The TN11OAU101 at the Transmit End Reports the MUT_LOS Alarm

The TN11OAU101 at the transmit end reports the MUT_LOS alarm because the optical attenuation

of the M40V board is not adjusted.

Product

OptiX OSN 6800

Fault Type

Service Interruption

Automatic Power Equilibrium (APE)

Optical Amplifier Unit

MUT_LOS

Symptom

At the ROADM station consisting of the OptiX OSN 6800 V1R2, the signal flow in the wavelength

add direction is as follows: L4G->M40V->WSM9->OAU->FIU. After the internal logical fiber

connections are complete at the NE, create the single-station optical cross-connections and select

the automatic optical power adjustment function. Then, the T2000 prompts that the creation is

successful. The OAU board, however, reports the MUT_LOS alarm. No alarm is generated on

other boards.

Cause Analysis

The OPA supports only the WSD9, WSM9, RMU9, and ROAM boards. In the case of other boards

supporting the setting of attenuation (VA1/M40V/D40V), the OPA does not set the attenuation.

Thus, you need to set the attenuation. During the calculation, OPA regards the attenuation as

zero (0) and the changes in the attenuation of the boards does not trigger the re-adjustment by

the OPA.

By default, the VA1, M40V, and D40V take the maximum attenuation for each channel. Hence,

when the OPA function is started, the light from the L4G does not enter the OAU after passing

the M40V because the attenuator of the M40V is not adjusted.

Procedure

1. Adjust the M40V on the T2000 and set the attenuation value of the corresponding channel

to 0 dB. Then, the MUT_LOS alarm is cleared.

Reference Information

In certain scenarios, the attenuation of certain channels of the M40V, D40V, VA1, and VA4

boards needs to be set manually. At the station that is configured with the M40V, D40V, VA1,

or VA4, set the attenuation value of the optical channel of the board manually to ensure the

availability of the optical channel. This is very important for the ASON feature to trigger

rerouting in the WDM network.