Hi guys!!
I would like to share with you an issue about IN_PWR_ABN -> B2_EXC -> MS_REI alarms on SL16A board.
Description:
1) Customer reports the link distance is 60Km with G.652 fiber. Therefore, the design loss is calculated as follows:
2) The link with L-16.2 SFPs (1550nm-80Km) is established, but IN_PWR_ABN alarms begin to be declared on the optical interfaces of the SL16A boards. The received optical power is outside the threshold on both sites:
3) The link is checked with an OTDR meter and it's verified that the real distance span is 39Km. Therefore, the real loss is:
Solution:
There are 2 possible solutions:
1) Install 3dB fixed attenuators at the reception of the optical interfaces at both sites.
2) Replace L-16.2 SFPs (1550nm-80Km) for L-16.1 SFPs (1310nm-40Km) on the SL16A board at both sites.
Customer chooses the solution 1 (cheaper and faster).
After installing the 3dB fixed attenuators, IN_PWR_ABN alarms disappear.
A few days later customer notifies of the appearance of B2_EXC alarm in SITE 1 and MS_REI alarm in SITE 2 (on both SL16A boards).
NOTE: After B2_EXC alarm occurs (SITE 1), the system automatically returns the MS_REI alarm to the opposite NE (SITE 2) by using the M1 byte, and the opposite NE reports the MS_REI alarm.
After reviewing the issue, result is:
Cause: The line performance deteriorates (SDH optical interface board). The optical fiber in SITE 2 is not aligned with fixed attenuator and consequently with the board's optical interface because the closed cabinet door presses the fiber (it wasn't Huawei cabinet).
Finally, customer decides to replace L-16.2 SFPs (1550nm-80Km) for L-16.1 SFPs (1310nm-40Km) on the SL16A board at both sites (solution 2 - the best technical solution).
After that, the optical power at both sites is as follows:
and B2_EXC -> MS_REI alarms disappear.
BR
