Showing posts with label ONT line board. Show all posts
Showing posts with label ONT line board. Show all posts

Friday, March 19, 2021

How do you Make Hardware and Software Loopback for OSN1800?

 How do you Make Hardware and Software Loopback for OSN1800?

The Loopback means of troubleshooting for Equipment and used to determine whether the boards, Optical interface, Electrical interface, Cables, Connectors and Cross-Connection are faulty

A.      OTU Board Loopback

B.      OTN Tributary Board Loopback

C.      OTN Line Board Loopback

D.     SDH Board Loopback

E.      PDH Board Loopback

F.       Ethernet Board Loopback

Hardware Loopback: Means an optical port connect the transmit end and receive end of the Port using a fiber and it must be performed onsite

Software Loopback: Means configure the Loop on the NMS

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A-   OTU Board Loopback: A loopback is used to determine whether the board is faulty. Types of loopback which we can apply them on The OTU boards to verify the board SDH services as the following

1-  Client –Side Out-loop  : this loop is used to detect whether the Fiber line and Connectors on the line are normal as the Following


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2-  Client –Side In-loop  : The loop is used to detect whether the received Signals are properly processed inside the board as the following 

 

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3-   WDM –Side In-loop  : this loop is used to detect whether the received Signals are properly processed inside the board as the following 

 

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4-  WDM –Side out-loop  : The loop is used to detect whether the Fiber line and Connectors on the line are normal as the following 

 

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B- OTN Tributary Board Loopback: An OTN tributary board we can do Inloop and Outloop to determine which Fault. The types of Loops as the following:

1-  Out-loop on the OTN Tributary Board  : this loop is used to Check whether optical Fibers and Connectors Functions properly  as the following 

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2-    In-loop on the OTN Tributary Board  : this loop is used to Check whether the board Properly processes received Signals as follows

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 C-OTN Line Board Loopback: An OTN line board which include In-Loop and Out-loop

1-  Out- loop on an OTN Line Board  : this loop is used to Check Fibers line and Connectors Function are Working Properly as follows

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2-  In-loop on an OTN Line Board  : this loop is used to check whether the board properly processes received Signals

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D-SDH Board Loopback:  We have out-loops and In-Loops on Optical interface on SDH boards as the Following:

1-   Out-loop on the SDH optical interface board: this loop is used to check whether the SDH interface and the external cable of the SDH board are normal and the loop does not change the signal structure within the optical interface board by the signal that is transmitted from the optical receiver module is directly looped from the SDH interface to the optical transmitter module.


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2-   VC-4 out-loop on the SDH optical interface board: The loop checks whether the VC-4 channels at the SDH interfaces and on the fibers connected to the SDH board are normal and does not change the signal structure within the optical interface board where the VC-4 signal that is transmitted from the optical receiver module is directly looped from the VC-4 channel to the optical transmitter module

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3-  VC-3/VC-12 Out-loop on the SDH optical interface board: the loop checks The VC-3/VC-12 outloop does not change the signal structure within the optical interface board where the VC-3/VC-12 signal that is transmitted from the optical receiver module is directly looped from the VC-3/VC-12 channel to the optical transmitter module.


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4- In-loop on the SDH optical interface board: The loop is used to check whether the SDH service processing module and the cross-connect board are normal a via The optical interface in-loop processes the signal at the local end within the optical interface board, where the signal that is transmitted from the cross-connect unit is looped from the SDH interface to the cross-connect unit


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5-      VC-4 in-loop on the SDH optical interface board: The loop checks whether the SDH service processing module and the cross-connect board are normal a via The VC-4 In-loop processes the signal at the local end within the optical interface board Where the VC-4 signal that is transmitted from the cross-connect unit is looped from the VC-4 channel to the cross-connect unit


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E-PDH Board Loopback: We can through PDH board apply in-loop and out-loop to test electric interface Board as the following

1-  Out-loop on the PDH Electrical interface board: The loop checks whether the PDH interface and the external cable of the PDH board are normal and does not change the signal structure within the PDH electrical interface board where the signal that is transmitted from the receive port is directly looped back to the corresponding transmit port before being processed.


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 2-   In-loop on the PDH Electrical interface board: The loop checks whether the PDH service processing module and the cross-connect board are normal by processing the signal at the local end within the PDH electrical interface board Where the signal that is transmitted from the cross-connect unit is looped back to the cross-connect unit


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F-Ethernet Board Loopback: Through ETH Board we are Classified In-loop on ETH port into

1-      In-loop PHY Port Layer Loopback: the loop checks whether the MAC layer, SDH layer, and signals of the Ethernet board are normal where the Ethernet service that is transmitted from the NE is looped from the physical layer of the Ethernet port to the SDH layer


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2-      In-loop MAC Port Layer Loopback: this loop checks whether the SDH layer and signals of the Ethernet board are normal where the Ethernet service that is transmitted from the NE is looped from the MAC layer of the Ethernet port to the SDH layer


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Finally, I hope that my technical post helps everyone to know how to make Loopback on mentioned Boards to test Optical interface, Electric interface, Connectors, Cables, Modules and Cross-Connection.

Wednesday, March 4, 2020

How to deal with Abnormal Switching of SNCP service on ONT line board NS4 of Huawei OSN8800?

This is a case about handling abnormal switching of SNCP service on ONT line board NS4 of Huawei OSN8800.

Problem Description
100G line board TN54NS4 of a customer is configured with SNCP services. It is reported that multiple abnormal switching occurs on the live network, no fiber cut occurs on the optical cable, and the optical power is normal. Therefore, the root cause analysis needs to be performed.
The networking is as follows:
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Alarm information:
ODU_SNCP_PS
Handling Procedure
1. Query the NMS alarms. It is found that the ODU_SNCP_PS alarm occurs multiple times and the SNCP switching occurs.
2. Check the current and historical alarms of the device. It is found that no fiber cut alarm is generated.
3. Continue to check the receive optical power of TN54NS4. It is found that the receive optical power is stable. Therefore, the switching is not caused by the bit errors caused by the power jitter.
4. According to the networking analysis (as shown in the following figure), it is found that SNCP switching occurs at a certain time, and services are switched from SNCP-to SNCP-protection. The switching cause may be caused by bit errors on the line. Because there is only one span between A-B, it can be confirmed that the problem is caused by this span.
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5. The customer performed an OTDR test on the optical cable between the site A and the site B. It was found that the problem was caused by the reflection point of the optical cable.

6. The reflection point has a hop contact. After the connector is cleaned, the OTDR test shows that the reflection is normal and the SNCP switching is normal.
Root Cause
The fiber jumper connector is faulty. As a result, bit errors occur due to reflection and SNCP switching is triggered.
Suggestions and Summary
1. Alarm, performance, and optical power are the basic methods for locating WDM problems.


2. Common factors related to bit errors on the line side: a, non-linear effect; b, there is an abnormal reflection point on the line side

If you encounter same issue about NS4, you can refer to this article, it would be helpful.