Remotely checking the correctness of the DCM installation.
Symptom
In the hardware installation of the OptiX BWS 1600G, because of the mis-operation of engineers, the DCM at some sites may be installed incorrectly. For example, the two directions of a DCM in an OLA site are: from east to west, C1 (20 km) and from west to east, C3 (60 km). If the two directions are installed incorrectly, the service cannot be provisioned smoothly. Hence, we need to check whether the two directions are installed in the reverse manner.
Cause Analysis
It is time-consuming to check the correctness of the DCM installation on site. We can remotely check the OAU optical power to determine whether DCM is installed correctly. The OAU provides the detection and report of optical power at five points on the board. Optical interface 3, corresponding to optical interface RDC, detects the input optical power in the middle of the board; Optical interface 5, corresponding to optical interface TDC, detects the output optical power in the middle of the board.
Because DCM is installed between TDC and RDC of the OAU, the difference in optical power between interface 5 and interface 3 is the DCM insertion loss. Because the DCM insertion loss is basically fixed, one knows what DCM model is installed according to the insertion loss.
Procedure
- Query the east-to-west OAU optical power and the difference in optical power between interface 5 and interface 3 is calculated to be 1.6 dB.
- Query the west-to-east OAU optical power and the difference in optical power between interface 5 and interface 3 is calculated to be 5.3 dB.
- This shows that the east-to-west is DCM (C1) and the west-to-east is DCM (C3). The two DCMs are installed correctly. There is no need to conduct on-site operations.
Reference Information
- The engineers must be trained before performing hardware installation. The engineers are required to install the hardware according to the cabinet fiber wiring diagram in the engineering design. Observe the label on the fiber jumper that is threaded to the DCM frame from the subrack. Note that the DCM model is indicated on the label.
- If a problem occurs during the hardware installation, do not rush to the site. Consider whether the equipment can be remotely checked.
- If the problem can be remotely resolved, use the remote method. If remote troubleshooting is impossible, the engineer has to go to the site to resolve the problem.
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