During the tests, we tried to test the protection switch and the performance of one link,We use OptiX OSN 6800 V100R004, after connecting the SDH analyzer, I found that there is a errors and some times R_LOF, in both, working and protection ways.
1) check the type of protection in the two sites.
2) Delete the protection of the first STM16 in the two sites.
3) configure the same type of protection in the two sites ( SNC/N with PM overheads)
4) test the protection switching of this link is OK.
5) test the performance of this link is OK
6) Delete and configure the same protection type of the others STM16.
7) The protection switching and performance are OK
I checked the fiber connection and the the configuration of the link( link with 4* STM16), I found that all are OK, but when I checked the configuration of the protection, I found in one site use ODUk SNCP SNC/N(with the PM overhead) and in the other site SNC/I with SM overhead.