA, and WLA) on 320G devices do not receive any optical signals, the R_LOS alarm is reported. When the OA boards (such as OPU, OBU, and OAU) on 1600G, 800G, and 400G devices do not receive any optical signals, the MUT_LOS alarm is reported.
Suggestion and conclusion:
The R_LOS alarm is used to indicate the loss of input optical signals on a single wavelength of a board such as OTU. The MUT_LOS alarm is used to indicate the loss of multiplexed optical signals on a board such as M40, D40, OAU, OBU, or OPU. It is inaccurate that the R_LOS alarm is reported when OA boards do not receive any optical signals. Therefore, the R_LOS alarm is canceled for new OA boards. When developing new 1600G, 800G, and 400G WDM systems, Huawei adjusts the alarm that is reported when OA boards do not receive any optical signals. To be specific, the OA boards report the MUT_LOS alarm when receiving no optical signals.

Other related questions:
Types and specifications of OA boards for WDM networks
Fiber amplifiers or OA boards amplify optical signal power to extend the signal transmission distance. The product documentation has described the types and specifications for fiber amplifier boards. For details, see the related topics in the product documentation.

Whether the FIU board reports the MUT_LOS alarm
Yes, it does.

Conditions for SFIU boards to report MUT_LOS alarms
Question: When no service is deployed on new TN11SFIU boards at a site, some of the new SFIU boards report the MUT_LOS alarm whereas the others do not. Analysis: The SFIU boards do not detect optical power and do not report the MUT_LOS alarm alone. OA boards are required to produce the MUT_LOS alarms, and the conditions to produce the MUT_LOS alarms are as follows. Answer: The conditions are: 1. There are logical fiber connections. 2. The OA board in the receive direction reports an MUT_LOS alarm. 3. The OA board in the transmit direction does not report any MUT_LOS alarms. 4. The OSC_LOS alarms are ignored.

Hardware differences between LWC boards on LH WDM devices
Question: SSE1LWC and SSEM1LWC are present in technical documents. Do they have any differences? Answer: SSEM1LWC is a configuration board and SSE1LWC is a finished board. The two boards can be considered as the same board in most cases, and even SSEM1LWC is regarded as SSE1LWC in communication. However, you need to differentiate them in spare parts application and rectification, because you need to provide the BOM numbers of multiple configuration modules when applying for a configuration board, but you need to provide only one BOM number when applying for a finished board.

Causes of an R_LOS alarm
Client-side cause 1: On the optical connector of the local board, the pigtail is not connected, or is loosely or incorrectly connected. Client-side cause 2: The line attenuation is too large, or a fiber cut occurs on the line. Client-side cause 3: The board that reports the alarm is faulty. Client-side cause 4: If the board reporting the alarm is a 40G or 100G board, at least one wavelength has been missing from the receive end of the board. WDM-side cause 1: On the optical connector of the local board, the pigtail is not connected, or is loosely or incorrectly connected. WDM-side cause 2: The line attenuation is too large, or a fiber cut occurs on the line. WDM-side cause 3: The board laser at the peer site is turned off. WDM-side cause 4: A fault occurs on the transmit module of the board at the peer site or on the receive module of the board at the local site.

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