Hello everyone!
I will share with you about the IPA fiber cut detection.
Fiber Cut Detection
The system detects a fiber cut by detecting the input optical power on the OA board at the receive end. After determining a fiber cut, the IPA function is triggered. In a system where CRPC boards are used, the optical power of the backward scattering signals is very high. In this case, the input optical power of the noise can be detected on the OA board at the receive end even when the fiber is broken. Therefore, it is inaccurate to determine whether a fiber cut occurs by detecting only the LOS alarm in a system configured with CRPC boards, especially a system with a small number of wavelengths.
For the IPA function provided in earlier versions of Huawei DWDM equipment, the system determines a fiber cut by adjusting the threshold for detecting the LOS alarm on the OA board. The application range of this method, however, is limited. To improve the accuracy of determining a fiber cut, the system also detects the following conditions:
MUT_LOS alarm on the OA board
R_LOS, R_LOF, and R_LOC alarms on the OTU board
R_LOS, R_LOF, and OSC_RDI alarms on the OSC board
LOS alarm on a CRPC board
The preceding conditions can be randomly combined. When all conditions are met, the system starts the IPA function to shut down the laser on the control implementation board. When any alarm in any condition is cleared, the system restarts the laser on the control implementation board.
Boards Involved in the IPA Function
The following table lists the boards involved in the IPA function.
Function Type | Available Board Type | Function Description | Configuration Principle and Restriction |
OA detection board | OAU and OBU | Detects the LOS alarm on the board. | It is recommended to configure the OA detection board in an IPA pair. |
Control implementation board | OAU, OBU, and HBA | Shuts down the laser on the board. | The control implementation board must be set. The OA detection board and the control implementation board cannot be set using the same board. In addition, the OA detection board and the control implementation board used by an IPA pair cannot be used by another IPA pair. |
Raman Amplifier | TN11CRPC01 | l Shuts down the laser on the board after the system determines that a fiber cut occurs. l Helps determine a fiber cut. The TN11CRPC board can detect a LOS alarm. After setting a CRPC board as a Raman Amplifier board, you need to set Raman Board Threshold (dBm) and set Enable Raman Board Alarm to Enabled. | The Raman Amplifier board must be set in a system where a CRPC is used at the receive end. The Raman Amplifier board must be set to a CRPC board on the local NE. If you set a CRPC board on a remote NE as the Raman Amplifier board, the IPA function may not be restored when the communication is abnormal. |
Auxiliary detection board | OTU and OSC (SC1, SC2, and HSC1) boards | Detects the optical power of service signals to improve the accuracy of determining a fiber cut. Both OTU and OSC boards can be set as auxiliary detection boards. When multiple alarms are detected on multiple boards, these alarms are processed according to their logical relationship and then considered as a condition for determining a fiber cut. | Auxiliary detection boards are set to improve the accuracy of determining a fiber cut. A maximum of four auxiliary detection boards (including the OTU and OSC auxiliary detection boards) can be set for an IPA pair. |
Auxiliary Raman Board | TN11CRPC02 and TN11ROP | Shuts down the laser on the board after a fiber cut is detected and restarts the laser on the board after the fiber is restored. | N/A |
That's all. Here's where you may contact us:
https://forum.huawei.com/enterprise/en/Transport-Access-Network/forum/875.
Thank you!
