Description of the problem

Expand two SF64 single boards on two OSN3500s in the existing network, after connecting the pigtails at the site and searching for fiber cables on U2000, it is found that the fiber cables cannot be searched.

Processing

1. Check the network elements and the new expansion of the single board without abnormal alarms, and expansion of the single board and the host version of the matching.

2. Check the SF64 optical power is normal, the scene check the fiber connection does not exist, such as mandarin duck fiber.

3. Check the SF64 single board SDH interface configuration, found that the overhead transmission mode is GCC mode, as shown in the following figure.

The fiber optic automatic search using J0 bytes, the board is in GCC mode, does not deal with J0 bytes, so the fiber optic automatic search is not successful.

4. GCC mode can be changed to DCC mode after normal search.

Root cause

SF64 single board overhead transmission mode is GCC resulting in unsuccessful fiber cable search.

Solution

Modify the GCC mode to DCC mode and then search the cable normally.

Suggestion and Summary

SF64 and SF16 single boards support two overhead transmission modes, GCC and DCC, when the overhead is gcc mode, only the overhead of D1-D3 bytes are processed, and when the overhead is dcc mode, only the overhead bytes other than D1-D3 will be processed, so it is necessary to pay attention to the mode setting in the process of expanding the opening.