​How to identify that the SDH line link from one NE to another NE is correct?

Hi,
If the connection is complete and optical power is ok un both link sides , then You can set the J0 byte in both sided (line board in both NE).
The default J0 is (Huwaei SBS) you can change it as you want for example the NE ID , Board Number.

Then you can check the received j0 in both sides to make sure that the connection is right.

To identify which SDH line link of an NE is correct we can do it through the J0 byte of the regeneration section of the SDH frame. In the line board of the NE of the opposite end, specifically in the header field of the regeneration section in Byte J0 you establish a known value, then in this same section but in the desired NE you check that the value of J0 is being received before mentioned if it matches, repeats the reverse operation and if the value at the opposite end matches then the end-to-end connection at the line board level is correct.

Dear lucian2003!
In addition to the methods recommended above, I remember that you can also insert an alarm to the port on the local line board to query the slot and port of the peer line board.
If you feel that the operation is complex, you can use the fiber search function of the U2000 to automatically create logical fibers.

Thank you!